Two Article Summaries

Article

Effects of Multidimensional Family Therapy (MDFT) on Nonopioid Drug Abuse: A Systematic Review and Meta-Analysis

Trine Filges1, Ditte Andersen1, and Anne-Marie Klint Jørgensen1

Abstract Purpose: This review evaluates the evidence of the effects of multidimensional family therapy (MDFT) on drug use reduction in young people for the treatment of nonopioid drug use. Method: We followed Campbell Collaboration guidelines to conduct a systematic review of randomized and nonrandomized trials. Meta-analytic methods were used to quantitatively synthesize study results. Results: The search yielded five studies that met inclusion criteria. MDFT was found to be more effective than other treatments on drug abuse problem severity and drug use frequency in the short run but not in the long run and demonstrated positive effects on treatment retention compared to control conditions. Discussion: While additional research is needed, the review offers support for MDFT as a treatment to young nonopioid drug abusers. The number of studies included in this review was limited, however, and this should be considered when interpreting the results.

Keywords abuse, systematic review, quantitative, meta-analysis

Youth drug abuse, the consumption of drugs beyond experi-

mentation and into addiction of the kind that persists beyond

the experimentation phase, is a severe problem worldwide

(United Nations Office on Drugs and Crime, 2010). Abuse of

drugs such as cannabis, amphetamine, and cocaine, referred

to in this review as nonopioids, are strongly associated with a

broad range of negative health implications such as traffic acci-

dents; sexually transmitted diseases; mental problems and sui-

cide; as well as social problems including poor academic

achievement, delinquency, and violent behavior (Deas &

Thomas, 2001; Essau, 2006; Lynskey & Hall, 2000; Nordstrom

& Levin, 2007; Office of National Drug Control Policy, 2000;

Rowe & Liddle, 2006; Shelton, Taylor, Bonner, & van den

Bree, 2009).

While cannabis, amphetamine, cocaine, and other nonopioid

drugs remain illegal in most countries, surveys indicate wide-

spread prevalence. In the United States, 25.5% of 12th-grade students report having used an illicit drug within the last month

(Johnston, O’Malley, Miech, Bachman, & Schulenberg, 2014).

In Canada, 21% of 15- to 24-year-olds report having used of some kind of illicit drug within the last year (Health Canada,

2011). In Australia, 7% of 12- to 17-year-olds report using some kind of drug within the last month (White & Smith,

2009). The European Monitoring Centre for Drugs and Drug

Addiction (EMCDDA, 2010) has found that prevalence within

Europe differs significantly from country to country but that

overall around a quarter of Europeans report having used some

kind of illicit drug in their lifetime.

The prevalence of specific kinds of illicit drug abuse varies

significantly, with cannabis generally being the most com-

monly used drug. In the United States, 22.7% of 12th-grade stu- dents report having used marijuana/hashish (types of cannabis),

4.1% used amphetamine, and 1.1% used cocaine during the last 30 days before the National Survey on Drug Use was conducted

in 2013 (Johnston et al., 2014). The European Drug Report of

2013 indicates that 11.7% of the 15- to 34-year-olds in Europe has used cannabis, 1.3% used amphetamine, and 1.9% used cocaine during the last year (EMCDDA, 2010).

Although not all drug users’ progress to severe drug abuse

and dependence, some do and therefore warrant treatment.

Individuals who warrant drug treatment are described variously

as abusers, misusers, or dependent. These specific categoriza-

tions are used in the Diagnostic and Statistical Manual of Men-

tal Disorders (DSM; American Psychiatric Association [APA],

1994, 2000, 2013). While the DSM is widely used, the Interna-

tional Statistical Classification of Diseases and Related Health

problems (ICD, now ICD-10) developed by the World Health

Organization (WHO) is also in wide use. Differences between

these rubrics concern both terminology and categorization

1 SFI Campbell, Copenhagen, Denmark

Corresponding Author:

Trine Filges, Herluf Trolles Gade 11, DK-1052 Copenhagen, Denmark.

Email: [email protected]

Research on Social Work Practice 2018, Vol. 28(1) 68-83 ª The Author(s) 2015 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/1049731515608241 journals.sagepub.com/home/rsw

criteria. For example, DSM-V (APA, 2013) includes the cate-

gory ‘‘abuse,’’ while ICD-10 explicitly avoids this term on the

grounds of its ambiguity; harmful use and hazardous use are the

equivalent terms in WHO usage, but the categories are not

identical; and while ICD-10 uses only physical and mental cri-

teria, the DSM also includes social criteria (Nordegren, 2002;

WHO, 2011).

Research draws attention to the significant gap between the

number of young people classified as in need of treatment and

the number of young people who actually receive such treat-

ment (National Survey on Drug Use and Health, 2007; Sub-

stance Abuse and Mental Health Services Administration

[SAMHSA], 2010). In the United States, for example, 7.2 mil-

lion young people are classified as needing treatment for illicit

drug abuse, but only 1.4 million of these actually receive treat-

ment at a specialty facility for an illicit drug abuse problem

(SAMHSA, 2011). When young people do receive treatment,

it is most often delivered in outpatient settings. Approximately

90% of the 89,521 clients under age 18 registered in substance abuse treatment in 2012 by SAMHSA were in outpatient treat-

ment (SAMHSA, 2013). Equal proportions of the clients under

age 18 were enrolled in facilities with a primary focus on sub-

stance abuse treatment and in facilities with a mix of mental

health and substance abuse treatment services (SAMHSA,

2013). Cognitive–behavioral therapy (CBT) and motivational

interviewing are specific therapeutic approaches that are used

to some extent by most (91% and 87%, respectively) treatment facilities (SAMHSA, 2013).

There is growing public concern about the effectiveness and

high cost of available treatments for young people and the high

rates of treatment dropout and posttreatment relapse to drug

abuse (Austin, Macgowan, & Wagner, 2005; Najavits & Weiss,

1994; Stanton & Shadish, 1997). While relapse must be

acknowledged as an expected part of any treatment process tar-

geting individual drug abuse, efforts should be made to make

treatment as attractive, accessible, and relevant as possible for

young people in order to minimize the risk of unwarranted

dropout and continuous relapse (National Institute on Drug

Abuse [NIDA], 2009; Simmons et al., 2008). Furthermore, the

services provided should be empirically supported to increase

the likelihood that (a) treatment will be successful and (b) pub-

lic spending supports the interventions that are most effective.

Young people who abuse drugs persistently and to an extent

that warrants treatment have unique needs due to their particu-

lar cognitive and psychosocial developmental stage. Recogniz-

ing that young people are particularly sensitive to social

influences, families and peer groups being highly influential,

authorities such as the U.S. NIDA recommend that youth drug

treatments facilitate positive parental and peer involvement

(NIDA, 2009, s. 22). Moreover, they recommend that other sys-

tems in which the youth participates (such as schools and ath-

letics) are also integrated into a comprehensive treatment

approach to meet the unique needs of young drug abusers

(NIDA, 2009, s. 23).

A number of studies and reviews have demonstrated posi-

tive results for family therapies. Family therapy covers a range

of different interventions and is based on different manuals and

varying theoretical sources such as behavioral and cognitive–

behavioral theory, structural and strategic family theory, and

family systems theory (Austin et al., 2005; Williams, Chang,

& Addiction Centre Adolescent Research Group, 2000).

Family-based interventions for the treatment of young drug

abusers include multidimensional family therapy (MDFT),

brief strategic family therapy, functional family therapy (FFT),

and family behavior therapy (Alexander & Sexton, 2002; Aus-

tin et al., 2005; Rowe & Liddle, 2006; Waldron & Turner,

2008; Waldron, Turner, & Ozechowski, 2006; Williams

et al., 2000). Some reviews suggest that these family-based

therapies are superior to individual-based programs in reducing

youth drug abuse (Lipsey, Tanner-Smith, & Wilson, 2010;

Waldron, 1997; Williams et al., 2000). While there is general

support for family therapy in the treatment of substance use

with young people, there is a need to synthesize individual

study results for specific family therapies to determine whether

and to what extent family therapy interventions work for young

drug abusers (Austin et al., 2005; Deas & Thomas, 2001; Wal-

dron & Turner, 2008; Williams et al., 2000).

MDFT

MDFT, developed in 1985, is a manual-based, family-oriented

treatment designed to eliminate drug abuse and associated

problems in young people’s lives (Liddle, 1999, 2002; Liddle,

Rowe, Dakof, Henderson, & Greenbaum, 2009). MDFT is one

of several family therapy forms that meet the general character-

istics of manual-based family therapies. MDFT treats young

people and their families as a system throughout treatment and

thereby recognizes the important role of the family in the

development and treatment of young people’s drug abuse prob-

lems (Liddle et al., 2001; Muck et al., 2001). MDFT’s theory of

change hypothesizes that changing the family system construc-

tively will produce changes in youths’ drug abuse (reduction or

elimination) as well as improvements in relation to other emo-

tional and behavioral problems (A. Hogue, Liddle, Dauber, &

Samoulis, 2004; Liddle, Rodriguez, Dakof, Kanzki, & Marvel,

2005). MDFT combines elements of several theoretical frame-

works, including family systems theory and developmental

psychology (Bronfenbrenner, 1979; Minuchin, 1985; Stroufe

& Rutter, 1984), ecosystems theory, and the risk and protective

model of adolescent substance abuse (Austin et al., 2005; A.

Hogue & Liddle, 1999; Liddle & Hogue, 2000). The influence

of ecological and developmental theory in MDFT is evident, as

the intervention takes into account the changing environments

and multidimensional systems in which young drug abusers

reside (Liddle, 2002; Liddle et al., 2001).

Treatment focuses on individual characteristics of the young

person, their parents, and other key individuals in the young

person’s life as well as on the relational patterns contributing

to the drug abuse and other problem behaviors. A variety of

therapeutic techniques are used to accomplish this and to

improve the young person and the family’s behaviors, attitudes,

and functioning across the variety of domains (Liddle, 1999).

Filges et al. 69

MDFT aims to reorient the young person and family toward a

more functional developmental trajectory on the basis of a vari-

ety of key principles, including (1) individual biological,

social, cognitive, personality, interpersonal, familial, develop-

mental, and social ecological aspects can all contribute to the

development, continuation, worsening, and chronicity of drug

problems; (2) the relationships with parent(s), siblings, and

other family members are fundamental domains of assessment

and change; (3) change is multifaceted and multidetermined

and relates to the youths’ cognitive and psychosocial develop-

mental stages; (4) motivation is not assumed but is malleable

and motivating the young person and family members about

treatment participation and change is a fundamental therapeutic

task; (5) multiple therapeutic alliances are required to create a

foundation for change; and (6) therapist responsibility and atti-

tude is fundamental to success (Liddle, 2010).

To produce change, MDFT proposes that therapists focus on

parenting skills and family interaction. However, MDFT stres-

ses that this is not necessarily sufficient for a change in the

young person’s drug abuse. A key idea is that therapists, in

addition to working with both internal family factors (such as

family patterns and rituals and perceptions of each other and

oneself), also need to address external systemic factors (such

as peer relations, school, and other prosocial institutions).

Thus, MDFT aims at reducing symptoms and enhancing proso-

cial and normative developmental functions in problem youths,

by targeting the family as the foundation for intervention

and simultaneously facilitating curative processes in several

domains (systems) of the young persons’ lives. Particular beha-

viors, emotions, and thinking patterns related to problem for-

mation and continuation are replaced by new behaviors,

emotions, and thinking patterns associated with appropriate

intrapersonal and familial development (Liddle, 2002; Liddle,

Cecero, Hogue, Dauber, & Stambaugh, 2006).

The comprehensive multidimensional assessment is

hypothesized as a key feature in the success of MDFT for

young people experiencing multiple problems. Assessment in

MDFT provides a therapeutic map, directing therapists where

to intervene in the multiple domains of the young person’s life.

The process involves not only the identification of different

problem areas, symptoms, and co-occurring disorders but also

risk and protective factors in all relevant domains so that these

factors can be targeted for change. Through a series of individ-

ual and family interviews, meetings with school, court, and

other mental health professionals, and observations of family

interactions, the therapist seeks to answer critical questions

about functioning in each area. First, assessment is an ongoing

process throughout therapy, continually integrated with inter-

ventions to calibrate treatment planning and solving. Second,

guided by this multidimensional assessment, the model

addresses common root factors underlying a range of emotional

and behavioral symptoms that co-occur with young persons’

drug abuse.

MDFT is organized into three phases, based upon knowl-

edge of what is considered to be normal cognitive and emo-

tional development for young people. Each phase represents

one of several targets for assessment, intervention, and change,

and the therapist will not progress to the next phase until the

therapy has completed the current phase. The three phases

structuring the MDFT intervention aim to (1) form therapeutic

alliances and build the foundation for therapy, (2) take action

and make changes, and (3) seal the changes and guide the fam-

ily members toward creating a healthy internal relationship.

Each phase is implemented through four types of treatment ses-

sions (Liddle, 2002; Liddle, Dakof, Turner, Henderson, &

Greenbaum, 2008; Liddle et al., 2006): individual sessions with

the young person, sessions with the parent(s), sessions with

other family members, and systems external to the family.

Sometimes, the assessment of Component 3 is split into two,

(a) a component concerning other family members and (b) a

component concerning systems external to the family, and

thereby five components are presented in some MDFT studies

(Liddle, 2002) and sessions to change the parent(s)–young per-

sons interaction(s).

The emphasis on therapists working simultaneously with

several systems to produce change in young people’s problem

behavior is not unique to MDFT. Rather, this is generally

emphasized in family therapy approaches (Dakof, Godley, &

Smith, 2011). Likewise, these approaches in general also

instruct therapists to be highly nonpunitive and nonjudgmental

toward youth and parents and stress that therapists should col-

laborate with youth and parents to develop meaningful, client-

driven goals (Dakof et al., 2011). The distinctiveness in MDFT

derives from the assembly of theories, methods, and techniques

into specific therapeutic principles that guide the intervention

step-by-step as outlined in the following section.

Previous reviews ( Vaughn & Howard, 2004; Waldron &

Turner, 2008) indicate that MDFT is a promising treatment for

young drug abusers. However, the only meta-analysis thus far

conducted (Waldron & Turner, 2008) included MDFT as part

of a broad category of family therapy rather than including

MDFT as a distinct treatment model. In contrast, this review

examines the effect of MDFT and by aggregating results of all

relevant studies on MDFT and so contributes to the knowledge

about treatment of young drug abusers and their families. The

review informs practice by exploring whether results indicate

that MDFT works better for some client groups than others

based on characteristics such as age, gender, minority background,

family composition (e.g., single parents), and co-occurring con-

ditions. As previous reviews (e.g., Waldron & Turner, 2008)

indicate that individual treatment outcomes vary widely within

intervention models, it is important to investigate who might

benefit the most from MDFT. The hypothesis is that MDFT is

not similarly efficacious for all client groups, and the review

investigates whether it is possible to identify subgroups that

benefit more than others.

Purpose of the Present Study

Drug treatment targeting young drug abusers is challenging and

costly, as interventions are often plagued by high dropout rates

and posttreatment relapse into drug abuse. Given the growing

70 Research on Social Work Practice 28(1)

interest among policy makers in increasing funding for

evidence-based interventions, there is a need to add to the evi-

dence base with a systematic review on promising treatment for

young drug abusers. The specific aim of this review was to

evaluate current evidence about the effects of MDFT on drug

abuse reduction for young people (aged 11–21 years) in treat-

ment for nonopioid drug abuse. Further objectives of this

review were to examine the moderators of drug abuse reduction

effects and to examine whether MDFT works better for partic-

ular groups.

Method

Systematic review methods, following the Campbell Colla-

boration (2014) guidelines, were used to conduct this study,

and the meta-analytic methods were used to synthesize study

results. The protocol for this review is registered and published

in the Campbell Collaboration library (Rasmussen, Lindstrom,

Kowalski, Filges, & Jorgensen, 2012).

Criteria for Considering Studies for This Review

Types of studies. The study designs eligible for inclusion in the review included randomized controlled trials (RCTs), quasi-

RCTs, and non-RCTs (NRCTs; in which all parts of the study

are prospective, i.e., recruitment of participants, assessment of

baseline, allocation to intervention, selection of outcomes, and

generation of hypotheses).

Types of participants. The population included in this review was young people aged 11–21 years referred to or in treatment for

using nonopioid drugs (e.g., cannabis, amphetamine, ecstasy,

or cocaine). Definitions of young people, and the age at which

a person is considered a young person and may be entitled to

special services such as drug treatment, vary internationally

(United Nations, n.d.). Age-group distinctions for young peo-

ple are unclear, as the boundaries are fluid and culturally spe-

cific (Weller, 2006). Furthermore, young people start

experimenting with illegal drugs at different ages in different

countries (Hibell et al., 2009), and the pattern of movement

from dependence on parents to independent living vary inter-

nationally. In order to capture international differences, we

have set the age range from 11 to 21 years (Danish Youth

Council, 2011; Hibell et al., 2009; SAMHSA, 2010; United

Nations, n.d.).

Because no universal consensus exists on categories which

should be used when classifying drug abusers, and different

assessment tools and ways of classifying the severity of drug

abuse are applied in different research studies (APA, 2000;

Nordegren, 2002; WHO, 2011), we included all participants

referred to or in treatment for nonopioid drugs regardless of any

formal drug abuse diagnosis. The main criterion for inclusion

was that the young person was enrolled to participate in the

treatment (i.e., the intervention or a comparison condition).

Referral to and enrollment in drug abuse treatment suggests a

level of drug abuse such that a significant other or authority

(or the young person themselves) has found it necessary to seek

treatment.

We did not include any studies where the young drug abuser

had been placed outside the family home (e.g., inpatient treat-

ment or incarceration in a locked facility), and this is because

MDFT is a family intervention requiring the active participa-

tion of the young drug abuser and his or her family with the aim

of improving family functioning, and the core condition of the

program would be seriously compromised if the young person

was not residing within the family home.

Types of interventions. The review included outpatient manual- based MDFT interventions of any duration. The MDFT inter-

ventions were required to be interventions that did not include

overnight stays in a hospital or other treatment facility.

Types of comparison conditions. Eligible control and comparison conditions included no intervention, wait-list controls, and

alternative interventions, as we were interested in both absolute

and relative effects. Due to ethical considerations and the

nature of the problem (i.e., young people’s drug abuse), we

anticipated the likelihood of finding a no treatment control

group to be small.

Types of outcomes. The primary outcome of interest to this review was abstinence or reduction in drug abuse as measured

by, for example, (1) biochemical test (e.g., urine screen mea-

sures for drug abuse), (2) self-reported estimates on drug abuse

(e.g., time line follow back interview; Sobell & Sobell, 1992),

or (3) psychometric scales (e.g., Addiction Severity Index;

McLellan, Luborsky, O’Brien, & Woody, 1980). In addition

to the primary outcome of interest, we also examined effects

on the following secondary outcomes: family functioning; edu-

cation or vocational involvement; retention (e.g., measured by

days in treatment, completion rates, and/or attrition rates); risk

behavior, such as crime rates and prostitution; and other

adverse effects (e.g., measured by rates of hospitalization, sui-

cide, and over doses). We did not exclude studies on the basis

of whether they reported any of these secondary outcomes.

Search Methods for Identification of Studies

One review author (AKJ) ran the searches. We searched 16

international and Nordic bibliographic databases, performed

an extensive search for gray literature, and hand-searched five

core journals in October 2014. Furthermore, reference lists of

relevant reviews were checked, and 10 international experts

were contacted to identify unpublished or ongoing studies. For

additional details of the search methods, see Filges, Rasmus-

sen, Andersen, and Jørgensen (2015).

Study Selection and Data Extraction

One reviewer (MS) and one member of the review team (SLO)

independently read titles and available abstracts of reports and

articles identified in the search to exclude reports that were

Filges et al. 71

clearly irrelevant. Citations considered relevant by at least one

reviewer were retrieved in full-text versions. If there was insuf-

ficient information in the title and abstract to judge relevance,

the full text was retrieved. After screening, one review author

(PSR) and one member of the review team (SLO) read the

full-text versions to ascertain eligibility based on the selection

criteria. Any disagreements about eligibility were resolved by

discussion and consultation with a third reviewer (KK). Rea-

sons for exclusion have been documented for each study

retrieved in full text (see Filges et al., 2015, for reasons for

exclusion). The study inclusion screening sheet was piloted and

adjusted as required by the review authors and used throughout

screening.

Data and information were extracted from each included

study on characteristics of participants (e.g., age, gender, and

drug abuse history), intervention characteristics and control

conditions, research design, sample size, outcomes, and results.

One review author (PSR) coded the included studies and a sec-

ond reviewer (KK) checked the coding. The coding sheet was

piloted on several studies. Numeric data extraction was carried

out by one review author (TF) and checked by a member of the

review team (ADK).

We also assessed the methodological quality of studies

using a risk of bias model developed by Professor Barnaby

Reeves in association with the Cochrane Nonrandomized

Studies Methods Group (Reeves, Deeks, Higgins, & Wells,

2011). This model, an unpublished extension of the existing

Cochrane Collaboration’s risk of bias tool (J. P. T. Higgins

& Green, 2008), covers both risk of bias in RCTs and in

NRCTs that have a well-defined control group. The extended

model is organized and follows the same steps as the existing

Risk of Bias model according to the Cochrane Handbook,

Chapter 8 (J. P. T. Higgins & Green, 2008). Reviewers (PSR

and KK) independently assessed the risk of bias for each

included study. Disagreements were resolved by discussion

and consultation with a third reviewer with content and statis-

tical expertise (TF).

Data Analytic Strategy

Measures of treatment effect. Standardized mean differences (SMD) were used as the effect size metric for school grades,

family functioning, drug abuse problem severity, and drug

abuse frequency. Hedges g was used for estimating SMDs, and

the data used for these calculations were means, standard

deviations, and sample size.

Odds ratios (ORs) were used as the effect size metric for

retention, and the data used for these calculations were number

of events and sample size. Computations were carried out with

the natural logarithm of the OR. Software used for statistical

analyses was RevMan 5.0.

Unit of analysis issues. No studies were found with multiple inter- ventions per individual or cluster randomized trials. For studies

with multiple time points, separate analyses were performed

for 6 and 12 months postintake. Treatment termination and 6-

month follow-up were used as equivalents in two studies

(Liddle et al., 2001, 2008). Two studies (Dennis et al., 2004a,

2004b; Liddle et al., 2001) had two comparison groups with

different individuals. The control groups were not pooled, and

we performed separate analyses including the different control

groups, where these two studies provided relevant outcome

measures. Assessment of heterogeneity in primary outcome

was made with w2 (interpreted cautiously due to low statistical power), I2, and t2 statistics (J. P. Higgins, Thompson, Deeks, & Altman, 2003). We were unable to comment on the possibility

of publication bias because there were insufficient studies for

the construction of funnel plots. Selective reporting has been

considered in the risk of bias assessment and the results are

reported in the Results section.

Data synthesis. All analyses were inverse variance weighted using random effects statistical models that incorporate both

the sampling variance and the between-study variance compo-

nents into the study-level weights. Random effects weighted

mean effect sizes were calculated using 95% confidence inter- vals (CIs). Graphical displays of effect sizes (forest plots) are

provided in the section ‘‘Effects of the Interventions’’

subsequently.

We did not find any studies comparing MDFT to no treat-

ment or to untreated wait-list controls, and so were unable to

examine the absolute effects of MDFT. Our analysis of the rela-

tive effects of MDFT was conducted on studies that compared

MDFT to other interventions and/or to treatment as usual

(TAU). All follow-up durations reported in the primary studies

were recorded. We performed separate analyses at 6 months

and at 12 months postintake.

Subgroup, moderator, and sensitivity analyses. We did not identify sufficient studies to allow any subgroup or moderator analysis

to be conducted. Sensitivity analysis was used to evaluate

whether the pooled effect sizes were robust across components

of risk of bias. We conducted a sensitivity analysis for the

incomplete outcome data and other bias components of the risk

of bias checklists by removing studies scoring 4 (see the previ-

ous section ‘‘Assessment of risk of bias in included studies’’ for

a definition).

Results

We identified 6,519 potential relevant records after excluding

duplicates (database search, 1,425; gray search, 898; hand

search, snowballing, and other resources, 4,196). All 6,519

records were screened based on title and abstract. Of these,

170 were retrieved and screened in full text. One hundred and

fifty-four records did not fulfill the screening criteria and were

excluded. One paper from the snowball search was included. A

total of five unique studies, reported in 16 papers, were

included in the review (see Figure 1 for search and selection

flowchart).

72 Research on Social Work Practice 28(1)

Description of the Studies

Five studies published in 16 articles between 2001 and 2014

met our inclusion criteria. Four of the included studies were

conducted in the United States and one was conducted in five

European countries. All included studies were described by

investigators as RCTs. Three employed a block randomized

design (Dennis et al., 2004a, 2004b; Liddle et al., 2008; Rigter

et al., 2011), one study allocated participants using an urn pro-

cedure (Liddle et al., 2009), and one study did not report the

randomization procedure (Liddle et al., 2001). Three studies

were conducted by MDFT program developers (Liddle et al.,

2001, 2008,, 2009), one study was ‘‘semi-independent’’ (con-

ducted by an independent investigator with the program devel-

oper as coauthor; Dennis et al., 2004a, 2004b), and one study

was conducted by independent investigators (Rigter et al.,

2011). See Table 1 for a summary of the included studies.

Liddle, Rowe, Dakof, Henderson, and Greenbaum (2009). The first study is a RCT on the effects of MDFT on low-income, ethni-

cally diverse young people aged 11–15 years who were drug

abusers. It was performed in The Village South, Inc., a nonpro-

fit community drug abuse treatment agency in Miami, FL.

The study was reported in three articles: Liddle, Rowe, Dakof,

Ungaro, and Henderson (2004); Henderson, Rowe, Dakof,

Hawes, and Liddle (2009); and Liddle et al. (2009). We refer to

this study as Liddle (2009), unless specific results from the other

two papers are addressed, in which case we will cite as Liddle

(2004) or Henderson, Rowe, Dakof, Hawes, and Liddle (2009).

Database Search SocIndex 202 Eric 21 SSCI 392 SCI 344 Criminal Justice Ab 23 Cinahl 21 Social Care Online 37 PsycInfo 145 Cochrane 52 Medline 60 Embase 115 Bibliotek.dk 345 Libris 39 Bibsys 21

Total 1817

Grey literature Dissertation 58 Google 350 Google Scholar 150 Governmental sites 263 Multi-disciplinary sites 9 Subject specific sites 68 Total 898

Hand search Addiction 2037 Journal of Substance

Abuse Treatment 776

Journal of Clinical Child and Adolescent Psychology

392

Journal of Consulting & Clinical Psychology

527

Research on Social Work Practice

458

Snowball 3 Expert list 4 Total 4196

392 excluded for being duplicates.

6,519 potential relevant studies (Databases: 1,425, grey: 898 and 4,196 from hand search etc.)

screened for retrieval.

6,349 articles excluded for not fulfilling first level

screening questions 170 papers (121 databases, 46 grey and 3

snowballs) retrieved for full text screening.

5 trials (16 papers) met eligibility criteria and were included in the review.

16 papers met inclusion criteria and were assessed for data extraction.

154 papers were excluded for not

fulfilling the second level screening

questions.

Figure 1. Study selection flowchart.

Filges et al. 73

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A C

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)

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r 3 , 6 , 9 , an

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s

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sc en

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T A

U ¼

tr ea

tm en

t as

u su

al .

74

Dennis et al. (2004a, 2004b). This is a RCT on the effects of MDFT on drug (primarily cannabis) with young people aged

12–18 years, conducted at two different sites in Philadelphia,

United States (The study refers to four different sites, due to

there being two trials in the study, but only one of the trials con-

cerns MDFT). The study was published as Shelef, Diamond,

Diamond, and Liddle (2005) as Dennis et al. (2004a, 2004b).

This study will be referred to as Dennis (2004).

Liddle et al. (2001). This is a RCT on the effects of MDFT on drug using 13- to 18-year-olds conducted in the United States

at an unspecified location. This study will be referred to as Lid-

dle (2001).

Liddle, Dakof, Turner, Henderson, and Greenbaum (2008). This is a RCT on the effects of MDFT with drug using 13- to 17-year-

olds who were primarily African American and from low-

income families. The study was conducted in the Northeast

United States, at unspecified locations, and was published

in four articles: Henderson, Dakof, Greenbaum, and Liddle

(2010); A. Hogue, Dauber, Samuolis, and Liddle (2006); A.

Hogue et al. (2008); Liddle et al. (2008). This study will be

referred to as Liddle (2008).

Rigter et al. (2011). This study is a RCT on the effects of MDFT with 13- to 18-year-olds with a cannabis use disorder. The

study (also termed the International Cannabis Need of

Treatment [INCANT] trial) was conducted in five European

countries: Germany, France, the Netherlands, Belgium, and

Switzerland, and the project leader and The University of

Miami Center for Treatment Research on Adolescent Drug

Abuse staff from Miami visited the nominated centers in each

country. They then selected the following centers: the depart-

ment of psychiatry of Brugmann University Hospital in Brus-

sels, Therapieladen in Berlin, Center Emergence in Paris

with suburban CEDAT (Conseils Aide et Action contre le Tox-

imanie) subsites in Mantes la Jolie and St Germain en Laye,

and the twinning sites of Parnassia Brijder (Mistral, youth

addiction care) and De Jutters (Palmhuis, youth forensic care)

in The Hague. All these sites did well in the pilot study and

joined the INCANT trial. In Switzerland, the pilot study sites

in Zurich, Basel, and Bern were replaced by Phénix (Geneva)

for the actual trial, as the potential for recruiting substance

abusing adolescents was better there. This study was published

in four articles: Rigter et al. (2013), Phan et al. (2011), Schaub

et al. (2014), and Rigter et al. (2011). This study will be

referred to as Rigter (2011).

Risk of Bias in Included Studies

The included studies varied on risk of bias judgments, and no

single study could be characterized as a robust RCT with low

risk of bias on all assessed risk of bias items. The ratings of

each study in relation to the nine domains in the Risk of Bias

tool are summarized in Table 2. Overall, all studies were RCTs,

with two studies (Liddle, 2001, 2009) having used blinding in

the allocation procedure. Two studies had very low levels of

missing data (Dennis, 2004; Liddle, 2009), and two studies had

relatively high levels (Liddle, 2001, 2008). All except one

study (Liddle, 2001) dealt with missing data. In regard to selec-

tive reporting, all studies reported data on the primary outcome

reduction in substance abuse. We were able to locate a protocol

and an a priori analysis plan for two studies (Dennis, 2004; Rig-

ter, 2011). The predictability of treatment assignment is an

issue for all constrained randomization algorithms. None of the

studies were rated 1 (low risk of bias) on this domain: Dennis

(2004), Liddle (2008), and Rigter (2011) because block rando-

mization was used; Liddle (2009) because an urn procedure

was used; and Liddle (2001) because the randomization proce-

dure was not described. Confounding was not relevant in the

review, since we did not find any NRCTs meeting the inclusion

criteria.

Effects of the Interventions on Primary Outcomes

It was possible to measure reduction in drug abuse by drug

abuse frequency reduction as well as by reduction in drug

abuse problem severity. All five studies provided data that

enabled the calculation of comparable effect sizes on drug

abuse problem severity reduction, while four studies provided

data that enabled the calculation of comparable effect sizes on

drug abuse frequency reduction. One study, Liddle (2001),

provided a drug abuse classification scheme as the only mea-

sure of drug abuse reduction. We judged that the drug abuse

classification scheme compared best with the measures of

drug abuse problem severity provided in the other studies.

Drug abuse frequency and problem severity reduction are

measured as decreases, hence a negative effect size favors

MDFT.

Table 2. Risk of Bias Assessment.

Risk of Bias Domain Rigter 2011

Liddle 2001

Liddle 2008

Dennis 2004

Liddle 2009

Sequence generation L U L L L Allocation concealment L U U L U Blinding outcome assessors

Primary outcomes 3 1 U U 1 Secondary outcomes 3 U U U 1

Incomplete outcome data Primary outcomes 3 4 4 1 1 Secondary outcomes 3 4 n/a 1 1

Free of selective reporting

Primary outcomes 1 1 1 1 1 Secondary outcomes 4 2 n/a 4 1 Retention 1 3 1 U

A priori protocol Yes U U Yes U A priori analysis plan Yes U U Yes U Free of other bias 4 U 4 3 2

Note. In the 5-point scale, 1 corresponds to low risk of bias and 5 corresponds to high risk of bias. L ¼ low risk of bias; H ¼ high risk of bias; U ¼ unclear risk of bias; n/a ¼ not applicable.

Filges et al. 75

MDFT was compared to other interventions in all the

included studies, and so we were only able to analyze the rela-

tive effects of MDFT. Two studies, Liddle (2001) and Dennis

(2004), had two comparison groups with different individuals,

and we performed separate analyses including the different

control groups, where these two studies provided relevant out-

come measures. In Dennis (2004), one comparison intervention

was CBT-informed individual therapy (multifamily educa-

tional therapy[MET]/CBT5), and the second comparison was

Adolescent Community Reinforcement Approach (ACRA).

In Liddle (2001), the two comparison interventions were MEI

and adolescent group therapy (AGT). For purposes of reporting

results with the different arms of the included studies, we

labeled the different comparison groups as follows: 1 refers

to the AGT comparison group in Liddle (2009), 2 refers the

MEI comparison group in Liddle (2001), A refers to the

MET/CBT5 comparison group in Liddle (2001), and B refers

to the ACRA comparison group in Dennis (2004). For example,

the analysis labeled 1A would have used the AGT comparison

group from Liddle (2009) and the MET/CBT5 comparison

group from Liddle (2001).

Drug abuse problem severity 6 months postintake. All five studies examined drug use problem severity at 6 months postintake.

Pooled results showed a statistically significant effect of

MDFT for drug abuse problem severity reduction. The random

effects weighted SMD for Analysis 1A was �0.35 (95% CI ¼ [�0.59, �0.11], p ¼ .004), for Analysis 1B, SMD ¼ �0.33 (95% CI ¼ [�0.59, �0.08], p ¼ .01), for Analysis 2A, SMD ¼ �0.31 (95% CI ¼ [�0.53, �0.10], p ¼ .004), and for

Analysis 2B, SMD ¼ �0.30 (95% CI ¼ [�0.53, �0.07], p ¼ .01). There was a statistically significant heterogeneity of effects between studies in Analysis 1A (t2 ¼ .04; Q ¼ 10.12, p ¼ .04), Analysis 1B (t2 ¼ .05, Q ¼ 11.67, p ¼ .02), and Analysis 2B (t2 ¼ .04; Q ¼ 9.64, p ¼ .05). In Analysis 2A, there was no statistical significant heterogeneity

(t2 ¼ .03; Q ¼ 8.18, p ¼ .09). The forest plots for Analyses 1A and 2A are displayed in Figures 2 and 3. For forest plots for

Analyses 1B and 2B, see Filges, Rasmussen, Andersen, and

Jørgensen (2015).

Drug abuse problem severity 12 months postintake. All five included studies examined drug abuse severity at 12 months

postintake. Pooled results showed a statistically significant

effect of MDFT for drug abuse problem severity reduction. The

random effects weighted SMD for Analysis 1A was �0.25 (95% CI ¼ [�0.39, �0.10], p ¼ .0007), for Analysis 1B, SMD ¼ �0.23 (95% CI ¼ [�0.39, �0.06], p ¼ .007), for Analysis 2A, SMD ¼ �0.27 (95% CI ¼ [�0.43, �0.11, p ¼ .001), and for Analysis 2B, SMD ¼ �0.25 (95% CI ¼ [�0.43, �0.07], p ¼ .007). Heterogeneity of effects among studies was not sta- tistically significant in Analysis 1A (t2 ¼ .00; Q ¼ 4.19, p ¼ .38), analysis 1B (t2 ¼ .01; Q ¼ 5.26, p ¼ .26), Analysis 2A (t2 ¼ .01; Q ¼ 4.97, p ¼ .29), and Analysis 2B (t2 ¼ .01; Q ¼ 6.17, p ¼ .19). The forest plots for Analysis 1A and 2A are displayed in Figures 4 and 5. For forest plots for Analyses

1B and 2B, see Filges et al. (2015).

Drug abuse frequency 6 months postintake. Four studies reported data on the drug abuse frequency reduction (Dennis, 2004;

Figure 2. Drug abuse problem severity at 6 months postintake 1A.

Figure 3. Drug abuse problem severity at 6 months postintake 2A.

76 Research on Social Work Practice 28(1)

Liddle, 2008, 2009; Rigter, 2011). The random effects weighted

SMD for Analysis A was �0.24 (95% CI ¼ [�0.43, �0.06], p ¼ .01) and for Analysis B, SMD ¼ �0.25 (95% CI ¼ [�0.40, �0.11], p ¼ .0007). Heterogeneity of effects among studies was not statistically significant in Analysis A

(t2 ¼ .01; Q ¼ 4.63, p ¼ .2) and Analysis B (t2 ¼ .00, Q ¼ 3.11, p ¼ .37). The forest plot for Analysis A is displayed in Figure 6. Forest plot for Analysis B can be found in Filges

et al. (2015).

Drug abuse frequency 12 months postintake. Four studies mea- sured drug abuse frequency at 12 months postintake. Pooled

results showed no statistically significant effect of MDFT for

drug abuse frequency reduction. The random effects weighted

SMD for Analysis A was �0.28 (95% CI ¼ [�0.63, 0.07], p ¼ .11) and for Analysis B, SMD ¼ �0.28 (95% CI ¼ [�0.63, 0.07], p¼ .11). There was a statistically significant heterogene- ity of effects among studies in Analysis A (t2¼ .10; Q¼ 15.43,

p ¼ .001) and Analysis B (t2 ¼ .10; Q ¼ 15.45, p ¼ .001). The forest plot for Analysis A is displayed in Figure 7. For forest

plot for Analysis B, see Filges et al. (2015).

Effects of Interventions on Secondary Outcomes

Family functioning. It was not possible to perform a meta-analysis on family functioning; however, three studies provided data to

calculate an effect size on at least one measure of family func-

tioning. One study, Liddle (2001), used a rating scale that

assessed the degree of family functioning from 1 (optimal func-

tioning) to 10 (severely dysfunctional). Family functioning was

measured as a decrease, hence a negative effect size favors

MDFT. Results showed no significant differences between

MDFT and the MEI treatment either at 6 months postintake

(SMD ¼ 0.25; 95% CI ¼ [�0.23, 0.73]) or at 12 months post- intake (SMD ¼ �0.34; 95% CI ¼ [�0.82, 0.15]). Results showed no significant differences between MDFT and the AGT

Figure 4. Drug abuse problem severity at 12 months postintake 1A.

Figure 5. Drug abuse problem severity at 12 months postintake 2A.

Figure 6. Drug abuse frequency at 6 months postintake A.

Filges et al. 77

treatment at 6 months postintake (SMD ¼ �0.30; 95% [CI ¼ �0.80, 0.21]), but a significant difference which favored MDFT at 12 months postintake (SMD ¼ �1.26; 95% CI ¼ [�1.81, �0.70]). Liddle (2009) measured family func- tioning in terms of positive and negative family interactions.

Results showed no significant differences between MDFT and

the peer group on positive or negative family interactions at 6

or 12 months postintake. Rigter (2011), reported in Schaub

et al. (2014), measured family functioning in terms of conflict

and cohesion. Results showed no significant differences on

conflict or cohesion between MDFT and the TAU comparison

at 6 or 12 months postintake. The full results including forest

plots can be found in Filges et al. (2015).

Education or vocational outcomes. Two studies (Liddle, 2001, 2009) provided data that enabled the calculation of an effect

size for grade point average at 6 months postintake. Pooled

results did not show a statistically significant effect of MDFT

for school grade improvement at 6 months postintake when

using the AGT comparison in the Liddle (2001; SMD ¼ 0.38; 95% CI ¼ [�0.25, 1.01]) and a marginal statistically signifi- cant effect when using the MEI comparison in Liddle (2001;

SMD ¼ 0.47; 95% CI¼ [0.01, 0.92]). There was no statistically significant heterogeneity between studies in any of the analyses

(t2 ¼ .15; Q ¼ 3.54, p ¼ .06 and t2 ¼ .05, Q ¼ 1.96, p ¼ .05). However, the magnitude of the effect sizes differ markedly, and

with only two studies, the power to detect heterogeneity is very

low. Forest plots can be found in Filges et al. (2015).

Retention. We used the information reported in all five stud- ies to examine retention. Results were measured as OR

nonevent, implying that an OR of less than one favors

MDFT. Three studies (Dennis, 2004; Liddle, 2001, 2008)

found no difference between retention rates. In the remain-

ing two studies, the difference between retention rates

between treatments favored MDFT (Liddle, 2009; Rigter,

2011) and was statistically significant. Note that the magni-

tudes of the effect sizes of these two studies and the width

of the CIs were quite distinct from the three other studies

(Dennis, 2004; Liddle, 2001, 2008). Pooled results showed

a statistically significant effect of MDFT for retention when

using the AGT comparison in Liddle (2001), but the effect

was not statistically significant when using the MEI com-

parison in Liddle (2001). The random effects weighted OR

for Analysis 1A was 0.44 (95% CI ¼ [0.21, 0.94], p ¼ .03), for Analysis 1B, OR ¼ 0.45 (95% CI ¼ [0.21, 0.95], p ¼ .04), for Analysis 2A, OR ¼ 0.48 (95% CI ¼ [0.22, 1.05], p ¼ .07), and for Analysis 2B, OR ¼ 0.49 (95% CI¼ [0.22, 1.07], p¼ .07). There was statistically signif- icant heterogeneity of effects among studies in all analyses.

See Filges et al. (2015) for the forest plots.

Risk behavior. One study, Rigter (2011), provided data on exter- nalizing disorders/symptoms (e.g., aggression and delin-

quency) measured by the Youth Self-report and the Child

Behavior Checklist, and another study, Liddle et al. (2009),

reported delinquency. Results showed no significant differ-

ences between MDFT and TAU on either of the scales. No sig-

nificant differences between MDFT and peer group were found

at 6 months postintake. Full results and forest plots can be

found in Filges et al. (2015).

Other adverse effects. No other adverse effects (such as rates of hospitalization, suicide, or over doses) were provided in any of

the five studies.

Sensitivity analysis. Sensitivity analyses were performed for the primary outcomes, drug abuse problem severity, and drug

abuse frequency. We examined the robustness of conclusions

when the studies scoring 4 on the incomplete outcome data

item (Liddle, 2001, 2008) and the other bias item (Liddle,

2008; Rigter, 2011), respectively, were removed from the anal-

yses. For drug abuse problem severity, the SMD remains statis-

tically significant and still favors MDFT for most of the

comparisons at the 12 months postintake when the studies scor-

ing 4 are removed. However, the effect becomes no longer sig-

nificant at 6 months postintake when studies scoring 4 on the

incomplete outcome data item are removed. The relative reduc-

tion remains significant and becomes larger for two of the con-

trasts (1A and 2A) at 6 months postintake when studies scoring

4 on the other bias item are removed. In both cases, the relative

reduction becomes marginally larger at 12 months postintake.

As expected, when studies are removed from the analysis, the

CIs become wider, and there is however considerable overlap

between CIs. For drug use frequency, the SMD ceases to be sta-

tistically significant for most of the comparisons when studies

scoring 4 are removed. At 6 months postintake, the results are no

longer statistically significant when the comparison used in

Figure 7. Drug abuse frequency at 12 months postintake A.

78 Research on Social Work Practice 28(1)

Dennis (2004) is MET/CBT5, whereas they are still statistically

significant when the comparison used in Dennis (2004) is

ACRA. See Filges et al. (2015) for full results of the sensitivity

analyses.

Discussion and Application to Practice

Our main objective was to evaluate the current evidence on the

effect of MDFT on drug abuse reduction for young people in

treatment for nonopioid drug abuse. Further objectives of this

review were to examine the moderators of drug abuse reduction

effects and to examine whether MDFT works better for partic-

ular groups. Unfortunately, it was not possible to assess this

second review objective because of the limited number of stud-

ies. Five RCTs of MDFT met the inclusion criteria for this

review. All five studies compared MDFT to other treatments,

mainly CBT or ‘‘CBT-informed’’ interventions, thus, it was not

possible to analyze the absolute effect of MDFT. Two studies,

Liddle (2001) and Dennis (2004), had two comparison groups

with different individuals, and the Rigter (2011) study was car-

ried out in five different countries with TAU as the comparison

condition, which varied across countries.

The present study findings indicate that MDFT was more

effective for reducing drug use problem severity and frequency

at 6 months and for reducing drug use problem severity at

12 months postintake compared to youth who received CBT,

TAU, MET/CBT5, and ACRA. The pooled effect sizes are,

however, small and CIs are often close to zero. The statistical

significance of the pooled results is sensitive to the removal of

studies with methodological weaknesses at 6 months postintake

but not at 12 months postintake. The available data thus support

the hypothesis that there is an effect on drug abuse problem

severity and frequency reduction for youth who receive MDFT

compared to other treatments. However, the effect appears to

vanish 12 months after intake for drug use frequency.

Although drug use frequency and severity were the primary

outcomes examined in this study, authors of the included stud-

ies also measured a number of other variables, including family

functioning, school grades, and retention. It was not possible to

perform a meta-analysis on family functioning, as only three

studies provided data and the measures used were not compa-

rable. However, there was a lack of evidence of positive effects

of MDFT on family functioning compared to MEI, peer group,

and TAU at time point and AGT at 6 months postintake. Two

studies reported school grades, and however, only data at

6 months postintake were provided. Meta-analysis favored

MDFT compared to peer group and AGT/MEI. However CIs

were wide and inconsistent across comparison groups used in

the analysis. In terms of the effects of MDFT on retention, the

results indicate that retention may be positively affected by

structured MDFT treatment compared to the less structured

control conditions of CBT, TAU, MET/CBT5, and ACRA.

The present review improves upon and expands prior narra-

tive and quantitative reviews. Overall, prior reviews generally

supported MDFT but were largely based on one or few

included studies and many did not quantitatively synthesize

effects across studies. Vaughn and Howard (2004) examined

several interventions for drug-using youth, and the conclusions

concerning MDFT were based solely on Liddle (2001) with the

authors concluded that MDFT met evidence of clinically mean-

ingful effect. Waldron and Turner (2008) and Bender, Tripodi,

Sarteschi, and Vaughn (2011) used meta-analysis to evaluate

various interventions, including family therapy, individual

therapy, CBT (individual and group), and ‘‘minimal treatment

control conditions,’’ for drug-using youth. Both reviews con-

cluded that MDFT, along with other interventions evaluated

(e.g., FFT and group CBT), was effective in the treatment of

drug-using youth.

Although there is some evidence that MDFT may be effec-

tive in the treatment of substance use with youth on certain out-

comes, we agree with prior reviews that more research is

needed, particularly with regard to moderators and identifica-

tion of particular subgroups of youth who may be more likely

to respond to specific interventions. We had planned to assess

moderators in the present review. However, the lack of empiri-

cal evidence obscured the possibility of assessing moderators

of effect and effects on subgroups.

Although this review improves upon and expands upon prior

reviews, consideration should be given to the limited number of

studies providing data that enable a calculation of an effect size

regarding drug abuse reduction. The conclusions that can be

drawn from using MDFT to treat young drug abusers compared

to other treatments would be more convincing if more studies

were available. The pooled effect sizes are small and CIs are

often close to zero. Moreover, while all five included studies

were RCTs, none can be characterized as a robust RCT with

low risk of bias on all assessed risk of bias items. Four of the

five studies originated from North America, which may limit

the applicability of the evidence to a specific social and cultural

setting and may limit generalizability of the present study’s

findings. Three of the included studies were conducted by

MDFT program developers, and one study was conducted by

an independent investigator with a program developer as a

coauthor; thus, these studies may be biased in favor of MDFT

and thus upwardly bias the mean effects. This indicates a need

for more well-conducted studies of MDFT interventions in

countries other than United States and by independent investi-

gators. Concerning limitations in the review process, the nar-

row search strategy performed in this review may limit the

likelihood of finding all relevant studies. However, we

attempted to minimize the risk of missing relevant studies by

conducting an extensive search for gray literature, an extensive

hand search, and by contacting international experts within the

field of MDFT. Indeed, the large number of gray literature and

hand-searched literature that has been assessed for relevance

attests to this effort.

Conclusion

Although most of the few available studies on effectiveness are

characterized by methodological problems, the results of this

review suggest that MDFT seems to ‘‘work’’ in the sense that

Filges et al. 79

the intervention results, on average, in a slightly higher reduc-

tion in drug abuse for youth who received MDFT compared to

youth who received other active treatments. In addition to

knowledge of whether a certain intervention works, in the sense

that it is effective for the average individual, practitioners need

knowledge about potential differential effects on treatment.

Highly relevant participant characteristics, such as age, gender,

minority background, family composition (e.g., single parents),

and co-occurring conditions are potential predictors of treat-

ment outcome, and practitioners may need to tailor the program

to particular types of young drug abusers. Unfortunately, it was

not possible to examine which particular subgroups of youth

may be more likely to respond to specific interventions and

subsequently how treatments could be adapted or tailored to the

individual needs of a young person because there were not

enough studies to parse out more nuanced effects.

Programs for drug using youth are costly, and it is also pos-

sible that such initiatives have potential to cause harm to some

individuals. The available evidence points to small effect

sizes of MDFT in comparison to other treatments. Taking the

individual variation in treatment effects into consideration,

we cannot rule out the possibility that MDFT may be counter-

productive for some individuals. It is important to consider

the possibility of adverse effects of these interventions. The

popular belief is that MDFT and other family therapy

approaches are harmless, but very little research has been con-

ducted that focuses on the potential harm of such family ther-

apy approaches.

In addition to potential harm, it is crucial to learn more about

differential effectiveness and cost benefits of MDFT in order to

determine where money is best allocated as well as to under-

stand which, if any, youth benefit more or less than others. A

small body of evidence exists in relation to the treatment of

young drug abusers, with only a very modest number of con-

trolled evaluations of treatments for this group. Most of the few

available studies of effectiveness have methodological prob-

lems, such as small sample size and varied methods of asses-

sing drug abuse. Such problems make definitive conclusions

difficult. Well-designed, RCTs within this population are

needed and should be reported clearly in accordance with the

principles of the CONSORT 2010 statement (cite). In addition,

longer follow-up data should be available in future studies.

Acknowledgments

The review authors would like to thank Professor Barnaby Reeves

from the Cochrane Nonrandomized Studies Methods Group for mate-

rials and training regarding the assessment of the risk of bias in

NRCTs, the Campbell methods peer referees; Dr. William Turner and

Dr. Terry Pigott, Karianne Thune Hammerstrøm, and external content

and methods peer referees for valuable and insightful comments on

methods and content, during the stage of writing the protocol and the

final review report. We are grateful to external experts; Lori Whitten,

RTI International, and Professor Gayle Dakof, University of Miami

Miller School of Medicine, for their kind response and help in order

to capture potential studies that were not part of our own literature

search. Thanks to Head of SFI Campbell, Mette Deding, PhD, for con-

tinued support and efforts to realize this review. Last but not least,

thanks to the review team for their huge work morale, excellent colla-

boration, and perseverance throughout the entire review process.

Authors’ Note

This article is an abbreviated version of a systematic review approved

by the Campbell Collaboration. It was invited and accepted by the edi-

tor. The review authors take full responsibility for the content in this

publication.

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to

the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship,

and/or publication of this article.

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References denoted with * are the included studies. A reference

denoted with ** indicates the primary reference.

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