Article review

O R I G I N A L P A P E R

Co-morbid PTSD and suicidality in individuals with schizophrenia and substance and alcohol abuse

Nicholas Tarrier • Alicia Picken

Received: 14 December 2009 / Accepted: 27 July 2010 / Published online: 15 August 2010

� Springer-Verlag 2010

Abstract

Background Suicide risk is high in schizophrenic patients

and is further elevated in dual diagnosis patients. Suicide

behaviour is a continuum from ideation, plans to attempts.

Exposure to traumatic stress and co-morbid PTSD is ele-

vated in schizophrenic patients. Suicide behaviour is also

common in non-psychotic PTSD patients. This study aimed

to investigate the effect of trauma and co-morbid PTSD on

suicide behaviour in dual diagnosis patients and whether

co-morbid PTSD would further elevate suicide risk.

Method This was a cross-sectional study in which suicide

behaviour was compared in those with and without

co-morbid PTSD in 110 patients suffering schizophrenia

and alcohol and/or substance abuse.

Results 100 (91%) reported at least one traumatic event

with an average of 4.3 events. 31 (28%) patients met

criteria for full PTSD. Current suicidal ideation was

reported by 39 (35%) and 23 (21%) reported plans

and ideation, 69 (63%) reported at least one previous

suicide attempt. Suicide behaviour was significantly asso-

ciated with an increasing number of traumatic events.

Suicidality was significantly associated and elevated with

co-morbid PTSD. Analysis indicated that the effect of

trauma on suicide behaviour appeared to be mediated by

hopelessness.

Conclusions Suicide behaviour was not associated with

exposure to trauma per se but was associated with incre-

mental exposure to traumatic experiences. Consistent with

the study hypotheses, co-morbid PTSD further adds to the

risk of suicide behaviour in an already vulnerable group.

Keywords Schizophrenia � Dual diagnosis � PTSD � Trauma � Suicide behaviour

Introduction

The aim of this study was to investigate whether co-morbid

PTSD was associated with increased suicide behaviour in a

sample of patients suffering schizophrenia with already

elevated vulnerability to suicide risk by nature of co-morbid

substance and alcohol abuse.

Suicide risk in schizophrenia is high, and is a significant

public health concern and a major cause of premature death

[13, 14, 21]. Most recent estimates indicate 4.9% of

schizophrenic patients will commit suicide during their

lifetime [43]. Suicidal ideation and planning are important

steps that lead to self-harm and may lead to death or hospi-

talisation [10, 27, 33]. Suicidal ideation and attempts are

common with as many as half of all patients with schizo-

phrenia experiencing suicidal ideation at any point in time or

having a history of suicide attempts [21, 22, 26, 33, 42, 54], as

well as increasing the risk for completed suicide the expe-

rience of frequent suicidal ideation leading to plans, intent

and attempts are themselves clinically important and con-

stitute cognitive, emotional and behavioural aspects of

suicide behaviour [12, 28]. The term ‘suicide behaviour’

subsumes a continuum from suicide ideation through plan-

ning, intent and attempts that may or may not lead to com-

pleted suicide [12]. Although the majority of those who

experience suicide ideation do not go onto successfully

complete suicide, all aspects of the suicide behaviour con-

tinuum are considered to have clinical importance [28].

N. Tarrier (&) � A. Picken Division of Clinical Psychology, School of Psychological

Sciences, University of Manchester, Zochonis Building,

Oxford Road, Manchester M13 9PL, UK

e-mail: [email protected]

123

Soc Psychiatry Psychiatr Epidemiol (2011) 46:1079–1086

DOI 10.1007/s00127-010-0277-0

Suicide risk has been associated with a wide range of

factors, including depression, hopelessness, low self-

esteem, insight, substance misuse, persistent psychotic

symptoms, agitation or motor restlessness, fear of mental

deterioration, poor adherence to treatment and recent loss

[10, 17, 19, 27, 54, 55]. Hopelessness is one of the most

consistently identified risk factors for suicidal behaviour

[16, 54] and is associated with suicide risk independently

of depression [18].

Estimates of co-morbid substance abuse in schizo-

phrenic patients are high, between almost 50 and 65% [15,

50]. Even low levels of substance misuse have been shown

to have a detrimental effect on clinical outcome [15]. The

most frequently reported substance used being alcohol, and

cannabis the most frequently used drug [5, 11, 29, 58].

Consistent results indicate frequent poly-substance use,

the most common combination being alcohol and cannabis

[5, 29]. There are strong indications that outcomes,

including elevated risk of suicidal behaviour are poorer for

those people with schizophrenia who abuse drugs and

alcohol [20, 27, 36].

There is a strong indication that suicide behaviour is

high in non-psychotic PTSD patients [53]. In a recent

review of 65 studies in which assessments of PTSD and

suicide behaviour were available there was a clear rela-

tionship between PTSD and suicidal thoughts and behav-

iours irrespective of the type of trauma experienced or how

the sample was recruited [44]. Thus, there is evidence that

PTSD in general is associated with elevated suicidal

behaviour. The question arises as to whether co-morbid

PTSD in schizophrenic patients would further elevate sui-

cide risk. Exposure to trauma in those suffering schizo-

phrenia appears higher than in the general population with

estimates of over 90% of having suffered at least one

traumatic event [24, 32, 39, 45]. Those diagnosed with

schizophrenia and psychotic disorders are not only more

likely to be exposed to traumatic events, but they are also

more likely to suffer from PTSD as a result. Prevalence

rates of PTSD in patients suffering from severe mental

illness are reported ranging from 14 to 43% [39, 41, 49, 56]

as compared to rates of PTSD in the general population

which are estimated at 1–14% for lifetime prevalence

(APA 1995, p. 437). PTSD in patients suffering schizo-

phrenia and other psychotic disorders may result from their

exposure to external traumatic events. There are also

increasing accounts in the literature of PTSD resulting

from the experience of the symptoms of the illness them-

selves [34, 37, 38] that is a response to an internal event.

There are numerous conceptual and practical difficulties in

diagnosing PTSD in patients suffering from psychosis [51,

52]. In spite of these difficulties Mueser et al. [40]

reviewed the evidence for the reliability and validity of the

assessment of trauma and PTSD in those suffering from

severe mental illness and concluded that such assessment

could be performed rigorously.

The current study was carried out to investigate whether

co-morbid PTSD would be associated with an increase in

suicide behaviour in a sample with elevated risk as a result

drug and/or alcohol abuse. Specifically, we hypothesised

that those suffering co-morbid PTSD would show signifi-

cantly greater levels of suicide behaviour than those

without co-morbid PTSD.

Method

Participants

This study opportunistically recruited patients who were

participating in a multi-centred clinical trial of motiva-

tional-CBT (the MIDAS trial, see [5]). Only those partic-

ipants in the study sites in the north west of England were

recruited. 110 participants were recruited from 4 NHS

trusts in the north west of England between October 2004

and April 2007. Participants were first recruited into the

clinical trial and consented to further assessment for the

purposes of this study. Assessments were carried out at the

6-month assessment point of the trial. Ethical permission

was obtained from the NHS Eastern MREC. Participants

were recruited into the study if they met the following

inclusion criteria: (1) DSM-IV diagnostic criteria for

schizophrenia, schizophreniform or schizoaffective disor-

der, (2) were English speaking, (3) had contact with mental

health services, (4) were able to give informed consent and

(5) met minimum levels of substance use of 28 units of

alcohol and/or using drugs on at least 2 days a week, in at

least half of the weeks of the past three months and met

criteria for dependence or abuse assessed by the Structured

Clinical interview for DSM. Participants were excluded if

there was an organic cause for their psychosis. All partic-

ipants were living in the community at the time of

recruitment and had current contact with mental health

services; they were referred to the study by their care

coordinators.

Measures

Positive and Negative Symptom Scale (PANSS)

The PANSS [30] was used as a measure of severity of

schizophrenia. The PANSS is a semi-structured interview

which assesses positive, negative and general symptoms

using a 7-point rating scale over 30 items. Kay et al. [31]

demonstrated that the PANSS had good psychometric

properties. It is commonly used measure in schizophrenia

research.

1080 Soc Psychiatry Psychiatr Epidemiol (2011) 46:1079–1086

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Calgary Depression Scale (CDS)

The CDS [1] is a 9-item semi-structured interview

designed for use with individuals with a diagnosis of

schizophrenia. The scale assesses levels of depressive

symptoms independent of positive and negative symptoms

of schizophrenia and any effects of medication. The scale

has good psychometric properties [1–3].

Beck Hopelessness Scale (BHS)

The BHS [9] was used as a secondary measure of suicide

risk. The BHS assesses both the presence of negative future

expectancies and lack of positive future expectancies and

predicts suicide and non-fatal self-harm [35]. Respondents

agree, true or false with 20 statements, responses are scored

0 or 1. The range of scores is from 0 to 20. The scale has

good psychometric properties [9] and has been used with

psychiatric outpatients [7]. McMillan et al. [35] in a meta-

analysis of studies which had utilised the BHS found that

the standard cutoff point for the BHS, scores of 14 and

above, identified those at risk of self-harm and a group with

higher risk of suicide, sensitivity was 0.78 and 0.80,

respectively. In a sample of individuals with first episode

schizophrenia, the mean score on the BHS was 7.6, stan-

dard deviation 4.1.

Beck Suicide Scale (BSS)

The BSS [8] was used as the primary outcome measure of

suicide behaviour. It is a 21-item scale in which each item

is scored on three points (0, 1 or 2). The first five items

consist of screening questions and are completed by all

individuals. Items 4 and 5 indicate current desire for sui-

cide. If the individual scores 0 on these two items then they

omit items on ideation and plans and complete questions

regarding previous attempts. Individuals who respond

positively to items 4–5 are asked further questions to

determine their level of risk. Pinninti et al. [46] demon-

strated that the BSS had good psychometric properties

when used with patients with schizophrenia. The BSS

significantly discriminated between those who had previ-

ous attempts and those who had never attempted suicide

and also identified those who were still considered a sui-

cide risk.

Posttraumatic Stress Diagnostic Scale (PDS)

The presence of PTSD was assessed using the PDS [23].

The structure and content of the PDS mirror the DSM-IV

diagnostic criteria for PTSD. The participants rated on a

0–3 scale on how much each PTSD symptom has bothered

them in the last 3 months. In the first instance, respondents

were asked to read through a list of traumatic events and to

mark any event they had witnessed or experienced. Owing

to recent findings [56] indicating traumas specific to the

schizophrenia population, such as involuntary hospitalisa-

tion, distressing psychotic symptoms and treatments, these

experiences were also added to the list of traumatic expe-

riences. They were then asked which of the experiences

had affected them the most and to briefly describe the

event. This event is the index event which is referred to

when asking about resulting posttraumatic symptoms. They

were asked questions to ascertain whether the index event

met criterion A for PTSD diagnoses. These refer to whether

a person’s life was in danger, they were physically injured,

felt threatened or helpless. The PDS has good psychometric

properties [23]. The PDS showed good consistency with a

semi-structured interview the Clinician Administered

PTSD Scale for Schizophrenia [25] in a subsample [45].

Procedure

Participants were referred and screened for eligibility (see

[5] for further procedural details). During baseline assess-

ments for the MIDAS study, demographic information was

collected and the PANSS was carried out and individuals

were randomised into the intervention or control arm. At

6-month follow-up, participants completed the CDS, BHS,

BSS and PDS measures for the present study. All measures

were administered in a single session by trained research

assistants.

All research assistants who administered the PANSS

were fully trained before assessing any participants and

compared to a ‘gold standard’ expert assessor. Interclass

correlations between each assessor and the gold standard

were calculated and the means were 0.89, 0.84, 0.83 and

0.84 for the positive, negative and general subscales and

total PANSS scores, respectively. These scores demon-

strate good inter-rater reliability.

Statistical analysis

Appropriate non-parametric tests were used throughout

when data were not normal and could not be transformed.

Kruskall–Wallis and Mann–Whitney tests were used to

examine differences in suicide scores between those who

reported PTSD and those who did not and also between

individuals reporting different index events. Spearman’s

correlations were carried out to examine associations

between suicide scores and a variety of demographic and

psychological characteristics before logistic regression

analysis were carried out to identify predictor variables for

suicidality. A meditational analysis was performed on the

effect of hopelessness (the mediator) on the relationship of

traumatic stress (IV, the independent variable) on suicide

Soc Psychiatry Psychiatr Epidemiol (2011) 46:1079–1086 1081

123

behaviour (DV, the dependent variable). Conventionally in

a meditational analysis, it is necessary to show that the IV

predicts the DV, the IV predicts the mediator, the mediator

predicts the DV, but the IV does not predict the DV when

the effects of the mediator are controlled [4]. The boot-

strapping method of mediational analysis was used to

assess variables that mediate the relationship between

PTSD severity and suicidality. The bootstrapping method

is preferable to other methods of mediational analysis as it

does not make assumptions of normality in the data used

and has been recommended for use in small samples.

Preacher and Hayes [48] method was used to calculate the

effects of posttraumatic stress on suicidality as mediated by

hopelessness.

Results

From a total of 166 potentially eligible participants from

the Manchester trial centre, 126 individuals consented to

the study and 110 completed the assessments.

Sample characteristics

The characteristics of the sample with and without PTSD

are presented in Table 1.

Prevalence of suicidality

Current suicidal ideation was reported by 39 (35%) patients

and 23 (21%) reported both plans and ideation. At least one

previous suicide attempt was reported by 69 (63%) indi-

viduals with 62 (89%) reporting that at the time of the

attempt their wish to die was moderate or high.

The mean BSS total score was 5.62 (SD 7.44, median 3,

range 0–34) for the whole sample. In the subsample of

ideators, the mean was 13.15 (SD 7.98, median 12, range

3–34) and in non-ideators the mean was 1.48 (SD 1.62,

median 0, range 0–4). Individuals were categorised into

whether they reported suicidal ideation or not, reported

plans or not and whether they have attempted suicide in the

past. The BSS scores for the total sample are in agreement

with those reported by Pinninti et al. [46], whereas the

scores for the 35% who reported ideation are in agreement

with those reported by Beck and Steer [6] for a similar

population.

Occurrence of traumatic events and PTSD

One hundred of the 110 (91%) participants reported at least

one event with an average of 4.3 events and 31 (28%) met

full criteria for PTSD. Comparisons between the group

(PTSD and non-PTSD) indicated that scores on the total

PANSS, positive and general subscales, Calgary Depres-

sion Scale, Beck Hopelessness Scale and Beck Suicide

Scale were significantly higher in the PTSD group. There

were no other significant differences between the two

groups (see Table 1 for characteristics of the PTSD and

non-PTSD groups) (these results are presented in detail in

Picken and Tarrier [45].

Relationship between co-morbid PTSD and suicide

behaviour

The PTSD group reported significantly more suicidal ide-

ation plans and behaviour (median 6) as measured by the

BSS than those without PTSD (median 2: U = 673,

p \ 0.01) (see Table 1). There were significant associa- tions between suicide behaviour, as measured by the BSS,

and the number of traumatic events (q = 0.25, p \ 0.01) and the severity of PTSD symptoms (q = 0.41, p \ 0.01) (see Table 2). Mann–Whitney tests were carried out for

paired comparison for the four different types of events no

significant differences were found.

Predictor variables for suicidal ideation, plans

and behaviour

Analyses were carried out to identify predictor variables

for the presence of suicide risk. First, Spearman’s corre-

lations were calculated between suicide risk as measured

by the BSS, psychological variables and sample charac-

teristics. These correlations are given in Table 2.

Only depression, hopelessness, number of events expe-

rienced and total PTSD symptom severity were signifi-

cantly associated with suicide scores.

A logistic regression was then performed using the

significant variables in the first regression block and all

other variables in the second block. A dichotomous vari-

able was created of those participants who reported current

ideation and plans vs. no current ideation or plans, 39

individuals versus 71, respectively.

Hopelessness (B = 0.21, SE = 0.07, p = 0.00,

Exp(B) = 1.23) was the only significant predictor, with, as

expected, increases in hopelessness being associated with

greater levels of current suicidal ideation and plans.

Mediation

In the mediational analysis the independent variable was

the scores on the PDS (traumatic stress), the dependent

variable was BSS scores, for ideation and plans but not past

behaviour (suicide behaviour) and the mediator was BHS

scores (hopelessness). To demonstrate the mediating effect

of hopelessness on the relationship between traumatic

stress and suicide behaviour, it was necessary to

1082 Soc Psychiatry Psychiatr Epidemiol (2011) 46:1079–1086

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demonstrate that (1) the PDS was significantly associated

with suicide behaviour, (2) the PDS was significantly

associated with the BHS, (3) the BHS was significantly

associated with suicide behaviour, (4) the association

between the PDS and suicide behaviour was non-significant

or greatly reduced when the effects of the BHS were

controlled. These conditions were demonstrated (see

Table 3).

The relationship between PDS and BSS was found to be

highly significant when frequency or severity of PTSD

symptoms were considered. However, when the effect of

hopelessness was controlled for the relationship was no

Table 1 Sample characteristics of the total sample and divided

into those with and without

PTSD

* p \ 0.01

PTSD (n = 31) Non-PTSD (n = 79) Total sample (n = 110)

Gender

Male 30 (97%) 69 (87%) 99 (90%)

Female 1 (3%) 10 (13%) 11 (10%)

Age

Mean (SD) 36 (9.33) 39 (10.20) 38 (10.00)

Median 34 38 37

Range 20–52 18–61 18–61

Ethnicity

White 29 (94%) 71 (90%) 100 (91%)

Black Caribbean 0 2 (2.5%) 2 (2%)

Black Other 0 2 (2.5%) 2 (2%)

Indian 0 1 (1%) 1 (1%)

Pakistani 0 1 (1%) 1 (1%)

Other 2 (6%) 2 (2.5%) 4 (4%)

Diagnosis

Schizophrenia 28 (90%) 59 (75%) 87 (79%)

Schizoaffective 1 (3%) 12 (15%) 13 (12%)

Schizophreniform 0 1 (1%) 1 (1%)

Psychosis NOS 2 (7%) 7 (9%) 9 (8%)

Years since onset

Mean (SD) 11 (8.34) 14 (10.65) 13 (10.14)

Hospitalisations

Mean (SD) 4 (5.79) 3 (3.02) 4 (3.00)

Substance

Alcohol 17 (55%) 46 (58%) 63 (57%)

Cannabis 8 (26%) 21 (27%) 29 (26%)

Crack cocaine 2 (6%) 3 (4%) 5 (5%)

Heroin 0 2 (2%) 2 (2%)

Amphetamine 4 (13%) 7 (9%) 11 (10%)

PANSS scores

Positive: mean (SD) 18.2 (4.7)* 15.6 (5.4)* 16.6 (5.3)

Negative: mean (SD) 13.7 (3.7) 14.3 (4.9) 14.1 (4.6)

General: mean (SD) 36.2 (7.5)* 31.7 (6.8)* 33.5 (7.3)

Total score: mean (SD) 67.4 (11.2)* 60.2 (13.3)* 62.7 (13.0)

CDS

Mean (SD) 9.7 (5.7)* 4.7 (4.4)* 6.1 (5.3)

BHS

Mean (SD) 11.1 (6.2)* 6.8 (4.8)* 8.0 (5.6)

BSS

Mean (SD) 9.5 (8.5)* 4.1 (6.4)* 5.6 (7.4)

Median (range) 5 (0–27)* 2 (0–34)* 3 (0–34)

Soc Psychiatry Psychiatr Epidemiol (2011) 46:1079–1086 1083

123

longer significant. Therefore, the results from the media-

tional analysis, using a bootstrapping method, indicate that

the impact that PDS has on suicidal ideation and plans is

mediated by hopelessness.

Discussion

The reported exposure to trauma in this population is very

high, 91% reporting at least 1 traumatic event with an

average of 4.3 events being experienced. Full criterion for

PTSD was met by 31 (28%) of participants [45]. These

rates are largely consistent with those found in similar

studies (e.g. [32, 39]). Although our conclusions from these

data, reported elsewhere, were that this rate may well be

inflated by behaviour and experiences related to the

patients’ psychotic illness [45]. Notwithstanding the nature

of the traumatic stress, the clinical impact of trauma

appears profound.

The study hypothesis was confirmed in that those

patients identified as suffering co-morbid PTSD had sig-

nificant greater levels of suicide behaviour, in terms of

suicidal ideation, plans and attempts than those without

co-morbid PTSD. This was irrespective of the severity of

the psychotic illness. Furthermore, there was a significant

positive association between suicidal behaviour as assessed

on the BSI and posttraumatic symptoms. Further analysis

indicated that the significant association between post-

traumatic stress and suicide behaviour was mediated by

hopelessness. The experience of a trauma in itself does not

appear to be associated with an increase in suicide

behaviour, since the vast majority of the non-PTSD group

had experienced at least one traumatic event, although the

experience of incremental events is associated with

increased suicidal behaviour.

Factors influencing suicidal behaviour may act through a

number of possible pathways [12]. They may be transdi-

agnostic and common mechanisms operating in all disor-

ders. There may be factors that are disorders specific and

particular to schizophrenia, or there may be disorder-

specific factors that operate in schizophrenia because of a

co-morbid association, such as the effects of depression or

more probably hopelessness. This study was designed to

test the hypothesis that co-morbid PTSD increased suicide

behaviour rather than mutually excluding these different

pathways. However, some investigation of the mechanism

or pathway to suicide behaviour has been possible. It

appears that co-morbid PTSD is associated with increased

suicide behaviour and this may operate through hopeless-

ness. Thus, it may be that hopelessness is common in

schizophrenia and given the nature of the disorder and

associated disability this is understandable. The abuse of

drugs and alcohol may be indicative of hopelessness or add

to it and it is further incremented by the experience of

trauma and subsequent PTSD.

We have previously advanced the theory that suicide

behaviour is a result of information bias, faulty appraisal

and suicide schema (This has been formulated in the

Schematic Appraisal Model of Suicide, SAMS; [28]). The

experience of trauma may affect the cognitive architecture,

so as to increase suicide risk by increasing information

processing bias and appraisal or evaluative judgements of

the present and the future as being negative, threatening

and aversive. This in combination with a belief of the

ineffectiveness of personal agency to change the situation

currently or in the future and the absence of rescue from

others, or lack of access to social resources who could

provide effective rescue or assistance, may result in

Table 2 Correlations between BSS scores and other key variables

q

Age -0.08

Ethnicity -0.04

Living arrangements -0.15

Diagnosis 0.9

Days abstinent 0.04

Most problematic substance -0.1

Number of hospitalisations -0.07

Years since onset -0.07

Depression scores 0.6*

Hopelessness scores 0.5*

Total number of events 0.25*

PTSD symptom severity 0.41*

* p \ 0.01

Table 3 Regression pathways for mediational analysis of PDS

frequency, BHS scores and

suicidal ideation and plans

Pathway Coefficient Standard

error

t value p value

1. PDS frequency predicts suicidal ideation and plans 0.16 0.05 3.51 0.01

2. PDS frequency predicts BHS scores 0.14 0.04 3.69 0.01

3. BHS scores predicts suicidal ideation and plans

(controlling for PDS frequency)

0.7 0.1 7.26 0.01

4. PDS frequency predicts suicidal ideation and plans

(controlling for BHS scores)

0.06 0.04 1.59 0.11

1084 Soc Psychiatry Psychiatr Epidemiol (2011) 46:1079–1086

123

appraisals of being defeated, trapped and hopeless. A bias

in information search and selection and in interpretation

would establish and reinforce such an appraisal system.

Subsequently, suicide as an escape strategy or suicide

schema becomes established and further elaborated and

such a suicide schema incorporates stimulus, response,

emotional, behavioural and cognitive elements and when

activated increases the probability of suicide behaviour

being initiated [57]. It is hypothesised that factors, such as

emotional reactivity or dysregulation are more likely to

result in schema elaboration and activate the suicide

schema and thus be associated with increased levels of

suicide behaviour [47, 57]. It would therefore be predicted

on the basis of the SAMS model that co-morbid PTSD

would be associated with suicide behaviour due to the

elevated levels of arousal, physiological reactivity and

psychological distress which are constituent parts of the

disorder.

This study has a number of strengths and limitations.

The sample is of a reasonable size and represented a group

of elevated suicide risk by their substance abuse. Potential

limitations include: substance use was heterogeneous and

included both drug and alcohol consumption, although this

factor did not appear to influence the results; there was no

comparison with patients who were not abusing substances;

and, the study was cross-sectional in its data collection.

The latter limitation has to be balanced against the higher

levels of attrition and difficulty of interpretation in longi-

tudinal data. Although the mediation model was supported,

we cannot be absolutely confident that other factors were

not influential in determining suicide behaviour.

Acknowledgments This research was funded by the Medical Research Council, UK as an ‘add on’ study to the MIDAS—Moti- vational Interventions for Drug and Alcohol misuse in Schizophrenia trial (Principal Investigator: Christine. Barrowclough; Co-Investiga-

tors: Tom Craig, Linda Davies, Graham Dunn, Gillian Haddock, Shon

Lewis, Jan Moring, John Strang, Nicholas Tarrier and Til Wykes) and

was submitted by Dr Picken in part fulfil of the requirement for a PhD

in the School of Psychological Sciences, Faculty of Medical and

Human Sciences, University of Manchester.

References

1. Addington D, Addington J, Maticka-Tyndale E (1992) Reliability

and validity of a depression rating scale for schizophrenics.

Schizophr Res 6:201–208

2. Addington D, Addington J, Maticka-Tyndale E (1994) Specificity

of the Calgary Depression Scale. Schizophr Res 11:239–244

3. Addington D, Addington J, Atkinson M (1996) A psychometric

comparison of the Calgary Depression Scale for Schizophrenia

and the Hamilton Depression Rating Scale. Schizophr Res

19:205–212

4. Baron RM, Kenny DA (1986) The moderator-mediator variable

distinction in social psychological research: Conceptual, strategic

and statistical considerations. J Pers Soc Psychol 51:1173–1182

5. Barrowclough C, Haddock G, Beardmore R, Conrod P, Craig T,

Davies L, Dunn G, Lewis S, Moring J, Tarrier N, Wykes T (2009)

Evaluating integrated MI and CBT for people with psychosis and

substance misuse: recruitment, retention and sample character-

istics of the MIDAS trial. Addictive Behav (in press)

6. Beck AT, Steer RA (1993) Beck Scale for Suicide Ideation.

Harcourt Brace, San Antonio

7. Beck AT, Brown G, Berchick RJ, Stewart BL, Steer RA (1990)

Relationship between hopelessness and ultimate suicide: a repli-

cation with psychiatric outpatients. Am J Psychiatry 147:190–195

8. Beck AT, Kovacs M, Weissman A (1979) Assessment of suicidal

intention: the scale for suicide ideation. J Consult Clin Psychol

47:343–352

9. Beck AT, Weissman A, Lester D, Trexler L (1974) The mea-

surement of pessimism: the hopelessness scale. J Consult Clin

Psychol 42:861–865

10. Bertelsen M, Jeppesen P, Petersen L, Thorup A, Ohlenschlaeger

J, Le Quach P, Christensen TO, Jorgensen P, Nordentoft M

(2007) Suicidal behaviour and mortality in first episode psycho-

sis: the OPUS trial. Br J Psychiatry 191(Suppl 51):140–146

11. Blanchard J, Brown SA, Horan WP, Sherwood AR (2000) Sub-

stance use disorders in schizophrenia: review, integration, and a

proposed model. Clin Psychol Rev 20(2):207–234

12. Bolton C, Gooding P, Kapur N, Barrowclough C, Tarrier N

(2007) Developing psychological perspectives of suicidal

behaviour and risk in people with a diagnosis of schizophrenia:

we know they kill themselves but do we understand why? Clin

Psychol Rev 27:511–536

13. Brown S (1997) Excessive mortality of schizophrenia. A meta-

analysis. Br J Psychiatry 171(12):502–508

14. Caldwell C, Gottesman I (1990) Schizophrenics kill themselves

too: a review of risk factors. Schizophr Bull 16(4):571–589

15. Cleary M, Hunt GE, Matheson SL, Siegfried N, Walter G (2008)

Psychosocial interventions for people with both severe mental

illness and substance misuse. Cochrane Database Syst Rev (1).

Art. No.: CD001088. doi:10.1002/14651858.CD001088.pub2

16. Conner KR, Duberstein PR, Conwell Y, Seidlitz L, Caine ED

(2001) Psychological vulnerability to completed suicide: a review

of empirical studies. Suicide Life Threat Behav 31(4):367–385

17. Crumlish N, Whitty P, Kamali M, Clarke M, Browne S, McTigue

O, Lane A, Kinsella C, O’Callaghan E (2005) Early insight

predicts depression and attempted suicide after 4 years in first-

episode schizophrenia and schizophreniform disorder. Acta

Psychiatr Scand 112:449–455

18. Drake RE, Cotton PG (1986) Depression, hopelessness and

suicide in chronic schizophrenia. Br J Psychiatry 148:554–559

19. Drake RE, Gates C, Whitaker A, Cotton PG (1985) Suicide

among schizophrenics: a review. Compr Psychiatry 26:90–100

20. Drake RE, Mueser KT (2000) Psychosocial approaches to dual

diagnosis. Schizophr Bull 26(1):105–118

21. Fenton WS, McGlashan TH, Victor BJ, Blyler CR (1997)

Symptoms, subtype and suicidality in patients with schizophrenia

spectrum disorders. Am J Psychiatry 154:199–204

22. Fenton WS (2000) Depression, suicide and suicide prevention in

schizophrenia. Suicide Life Threat Behav 30:34–49

23. Foa EB, Cashman L, Jaycox L, Perry K (1997) The validation of

a self-report measure of posttraumatic stress disorder: the Post-

traumatic Diagnostic Scale. Psychol Assess 9:445–451

24. Frame L, Morrison AP (2001) Causes of posttraumatic stress

disorder in psychotic patients. Arch Gen Psychiatry

58(3):305–306

25. Gearon JS, Bellack AS, Tenhula WN (2004) Preliminary reli-

ability and validity of the clinician-administered PTSD scale for

schizophrenia. J Consult Clin Psychol 72:121–125

26. Harkavy-Friedman JM, Kimhy D, Nelson EA, Venarde DF,

Malaspina D, Mann JJ (2003) Suicide attempts in schizophrenia:

Soc Psychiatry Psychiatr Epidemiol (2011) 46:1079–1086 1085

123

the role of command auditory hallucinations for suicide. J Clin

Psychiatry 64(8):871–874

27. Hawton K, Sutton L, Haw C, Sinclair J, Deeks JJ (2005)

Schizophrenia and suicide: systematic review of risk factors. Br J

Psychiatry 187:9–20

28. Johnson J, Gooding P, Tarrier N (2008) Suicide risk in schizo-

phrenia: explanatory models and clinical implications: the sche-

matic appraisal model of suicide (SAMS). Psychol Psychother

81:55–77

29. Kavanagh DJ, Waghorn G, Jenner L, Chant DC, Carr V, Evans

M, Herrman H, Jablesnsky A, McGrath J (2004) Demographic

and clinical correlates of comorbid substance use disorders in

psychosis: multivariate analyses from an epidemiological sample.

Schizophr Res 66:115–124

30. Kay SR, Opler LA, Lindenmayer JP (1987) The Positive and

Negative Syndrome Scale (PANSS) for schizophrenia. Schizophr

Bull 13:261–276

31. Kay SR, Opler LA, Lindenmayer JP (1988) Reliability and

validity of the positive and negative syndrome scale for schizo-

phrenia. Psychiatry Res 23:99–110

32. Kilcommons AM, Morrison AP (2005) Relationships between

trauma and psychosis: an exploration of cognitive and dissocia-

tive factors. Acta Psychiatr Scand 112(5):351–359

33. Kontaxakis V, Havaki-Kontaxaki B, Margariti M, Stamouli S,

Kollias C, Christodoulou G (2004) Suicidal ideation in inpatients

with acute schizophrenia. Can J Psychiatry 49:476–479

34. McGorry PD, Chanen A, McCarthy E, Van Riel R, McKenzie D,

Singh B (1991) Posttraumatic stress disorder following recent

onset psychosis: An unrecognized postpsychotic syndrome.

J Nerv Ment Dis 179:253–258

35. McMillan D, Gilbody S, Beresford E, Neilly L (2007) Can we

predict suicide and non-fatal self-harm with the Beck Hopeless-

ness Scale? A meta-analysis. Psychol Med 37:769–778

36. Margolese HC, Malchy L, Negrete JC, Tempier R, Gill K (2004)

Drug and alcohol use among patients with schizophrenia and

related psychoses: levels and consequences. Schizophr Res

67:157–166

37. Meyer H, Taiminen T, Vuori T, Aijala A, Helenius H (1999)

Posttraumatic stress disorder symptoms related to psychosis and

acute involuntary hospitalization in schizophrenic and delusional

patients. J Nerv Ment Dis 187(6):343–352

38. Morrison AT, Frame L, Larkin W (2003) Relationships between

trauma and psychosis: a review and integration. Br J Clin Psychol

42:331–354

39. Mueser KT, Goodman LB, Trumbetta SL, Rosenberg SD, Osher

FC, Vidaver R, Auciello P, Foy DW (1998) Trauma and post-

traumatic stress disorder in severe mental illness. J Clin Consult

Psychol 66:493–499

40. Mueser KT, Slayers MP, Rosenberg SD, Ford JD, Fox L, Carty P

(2001) Psychometric evaluation of trauma and posttraumatic

stress disorder assessments in persons with severe mental illness.

Psychol Assess 13(1):110–117

41. Mueser KT, Rosenberg SD, Jankowski MK, Hamblen J,

Descamps M (2004) A cognitive-behavioural treatment program

for posttraumatic stress disorder in persons with severe mental

illness. Am J Psychiatr Rehabil 7:107–146

42. Nieto E, Vieta E, Gasto C, Vallejo J, Cirera E (1992) Suicide

attempts of high medical seriousness in schizophrenic patients.

Compr Psychiatry 33(6):384–387

43. Palmer BA, Prankratz VS, Bostwick JM (2005) The lifetime risk

of suicide in schizophrenia: a reexamination. Arch Gen Psychi-

atry 62(3):247–253

44. Panagioti M, Gooding P, Tarrier N (2009) Post-traumatic stress

disorder and suicidal behaviour: a narrative review. Clin Psychol

Rev 29:471–482

45. Picken A, Tarrier N (2010) Trauma and co-morbid PTSD in

individuals with schizophrenia and substance abuse. (submitted

for publication)

46. Pinninti N, Steer RA, Rissmiller DJ, Nelson S, Beck AT (2002)

Use of the Beck Scale for Suicide Ideation with psychiatric

inpatients diagnosed with schizophrenia, schizoaffective or

bipolar disorder. Behav Res Ther 40:1071–1080

47. Pratt D, Gooding P, Johnson J, Taylor P, Tarrier N (2010) Suicide

schemas in non-affective psychosis: an empirical investigation.

(submitted for publication)

48. Preacher KJ, Hayes AF (2004) SPSS and SAS procedures for

estimating indirect effects in simple mediation models. Behav

Res Methods Instrum Comput 36(4):717–731

49. Priebe S, Broker M, Gunkel S (1998) Involuntary admission and

posttraumatic stress disorder symptoms in schizophrenia patients.

Compr Psychiatry 39(4):220–224

50. Regier DA, Farmer ME, Rae DS, Locke BZ, Keith SJ, Judd LL,

Goodwin FK (1990) Comorbidity of mental disorders with

alcohol and other drug abuse. Results from the Epidemiologic

Catchment Area (ECA) Study. J Am Med Assoc 264:2511–2518

51. Seedat S, Stein MB, Oosthuizen PP, Emsley RA, Stein DJ (2003)

Linking posttraumatic stress disorder and psychosis. A look at

epidemiology, phenomenology and treatment. J Nerv Ment Dis

191:675–681

52. Tarrier N (2005) Co-morbidity and associated clinical problem in

schizophrenia: their nature and implications for comprehensive

cognitive-behavioural treatment. Behav Change 22:125–142

53. Tarrier N, Gregg L (2004) Suicide risk in civilian PTSD patients:

predictors of suicidal ideation, planning and attempts. Soc

Psychiatry Psychiatr Epidemiol 39:655–661

54. Tarrier N, Barrowclough C, Andrews B, Gregg L (2004) Suicide

risk in recent onset schizophrenia: the influence of clinical.

Social, self-esteem and demographic factors. Soc Psychiatry

Psychiatr Epidemiol 39:927–937

55. Tarrier N, Haddock G, Lewis S, Drake R, Gregg L, The Socrates

Trial Group (2006) Suicide behaviour over 18 months in recent

onset schizophrenic patients: the effects of CBT. Schizophr Res

83:15–27

56. Tarrier N, Khan S, Cater J, Picken A (2007) The subjective

consequences of suffering a first episode psychosis: trauma and

suicide behaviour. Soc Psychiatry Psychiatr Epidemiol 42:29–35

57. Tarrier N, Gooding P, Gregg L, Johnson J, Drake R, The Socrates

Trial Group (2007) Suicide schema in schizophrenia: the effect of

emotional reactivity, negative symptoms and schema elaboration.

Behav Res Ther 45:2090–2092

58. Weaver T, Madden P, Charles V, Stimson G, Renton A, Tyrer P

et al (2003) Comorbidity of substance misuse and mental illness

in community mental health and substance misuse services. Br J

Psychiatry 183:304–313

1086 Soc Psychiatry Psychiatr Epidemiol (2011) 46:1079–1086

123

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