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The Hamilton Depression Rating Scale: Has the

Gold Standard Become a Lead Weight?

ARTICLE in AMERICAN JOURNAL OF PSYCHIATRY · JANUARY 2005

Impact Factor: 12.3 · DOI: 10.1176/appi.ajp.161.12.2163 · Source: PubMed

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Am J Psychiatry 161:12, December 2004 2163

Reviews and Overviews

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The Hamilton Depression Rating Scale: Has the Gold Standard Become a Lead Weight?

R. Michael Bagby, Ph.D.

Andrew G. Ryder, M.A.

Deborah R. Schuller, M.D.

Margarita B. Marshall, B.Sc.

Objective: The Hamilton Depression Rat- ing Scale has been the gold standard for the assessment of depression for more than 40 years. Criticism of the instrument has been increasing. The authors review studies pub- lished since the last major review of this in- strument in 1979 that explicitly examine the psychometric properties of the Hamil- ton depression scale. The authors’ goal is to determine whether continued use of the Hamilton depression scale as a measure of treatment outcome is justified.

Method: MEDLINE was searched for stud- ies published since 1979 that examine psychometric properties of the Hamilton depression scale. Seventy studies were identified and selected, and then grouped into three categories on the basis of the major psychometric properties exam- ined—reliability, item-response character- istics, and validity.

Results: The Hamilton depression scale’s internal reliability is adequate, but many scale items are poor contributors to the measurement of depression severity; oth- ers have poor interrater and retest reliabil- ity. For many items, the format for re- sponse options is not optimal. Content validity is poor; convergent validity and discriminant validity are adequate. The factor structure of the Hamilton depres- sion scale is multidimensional but with poor replication across samples.

Conclusions: Evidence suggests that the Hamilton depression scale is psychomet- rically and conceptually flawed. The breadth and severity of the problems mil- itate against efforts to revise the current instrument. After more than 40 years, it is time to embrace a new gold standard for assessment of depression.

(Am J Psychiatry 2004; 161:2163–2177)

The Hamilton Depression Rating Scale (1) was devel- oped in the late 1950s to assess the effectiveness of the first generation of antidepressants and was originally pub- lished in 1960. Although Hamilton (1) recognized that the scale had “room for improvement” (p. 56) and that further revision was necessary, the scale quickly became the stan- dard measure of depression severity for clinical trials of antidepressants (2, 3). The Hamilton depression scale has retained this function and is now the most commonly used measure of depression (3). Our objective in this arti- cle is to provide a review of the Hamilton depression scale literature published since the last major evaluation of its psychometric properties, more than 20 years ago (4). More recent reviews have appeared (3, 5–7), but they have not systematically examined the literature with regard to a broad range of measurement issues. Significant develop- ments in psychometric theory and practice have been made since the 1950s and need to be applied to instru- ments currently in use. We evaluate the Hamilton depres- sion scale in light of these current standards and conclude by presenting arguments for and against retaining, revis- ing, or rejecting the Hamilton depression scale as the gold standard for assessment of depression.

Method Studies for the review were identified by means of MEDLINE

searches for both “depression” and “Hamilton.” All studies pub- lished during the period since the last major review ( January 1980 to May 2003) were considered. Studies selected for review had to be explicitly designed to evaluate empirically the psychometric properties of the instrument or to review conceptual issues re- lated to the instrument’s development, continued use, and/or shortcomings. At least 20 published versions of the Hamilton de- pression scale exist, including both longer and shortened ver- sions. This review was limited to studies that examined the origi- nal 17-item version, as the majority of the studies that evaluated the scale’s psychometrics used the 17-item version. Only a small number of studies evaluated other versions, and most of these versions contain the original 17 items. Seventy articles met the se- lection criteria and were categorized into three groups on the ba- sis of the major psychometric property examined—reliability, item response, and validity. Table 1 lists the articles included in the review.

Results

Reliability

Clinician-rated instruments should demonstrate three types of reliability: 1) internal reliability, 2) retest reliability, and 3) interrater reliability. Cronbach’s alpha statistic (78) is used to evaluate internal reliability, and estimates ≥0.70

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TABLE 1. Characteristics of Studies Examining the Psychometric Properties of the Hamilton Depression Rating Scalea

% of Female Subjects

Psychometric Properties Examined

Study Year Language N Subjects Reliability Item

Response Validity Aben et al. (8) 2002 Dutch 202 46 Stroke patients × Addington et al. (9) 1990 English 250 —b Schizophrenia inpatients × Addington et al. (10) 1996 English 112c 60 Schizophrenia inpatients × × Addington et al. (10) 1996 English 89d —b Schizophrenia inpatients × × Akdemir et al. (11) 2001 Turkish 94 66 Psychiatric patients × × Baca-García et al. (12) 2001 Spanish 1 100 Dysthymia outpatient × Bech (5) 1981 Danish 66 70 Depressed inpatients × × Bech et al. (13) 1992 Multilingual 1,128 —b Psychiatric patients × × Bech et al. (14) 2002 Danish 650 —b Psychiatric patients × × Berard and Ahmed (15) 1995 English 22 64 Elderly psychiatric outpatients × × Berrios and Bulbena-

Villarasa (16) 1990 Castilian 1,204 59 Psychiatric outpatients × ×

Brown et al. (17) 1995 English 259 —b Medical outpatients × Carroll et al. (18) 1981 English 278 —b Depressed patients × Cicchetti and Prusoff (19) 1983

Time 1 English 86 —b Depressed outpatients × Time 2 English 81 —b Depressed outpatients ×

Craig et al. (20) 1985 English 32 0 Schizophrenia inpatients × × Daradkeh et al. (21) 1997 Arabic 73 58 Depressed inpatients × × Deluty et al. (22) 1986 English 70 39 Psychiatric inpatients × × Demitrack et al. (23) 1998 —b 85 66 Professionals/laypersons × Entsuah et al. (24) 2002

Sample 1 Multilingual 865 65 Psychiatric patients × Sample 2 Multilingual 757 64 Psychiatric patients × Sample 3 Multilingual 450 62 Psychiatric patients ×

Faries et al. (25) 2000 —b 1,658 —b Depressed outpatients × Feinberg et al. (26) 1981 English —b —b Depressed patients × Fleck et al. (27) 1995 French 60 77 Psychiatric outpatients × Fuglum et al. (28) 1996 Danish —b —b Depressed patients × × Gastpar and Gilsdorf (29) 1990 Multilingual 122 66 Depressed patients × Gibbons et al. (30) 1993 English 370 72 Psychiatric patients × × Gilley et al. (31) 1995

Sample 1 English 185 56 Alzheimer’s disease patients × × Sample 2 English 54 39 Comparsion subjects with normal

cognition × ×

Sample 3 English 57 37 Parkinson’s disease patients × × Gottlieb et al. (32) 1988 English 43 67 Neurological patients × × Gullion and Rush (33) 1998 English 324 67 Depressed patients × Hammond (34) 1998 English 100 74 Elderly medical patients × Hooijer et al. (35) 1991 Flemish 56 —b Mental health professionals × Hotopf et al. (36) 1998 English 49 65 Primary care patients × Kobak et al. (37) 1999 English 113 —b Psychiatric patients/community

comparison subjects × ×

Koenig et al. (38) 1995 English 38 55 Elderly medical patients × Lambert et al. (39) 1986 —b 1,850 —b Psychiatric patients × Lambert et al. (40) 1988 English 13 31 Psychiatric inpatients/outpatients × Leentjens et al. (41) 2000 Dutch 63 37 Parkinson’s disease patients × Leung et al. (42) 1999 Chinese 93 56 Psychiatric inpatients × × McAdams et al. (43) 1996 English 101 23 Schizophrenia outpatients × Maier and Philipp (44) 1985 German 280 —b Psychiatric outpatients × Maier et al. (45) 1988

Sample 1 German 130 —b Psychiatric inpatients × × × Sample 2 German 48 —b Psychiatric inpatients × × ×

Maier et al. (46) 1988 German 130 —b Psychiatric inpatients × Marcos and Salamero (47) 1990 Spanish 234 76 Community geriatric subjects × Meyer et al. (48) 2001 English 196 68 Medical outpatients × Middelboe et al. (49) 1994 Danish 36 64 Medical outpatients × Moberg et al. (50) 2001 English 20 70 Geriatric consultation/liaison patients × Mottram et al. (51) 2000 English 433 73 Elderly psychiatric referrals × Naarding et al. (52) 2002

Sample 1 Dutch 44 36 Stroke inpatients × Sample 2 Dutch 274 60 Alzheimer’s disease patients × Sample 3 Dutch 85 40 Parkinson’s disease patients ×

O’Brien and Glaudin (53) 1988 Sample 1 English 183 70 Psychiatric outpatients × Sample 2 English 182 70 Psychiatric outpatients ×

(continued)

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reflect adequate reliability (79, 80). The internal reliability of individual items is calculated by using corrected item- to-total correlation with Pearson’s r; items should have a correlation greater than 0.20 (79, 80). Retest reliability as- sesses the extent to which multiple administrations of the scale generate the same results. When scores on an instru- ment are expected to change in response to effective treat- ment, it is necessary to demonstrate that these scores re- main the same in the absence of treatment. Interrater reliability assesses the extent to which multiple raters gen- erate the same result. Although Pearson’s r is often used to compute these estimates, the preferred method is the intraclass r (81), which allows for adjustment for agree- ment by chance. Estimates of retest and interrater reliabil- ity should be at a minimum of 0.70 (Pearson’s r) and 0.60 (intraclass r) (82). For retest reliability of scale items, Pear- son’s r >0.70 is considered acceptable (83).

Internal Reliability Table 2 summarizes the results from studies examining

internal reliability of the total Hamilton depression scale. Es- timates ranged from 0.46 to 0.97, and 10 studies reported es- timates ≥0.70. Table 3 summarizes the studies that exam- ined internal reliability at the item level. The majority of Hamilton depression scale items show adequate reliability. Six items met the reliability criteria in every sample (guilt, middle insomnia, psychic anxiety, somatic anxiety, gastro- intestinal, general somatic), and an additional five items met the criteria in all but one sample (depressed mood, suicide, early insomnia, late insomnia, work and interests, hypo- chondriasis). Loss of insight was the item with the most vari- able findings, suggesting a potential problem with this item.

Interrater Reliability Total Hamilton depression scale interrater reliabilities

are displayed in Table 2. Pearson’s r ranged from 0.82 to

TABLE 1. Characteristics of Studies Examining the Psychometric Properties of the Hamilton Depression Rating Scalea (continued)

% of Female Subjects

Psychometric Properties Examined

Study Year Language N Subjects Reliability Item

Response Validity O’Hara and Rehm (54) 1983 English 20 0 Depressed outpatients × Olsen et al. (55) 2003 Danish 91 74 Psychiatric and medical patients × Onega and Abraham (56) 1997 English 206 70 Geriatric psychiatric outpatients × Pancheri et al. (57) 2002 Italian 186 62 Depressed outpatients × × Paykel (58) 1990 Sample 1 English 101 —b Depressed inpatients × × Sample 2 English 118 —b Psychiatric outpatients × × Sample 3 English 167 —b General practice outpatients × × Potts et al. (59) 1990 English 694 74 Depressed outpatients × Ramos-Brieva and

Cordero-Villafafila (60) 1988 Spanish 135 70 Depressed inpatients/outpatients × ×

Rehm and O’Hara (61) 1985 English 158 100 Community (symptomatic) subjects × × Reynolds and Kobak (62) 1995 English 357 59 Psychiatric outpatient/nonreferred

community subjects ×

Riskind et al. (63) 1987 English 191 54 Psychiatric outpatients × × Santor and Coyne (64) 2001 Sample 1 English 316 —b Primary care outpatients × Sample 2 English 318 70 Depressed outpatients × Santor and Coyne (65) Sayer et al. (66)

2001 English 732 —b Depressed patients × 1993 English 114 61 Psychiatric inpatients × ×

Senra Rivera et al. (67) 2000 Castilian 52 65 Depressed patients × × Shain et al. (68) 1990 English 45 64 Depressed adolescent inpatients × Smouse et al. (69) 1981 English —b —b Depressed patients × Steinmeyer and Möller (70) 1992 German 223e 68 Psychiatric inpatients × Steinmeyer and Möller (70) 1992 German 174f 68 Psychiatric inpatients × Strik et al. (71) 2001 Sample 1 Dutch 156 0 Medical patients × × Sample 2 Dutch 50 100 Medical patients × × Teri and Wagner (72) 1991 English 75 68 Alzheimer’s patients × Thase et al. (73) 1983 English 147 100 Depressed outpatients × × Thompson et al. (74) 1998 English 242 100 Psychiatric referrals × Whisman et al. (75) 1989 English 70 100 Depressed outpatients × × Williams (76) 1988 English 23 65 Psychiatric inpatients × Zheng et al. (77) 1988 Chinese 329 47 Psychiatric inpatients/outpatients × × a Studies were published between January 1980 and May 2003 and identified by means of a MEDLINE search for both “depression” and

“Hamilton.” b Not reported. c Number of subjects providing data at time 1. d Number of subjects providing follow-up data 3 months after admission. e Number of subjects providing baseline (i.e., pretreatment) data. f Number of subjects providing endpoint (week 6) data after treatment with either paroxetine or amitriptyline.

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0.98, and the intraclass r ranged from 0.46 to 0.99. Some investigators provided evidence that the skill level or ex- pertise of the interviewer and the provision of structured queries and scoring guidelines affect reliability (19, 23, 35, 54). Across studies, the best estimate mean of interrater re- liability for studies reporting higher levels of interviewer skill and use of expert raters, structured queries, and scor- ing guidelines did not statistically differ from that for other studies (z=0.81, n.s.).

At the individual item level, interrater reliability is poor for many items. Cicchetti and Prusoff (19) assessed reli- ability before treatment initiation and 16 weeks later at trial end. Only early insomnia was adequately reliable be- fore treatment, and only depressed mood was adequately reliable after treatment. Thirteen items had coefficients <0.50 before treatment, and 11 items had coefficients <0.50 after treatment. Rehm and O’Hara (61) performed a similar analysis with data from two samples. Six items

showed adequate reliability in the first sample (early in- somnia, middle insomnia, late insomnia, somatic anxiety, gastrointestinal, loss of libido), as did 10 in the second sample (depressed mood, guilt, suicide, early insomnia, middle insomnia, late insomnia, work/interests, psychic anxiety, somatic anxiety, gastrointestinal). Loss of insight showed the lowest interrater agreement in both samples. Craig et al. (20) found that only one item, work/interests, had adequate interrater reliability. Moberg et al. (50) re- ported that nine items demonstrated adequate reliability when the standard Hamilton depression scale was admin- istered (depressed mood, guilt, suicide, early insomnia, late insomnia, agitation, psychic anxiety, hypochondria- sis, loss of insight), but all items showed adequate reliabil- ity when the scale was administered with interview guide- lines. Potts et al. (59) demonstrated that a single omnibus coefficient can mask specific problems. Using a structured interview version of the Hamilton depression scale, they

TABLE 2. Studies Reporting Reliability Estimates for the Total 17-Item Hamilton Depression Rating Scalea

Study Year Internal Reliability (Cronbach’s alpha)

Interrater Reliability (Pearson’s r)

Interrater Reliability (Intraclass r)

Retest Reliability (Pearson’s r)

Addington et al. (9) 1990 0.82 Addington et al. (10) 1996 0.93 Akdemir et al. (11) 2001 0.75 0.87–0.98b 0.85 Baca-García et al. (12) 2001 0.97 Cicchetti and Prusoff (19) 1983

Time 1 0.46 Time 2 0.82

Craig et al. (20) 1985 0.95 Deluty et al. (22) 1986 0.96 Demitrack et al. (23) 1998 0.65–0.79b Fuglum et al. (28) 1996 0.86 0.81 Gastpar and Gilsdorf (29) 1990 0.48 Gilley et al. sample 1 (31) 1995 0.92 Gottlieb et al. (32) 1988 0.99 Hammond (34) 1998 0.46 Kobak et al. (37) 1999 0.91 0.98 Koenig et al. (38) 1995 0.97 Leung et al. (42) 1999 0.94 Maier et al. (45) 1988

Sample 1 0.70 Sample 2

Time 1 0.72 Time 2 0.70

McAdams et al. (43) 1996 0.77 Meyer et al. (48) 2001 0.57–0.80b Middelboe et al. (49) 1994 0.75 O’Hara and Rehm (54) 1983

Expert raters 0.91 Novice raters 0.76

Pancheri et al. (57) 2002 0.90 Potts et al. (59) 1990 0.82 0.92 Ramos-Brieva and Cordero-Villafafila (60) 1988 0.72 Rehm and O’Hara (61) 1985

Study 1 0.76 0.78–0.91b Study 2 0.91–0.96b

Reynolds and Kobak (62) 1995 0.92 0.96 Riskind et al. (63) 1987 0.73 Shain et al. (68) 1990 0.97 Teri and Wagner (72) 1991 0.65–0.97b Whisman et al. (75) 1989 0.85 Williams (76) 1988 0.81 Zheng et al. (77) 1988 0.71 0.92 a Estimates are from studies published between January 1980 and May 2003 that measured psychometric properties of the Hamilton

depression scale. Studies were identified by means of a MEDLINE search for both “depression” and “Hamilton.” b Range over multiple pairs of raters.

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found an overall intraclass coefficient of 0.92; however, two trained psychiatrists differed at least 20% of the time in their ratings of psychic anxiety, psychomotor agitation, and psychomotor retardation, and they differed by at least two points 15% of the time in their ratings of loss of libido. The ratings of trained raters disagreed with the psychia- trists’ ratings on psychomotor agitation (50% of the time), hypochondriasis (60%), loss of libido (90%), and loss of energy (100%).

Retest Reliability

Retest reliability for the Hamilton depression scale ranged from 0.81 to 0.98 (Table 2). Retest reliability at the item level (Table 3) ranged from 0.00 to 0.85. Williams (76) argued in favor of using structured interview guides to boost item and total scale reliability and developed the Structured Interview Guide for the Hamilton Depression Rating Scale. This effort increased the mean retest reliabil- ity across individual items to 0.54, although only four items met the criteria for adequate reliability (depressed mood, early insomnia, psychic anxiety, and loss of libido).

Item Characteristics

Content and scaling. Standard psychometric practice dictates that items within an instrument should measure a single symptom and contain response options linked to increasing or decreasing amounts of that symptom. Each item is assumed to contribute equally to the total score or be backed with evidence in support of differential weight- ing. These criteria are not consistently met by using the current scaling procedure or the options for rating symp- toms. Although improperly scaled items can cause prob- lems in quantitative measurement, evaluation of item scaling takes place first at a qualitative level. Some Hamil- ton depression scale items measure single symptoms along a meaningful continuum of severity; many do not. The item assessing depressed mood includes a combina- tion of affective, behavioral, and cognitive features, such as gloomy attitude, pessimism about the future, subjective feeling of sadness, and tendency to weep. The general so- matic symptoms item, which is also symptomatically het- erogeneous, includes feelings of heaviness, diffuse back- ache, and loss of energy. Headache is coded only as part of somatic anxiety along with such symptoms as indigestion, palpitations, and respiratory difficulties. Genital symp- toms for women entail loss of libido and menstrual distur- bances. The problems inherent in the heterogeneity of these rating descriptors reduce the potential meaningful- ness of these items, a problem exacerbated if the different components of an item actually measure multiple con- structs and thus measure different effects.

Most items on the Hamilton depression scale at least are scaled so that increasing scores represent increasing se- verity. It is less clear whether the anchors used for different scores on certain items actually assess the same underly- ing construct/syndrome. This ambiguity is most obvious

for severity ratings involving psychotic features. The feel- ings of guilt item, for example, is graded as follows: 0=ab- sent, 1=self-reproach, 2=ideas of guilt or rumination over past errors or sinful deeds, 3=present illness is a punish- ment, and 4=hears accusatory or denunciatory voices and/or experiences threatening visual hallucinations. A patient with guilt-themed hallucinations may be more se- verely ill than a patient who has nonpsychotic guilty feel- ings, but is he/she feeling more guilt? The psychotic fea- tures may instead represent a qualitatively different construct/syndrome associated with more severe illness. Similarly, the hypochondriasis item progresses through bodily self-absorption (rated 1) and preoccupation with health (rated 2) before switching to querulous attitude (rated 3) and then again to hypochondriacal delusions (rated 4). These item-scoring anchors violate basic mea- surement principles, because nominal scaling and ordinal scaling are combined in a single item.

Although Hamilton (1) explained the rationale for the inclusion of both 3-point and 5-point items, the argument was not made on the grounds of differential weighting. Hamilton believed that certain items would be difficult to anchor dimensionally and therefore assigned them fewer response options. The end result is that certain items con- tribute more to the total score than others. Contrasting psychomotor retardation and psychomotor agitation, for example, reveals that a severe manifestation of the former contributes 4 points, whereas an equally severe manifes- tation of the latter contributes 2 points. Similarly, some- one who weeps all the time can contribute 3 or 4 points on depressed mood, whereas someone who feels tired all the time can contribute only 2 points on the general somatic symptoms item.

Item Response Analysis

A psychiatric rating scale should measure a single psy- chopathological construct (i.e., an illness or syndrome) and be composed of items that adequately cover a range of symptoms that are consistently associated with the syn- drome. Item response theory, a method used increasingly in the evaluation and construction of psychometric in- struments, permits empirical evaluation of these pre- mises. It is important to note that this method was not available when the original Hamilton depression scale was developed, although some researchers more recently used this method to evaluate this instrument. According to item response theory, a scale and its constituent items may have good reliability estimates but still fail to meet item re- sponse theory criteria. For example, if a depression scale were composed only of items measuring mild depression, the instrument would have great difficulty distinguishing between moderate and severe cases of depression, as both would be characterized by high scores on all items. This is- sue is particularly pressing in studies of clinical change; not only is a wide range of severity often represented in this research, but individual patients are expected to move

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along this continuum as they improve. Continued use of items insensitive to change underestimates the strength of actual treatment effects and makes it necessary to have larger samples to demonstrate that an effect is statistically significant. Falsely identifying patients as not having changed represents an additional source of “noise” and weakens the “signal” of a true treatment effect. A prag- matic implication of such lack of sensitivity is that new compounds shown to be promising in the laboratory may appear spuriously ineffective in clinical trials.

A related issue concerns the extent to which a severity score actually measures a single unidimensional syn- drome. To summarize a syndrome with a single score re- quires a precise understanding of what that score repre- sents. The implicit assumption is that the severity score represents a single dimension (84); if depression is hetero- geneous, interpretation of a single summed score is un- clear. If, for example, items assessing psychological and physical symptoms were only loosely related, a single score would not distinguish between two potentially dif- ferent groups of depressed patients—one group whose symptoms were primarily psychological and another group with primarily vegetative symptoms. Any effects of

an intervention targeting only one of these aspects would be harder to detect.

Gibbons et al. (85) presented a strategy for identifying a unidimensional set of items from a psychiatric rating scale and evaluating the extent to which these items adequately measure the full range of depression severity. Subse- quently, a subset of Hamilton depression scale items that would measure a single dimension of depression across a wide range of severity was developed (30). This subset in- cluded depressed mood, which was sensitive at low levels; work/interests, psychic anxiety, and loss of libido, which were sensitive at mild levels; somatic anxiety, psychomo- tor agitation, and guilt, which were sensitive at moderate levels; and suicide, which was sensitive at severe levels. These items were proposed as a psychometrically stronger form of the full Hamilton depression scale.

Santor and Coyne (64, 65) used item response theory to examine the functioning of the full Hamilton depression scale and its individual items. In one of these studies (65) they examined individual Hamilton depression scale item performance in a combined sample of primary care pa- tients and depressed patients from the National Institute of Mental Health Treatment of Depression Collaborative Research Program. One expects different item ratings at

TABLE 3. Studies Reporting Item Reliability Estimates for the 17-Item Hamilton Depression Rating Scalea

Scale Item

Reliability Measure and Study Year Depressed

Mood Guilt Suicide Early

Insomnia Middle

Insomnia Late

Insomnia Work/

Interests Internal reliabilityb

Berrios and Bulbena-Villarasa (16) 1990 Sample 1 0.32 0.24 0.26 0.25 0.32 0.31 0.39 Sample 2 0.37 0.38 0.40 0.23 0.37 0.42 0.33

Gastpar and Gilsdorf (29) 1990 Time 1 0.10 0.22 –0.04 0.04 0.22 0.13 0.09 Time 2 0.65 0.39 0.50 0.44 0.46 0.53 0.73

Paykel (58) 1990 Sample 1 0.52 0.31 0.31 0.24 0.21 0.38 0.59 Sample 2 0.42 0.38 0.47 0.27 0.34 0.30 0.58 Sample 3 0.52 0.41 0.49 0.34 0.35 0.34 0.59

Rehm and O’Hara (61) 1985 0.63 0.26 0.47 0.40 0.41 0.37 0.46 Interrater reliabilityc

Cicchetti and Prusoff (19) 1983 Time 1 0.37 0.18 0.59 0.76 0.57 0.42 0.33 Time 2 0.72 0.37 0.64 0.57 0.45 0.49 0.64

Moberg et al. (50)d 2001 Standard administration 0.90 0.80 0.90 0.61 0.39 0.89 0.50 Interview guidelines 0.96 0.83 0.81 0.97 0.78 0.89 0.87

Rehm and O’Hara (61)e 1985 Above median split 0.61 0.39 0.49 0.74 0.79 0.72 0.56 Below median split 0.84 0.82 0.92 0.91 0.79 0.92 0.73

Retest reliabilityf Akdemir et al. (11) 2001 0.61 0.78 0.67 0.69 0.79 0.76 0.73 Williams (76) 1988 0.80 0.63 0.64 0.80 0.62 0.30 0.54

a Estimates are from studies published between January 1980 and May 2003 that measured psychometric properties of the Hamilton depres- sion scale. Studies were identified by means of a MEDLINE search for both “depression” and “Hamilton.”

b Correlation of item scores with total scores. An uncorrected Pearson’s r>0.20 was considered significant. Significant correlations are shown in boldface type.

c Interrater Pearson’s r≥0.70 was considered significant; intraclass r≥0.60 was considered significant. Significant correlations are shown in bold- face type.

d The study included both standard and interview guideline methods; interrater reliability was calculated by using the intraclass r. e The subjects were assigned to two groups by means of a median split according to Hamilton depression scale total scores; interrater Pear-

son’s r values were calculated for both groups. f Test-retest Pearson’s r >0.70 was considered acceptable. Acceptable correlations are shown in boldface type.

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different levels of depression severity, with zeroes more common at mild levels of overall depression and higher item scores more common with more severe overall de- pression. Moreover, whereas most items on the Hamilton depression scale are, overall, sensitive to depression sever- ity, 12 items had at least one problematic response option (the five items that had no such problems were depressed mood, guilt, suicide, work/interests, and psychic anxiety) (64). For example, the likelihood of receiving a rating of 1 on the insomnia items was essentially the same regardless of the overall severity of depression, but the likelihood of receiving a rating of 4 on somatic anxiety was very low even when overall depression was severe. These findings confirm that the rating scheme is not ideal for many items on the Hamilton depression scale, with the unfortunate effect of decreasing the capacity of the Hamilton depres- sion scale to detect change (6, 7).

Rasch Analysis

Additional efforts to analyze the performance of indi- vidual Hamilton depression scale items and to identify an underlying single dimension of depression severity have benefited from a technique known as Rasch analysis, a method similar to item response theory. Rasch analysis

proposes an ideal underlying dimension based on mathe- matical and theoretical reasoning about the construct that is being measured and then assesses the extent to which actual data correspond to this ideal. This approach was first applied to the Hamilton depression scale by Bech et al. (86), who confirmed that six items previously shown to have properties associated with unidimensionality (87) could be combined to create a shorter scale that met the formal Rasch criteria. This six-item scale was thus pro- posed as a better measure than the full Hamilton depres- sion scale for assessing depression severity along a single dimension; the six-item scale is composed of items for de- pressed mood, guilt, work/interests, psychomotor retar- dation, anxiety psychic, and general somatic symptoms (87). The unidimensionality of this six-item subscale has since been confirmed in two studies that used Rasch methods (13, 14). Maier and Philipp (44) used Rasch anal- ysis to confirm unidimensionality for a subset of Hamilton depression scale items. The resulting scale was similar to that obtained by Bech et al. (86). In another study that used Rasch analysis (46), six items were found to be prob- lematic: suicide, psychomotor agitation, anxiety somatic, general somatic symptoms, hypochondriasis, and loss of insight.

Scale Item

Retardation Agitation Psychic Anxiety

Somatic Anxiety Gastrointestinal

General Somatic

Loss of Libido Hypochondriasis

Weight Loss

Loss of Insight Mean

0.24 0.24 0.42 0.35 0.33 0.29 0.29 0.34 0.29 0.06 0.29 0.31 0.35 0.36 0.29 0.37 0.34 0.30 0.36 0.26 0.06 0.32

0.03 0.07 0.39 0.34 0.28 0.32 0.05 0.34 –0.04 0.25 0.16 0.40 0.40 0.64 0.58 0.53 0.55 0.55 0.23 0.11 0.27 0.47

0.33 0.37 0.53 0.41 0.52 0.25 0.27 0.33 0.40 0.45 0.38 0.33 0.20 0.33 0.47 0.63 0.50 0.39 0.43 0.49 0.23 0.40 0.21 0.25 0.50 0.42 0.41 0.44 0.23 0.16 0.42 –0.07 0.35 0.14 0.18 0.54 0.46 0.27 0.38 0.13 0.33 0.25 0.16 0.34

0.39 0.20 0.19 0.34 0.43 0.30 0.39 0.29 0.57 –0.02 0.37 0.26 0.32 0.40 0.45 0.51 0.42 0.59 –0.04 0.06 –0.03 0.40

0.46 0.89 0.67 0.57 0.34 0.57 0.39 0.76 0.58 0.63 0.64 0.75 0.97 0.88 0.84 0.95 0.92 0.94 0.89 1.00 1.00 0.90

0.54 0.51 0.52 0.88 0.75 0.55 0.77 0.35 0.51 0.37 0.59 0.69 0.52 0.71 0.82 0.73 0.68 0.69 0.64 0.54 0.22 0.72

0.85 0.66 0.80 0.79 0.71 0.66 0.76 0.79 0.08 0.79 0.70 0.32 0.11 0.78 0.66 0.59 0.61 0.70 0.55 0.58 0.00 0.54

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Validity

Validity of psychiatric rating scales such as the Hamil- ton depression scale comprises 1) content, 2) convergent, 3) discriminant, 4) factorial, and 5) predictive validity. Content validity is assessed by examining scale items to determine correspondence with known features of a syn- drome. Convergent validity is adequate when a scale shows Pearson’s r values of at least 0.50 in correlations with other measures of the same syndrome. Discriminant validity is established by showing that groups differing in their diagnostic status can be separated by using the scale. Predictive validity for symptom severity measures such as the Hamilton depression scale is determined by a statisti- cally significant (p<0.05) capacity to predict change with treatment. Factorial validity is established by using factor analysis or related techniques (e.g., principal-component analysis) to demonstrate that a meaningful structure can be found in multiple samples. An a priori criterion of 0.40 has been used to identify which items are part of which factors (88).

Content validity. Because of its wide use and long clini- cal tradition, the Hamilton depression scale seems to both define as well as measure depression. One could criticize DSM-IV for not adequately capturing Hamilton depres- sion scale depression as much as one could criticize the Hamilton depression scale for not providing full coverage of DSM-IV depression. Nonetheless, the operational crite- ria provided in DSM-IV are used as the official nosology for much of psychiatry worldwide. The criteria for major

depression have been revised three times in response to developments in field trial research and clinical consensus based on expert opinion, most recently in 1994. Research- ers have developed a number of longer versions of the Hamilton depression scale that include additional symp- toms such as the reverse vegetative features of atypical de- pression. However, the core items of the Hamilton depres- sion scale have remained unchanged for more than 40 years. It is reasonable to ask whether this instrument cap- tures depression as it is currently conceptualized. Several symptoms contained within the Hamilton depression scale are not official DSM diagnostic criteria, although they are recognized as features associated with depression (e.g., psychic anxiety). For other symptoms included in the Hamilton depression scale (e.g., loss of insight, hypochon- driasis), the link with depression is more tenuous. More critically, important features of DSM-IV depression are of- ten buried within more complex items and sometimes are not captured at all. The work/interests item includes an- hedonic features along with listlessness, indecisiveness, social avoidance, and lowered productivity. It is impossi- ble to determine the extent to which anhedonia per se in- fluences severity. Guilt is captured in both Hamilton de- pression scale depression and DSM-IV depression, but the Hamilton depression scale contains no explicit assess- ment of feelings of worthlessness. Decision-making diffi- culties are buried within the work/interests item of the Hamilton depression scale, but concentration difficulties are not included. The reverse vegetative symptoms—

TABLE 4. Studies Reporting Estimates of Convergent Validity of the 17-Item Hamilton Depression Rating Scale, Compared With Other Depression Measuresa

r

Study Year

Beck Depression Inventory

Brief Psychiatric

Rating Scale

Center for Epidemiologic

Studies Depression Scale

Clinical Global Impression

Scale

Carroll Rating Scale

for Depression

Global Assessment

Scale Akdemir et al. (11) 2001 0.48 0.56 Berard and Ahmed (15) 1995 0.48 Brown et al. (17) 1995 0.70–0.85b Carroll et al. (18) 1981 0.60 0.71 Craig et al. (20) 1985 0.56 0.65 Feinberg et al. (26) 1981 0.77 0.75 Gottlieb et al. (32) 1988

Low-severity group 0.89 High-severity group 0.57

Hotopf et al. (36) 1998 0.77 Kobak et al. (37) 1999 0.89 Leung et al. (42) 1999 Maier et al. total sample (46) 1988 Olsen et al. (55) 2003 Rehm and O’Hara (61) 1985 0.73 –0.86 Senra Rivera et al. (67) 2000

Time 1 0.70 Time 2 0.92

Whisman et al. (75) 1989 Time 1 0.27 0.41 Time 2 0.67 0.68

Zheng et al. (77) 1988 –0.47 a Estimates are from studies published between January 1980 and May 2003 that measured psychometric properties of the Hamilton depres-

sion scale. Studies were identified by means of a MEDLINE search for both “depression” and “Hamilton.” b Multiple assessments over an 8-month period.

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weight gain, hyperphagia, and hypersomnia—were pro- vided by Hamilton (1) as additional items but are not scored on the original Hamilton depression scale.

Convergent validity. A wide range of instruments has been used to examine the convergent validity of the Hamil- ton depression scale (Table 4). Most of the correlation co- efficients met the preestablished criterion, and the Hamil- ton depression scale showed adequate convergent validity in correlations with all but two scales, including the major depression section of the Structured Clinical Interview for DSM-IV. The latter finding provides evidence of noncorre-

spondence between the Hamilton depression scale and DSM-IV.

Discriminant validity. Two approaches have been used to evaluate the discriminant validity of the Hamilton de- pression scale. In the first approach, several studies used the receiver operating curve as a statistical means of deter- mining the cutoff scores for detecting depression and then provided corresponding rates of sensitivity, specificity, positive predictive power, and negative predictive power for the Hamilton depression scale in distinguishing de- pressed and nondepressed subjects. In other studies, re-

r

Hospital Anxiety and Depression

Scale

Montgomery- Åsberg

Depression Rating Scale

Major Depression Inventory

Minnesota Multiphasic Personality Inventory

Raskin Depression

Scale

Structured Clincial

Interview for DSM-IV

Visual Analogue

Scale

Zung Self-Rating Depression

Scale 0.37

0.38

–0.65

0.49 0.01

0.67 0.85 0.65

0.86 0.67 0.81

0.68 0.88

0.20 0.50 0.62

TABLE 5. Studies Reporting Classification Accuracy Rates for the 17-Item Hamilton Depression Rating Scalea

Study Year Cutoff Scoreb Sensitivity Specificity Positive

Predictive Value Negative

Predictive Value Aben et al. (8) 2002 12 0.78 0.75 0.37 0.95 Leentjens et al. (41) 2000 13/14 0.88 0.86 0.84 0.89 Leung et al. (42) 1999 12/13 0.88 0.86 0.84 0.89 Mottram et al. (51) 2000 15/16 0.88 0.99 0.99 0.97 Naarding et al. (52) 2002

Sample 1 10/11 0.73 1.00 1.00 0.88 Sample 2 13/14 0.45 0.96 0.76 0.86 Sample 3 15/16 0.70 0.99 0.93 0.91

Strik et al. (71) 2001 11/12 0.76 0.86 0.41 0.99 Thompson et al. (74) 1998 —c 0.69–0.87d 0.99–1.00d —c —c Mean 12.6/13.5 0.76 0.91 0.77 0.92 a Rates are from studies published between January 1980 and May 2003 that measured psychometric properties of the Hamilton depression

scale. Studies were identified by means of a MEDLINE search for both “depression” and “Hamilton.” b The minimum score above which sensitivity and specificity are maximized in the detection of depression with the Hamilton depression scale

for a given study. Where two scores are given, the lower score represents the threshold below which cases are classified as nondepressed, and the higher score represents the threshold above which cases are classified as depressed.

c Not reported. d Range of scores across multiple assessments.

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searchers have examined the capacity of the Hamilton de- pression scale to distinguish different groups of clinical patients (e.g., patients with endogenous versus those with nonendogenous depression, patients with anxiety versus those with depression) using statistical techniques to de- tect mean group differences. Classification rates resulting from receiver operating curve analysis have not been widely reported in the Hamilton depression scale litera- ture. Our search only identified seven studies (Table 5), and some of these investigations sought to detect depression in samples of patients with medical conditions other than psychiatric disorders (Table 1). Sensitivity, specificity, and negative predictive power were generally consistent and large, but positive predictive power was more variable, and two studies reported very low positive predictive power.

The second type of discriminant validity study attempts to distinguish different clinical groups. In a comparison of healthy, depressed, and bipolar depressed individuals, Rehm and O’Hara (61) found that the total Hamilton de- pression scale score clearly differentiated these three cate- gories, with the depressed patients scoring higher than the healthy participants and with the bipolar depressed pa- tients scoring higher than both of the other groups. At the item level, four items—psychomotor agitation, gastro- intestinal symptoms, loss of insight, and weight loss— failed to differentiate depressed from healthy subjects. Only psychic anxiety and hypochondriasis significantly differentiated the subjects with unipolar and bipolar de- pression. Kobak et al. (37) showed significant total scale score differences between individuals with major depres-

sion, individuals with minor depression, and healthy com- parison subjects. Zheng et al. (77) reported that the Hamil- ton depression scale was able to discriminate psychiatric patients classified as mildly, moderately, and severely dys- functional on the basis of Global Severity Scale scores. Thase et al. (73) found that the Hamilton depression scale could distinguish patients with endogenous depression from patients with nonendogenous depression, with pa- tients in the former category having higher scores. Gott- lieb et al. (32) reported no significant differences between the Hamilton depression scale scores of patients classified as having low-severity versus high-severity Alzheimer’s disease. Several researchers have investigated the capacity of the Hamilton depression scale to differentiate between patients with anxiety and those with depression. Prusoff and Klerman (89) suggested the Hamilton depression scale could indeed separate these constructs, and Maier et al. (45) demonstrated that the Hamilton depression scale had a higher correlation with an external measure of de- pression than with an external measure of anxiety, but the saturation of the Hamilton depression scale with anxiety- related concepts was nonetheless considerable.

Predictive validity. Edwards et al. (90) performed a meta- analysis of 19 studies with a total of 1,150 patients that compared the predictive validity of the Hamilton depres- sion scale and the Beck Depression Inventory. Treatments included pharmacotherapy, behavior therapy, cognitive restructuring, dynamic psychotherapy, and various com- binations. The Hamilton depression scale was found to be

TABLE 6. Studies Reporting Factor Analyses and Principal-Component Analyses of the 17-Item Hamilton Depression Rating Scalea

Study Year Number

of Factors Depressed

Mood Guilt Suicide Early

Insomnia Middle

Insomnia Late

Insomnia Work/

Interests Addington et al. (10) 1996

Time 1 7 I I, V V — II II, V, VI I, IV Time 2 7 I, II, VII II, III, VII VII III III III, V II

Akdemir et al. (11) 2001 6 — II II III III III — Berrios and

Bulbena-Villarasa (16) 1990 Sample 1 4 I I, II I I I I II Sample 2 4 I I, II I IV I, IV I I, II, IV

Brown et al. (17) 1995 6 III III III I V V VI Daradkeh et al. (21) 1997 5 II II, IV I I III Fleck et al. (27) 1995 3 I I — III III III I Gibbons et al. (30) 1993 5 I, IV I I — II II I, IV Marcos and Salamero (47) 1990 3 II — II III III III II O’Brien and Glaudin (53) 1988

Sample 1 6 I I, VI I — IV IV I, II Sample 2 8 III VII VI II II II III

Onega and Abraham (56) 1997 4 I I I II II II I Pancheri et al. (57) 2002 4 III II — I I I III Ramos-Brieva and

Cordero-Villafafila (60) 1988 5 III II, III I, III I I I III Smouse et al. (69) 1981 3 I I I, II I, II I, II I, II I Steinmeyer and Möller (70) 1992

Time 1 6 II V V III III III II Time 2 2 I, II II I, II II I I I

Zheng et al. (77) 1988 5 III IV III V V V IV a Results are from studies published between January 1980 and May 2003 that measured psychometric properties of the Hamilton depression

scale. Studies were identified by means of a MEDLINE search for both “depression” and “Hamilton.” Roman numerals indicate the number of the factor on which the item loaded significantly. A factor loading of ≥0.40 was considered statistically significant.

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more sensitive to change, compared to the Beck Depres- sion Inventory. Lambert et al. (39) performed a meta-anal- ysis that included 36 studies and a total of 1,850 patients and that compared the Hamilton depression scale to the Beck Depression Inventory and the Zung Self-Rating De- pression Scale. They reported that the Hamilton depres- sion scale was more sensitive to change than were the two self-report measures. Sayer et al. (66) also demonstrated that the Hamilton depression scale outperformed the Beck Depression Inventory in detecting change. Lambert et al. (40) reported that the Beck Depression Inventory is more likely to show treatment effects at 12 weeks than the Zung Self-Rating Depression Scale or the Hamilton de- pression scale; the Zung Self-Rating Depression Scale and the Hamilton depression scale were more likely to detect changes after 3 weeks.

One disadvantage of a multidimensional instrument such as the Hamilton depression scale in detecting change is that specific treatments may affect only a single dimen- sion. If the total score includes somatic symptoms that ac- tually reflect treatment side effects, estimates of treatment response will be spuriously low (44). In two studies and one meta-analysis researchers addressed this issue using the various unidimensional core depression item sets de- scribed earlier in the section on item characteristics (91, 92). The six-item subscale developed by Bech et al. (87) was found to be at least as responsive as the full Hamilton depression scale. A meta-analysis of eight fluoxetine stud-

ies with 1,658 patients showed that the different uni- dimensional subscales (44, 87) were more sensitive to change than was the full Hamilton depression scale score. These results were replicated in a second meta-analysis of four tricyclic antidepressant studies (25).

Factorial validity. A total of 15 studies with 17 samples reported a factor analysis of the Hamilton depression scale (Table 6). In most of the studies, researchers used the eigenvalue ≥1 rule to determine the number of factors, ex- tracted those factors from the data using principal-com- ponent analysis, and then determined the optimal config- uration of items on factors using varimax rotation. The number of factors identified ranged from two to eight. In- somnia items appeared consistently on the same factor in 13 data sets, suggesting a sleep disturbance factor. There was some support for the presence of a general depression factor, as depressed mood, guilt, and suicide appeared to- gether on the same factor in six data sets, and the combi- nation of depressed mood, suicide, and psychic anxiety appeared on the same factor in seven data sets. Support was also found for an anxiety/agitation factor, with the ag- itation, psychic anxiety, and somatic anxiety items ap- pearing together in six samples. Clearly, the Hamilton de- pression scale is not unidimensional, as separate sets of items do seem to reliably represent general depression and insomnia factors; however, the exact structure of the Hamilton depression scale’s multidimensionality remains unclear.

Retardation Agitation Psychic Anxiety

Somatic Anxiety Gastrointestinal

General Somatic

Loss of Libido Hypochondriasis

Weight Loss

Loss of Insight

IV III, VI VII I VII I, VII IV, VII III I, VI VI II II, III I, II I I VI VI IV I, IV, V I V — I, II II I VI IV IV I VI

II I I I, II I, III I IV I III III II II I, III I, III I I I, IV I I, III III III I I I II VI V IV IV II

I, II I, III V V V II, III II IV I II II II II I — II II — IV I I I V IV — — III, V III II — II I — I I I — —

V V I II III II I II, IV III VI I

I III V, VI IV V VII VI IV VIII I IV III III II I I III II IV — II — I I, IV — – I IV —

III II II II IV IV IV V V II III I, II I, III I I I

IV I II I VI IV VI I IV IV — II I I I I — — — — IV II I I I I III I I II

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Conclusions

The Hamilton depression scale has been the standard for the assessment of depression for more than 40 years. Re- searchers and policy makers charged with the task of pro- viding standards to evaluate treatment outcomes in de- pression are faced with three possible solutions: retain, revise, or reject. The latter solution argues for the develop- ment of a new instrument or the replacement of the Hamil- ton depression scale with existing, psychometrically supe- rior instruments.

Many of the psychometric properties of the Hamilton depression scale are adequate and consistently meet es- tablished criteria. The internal, interrater, and retest reli- ability estimates for the overall Hamilton depression scale are mostly good, as are the internal reliability estimates at the item level. Similarly, established criteria are met for convergent, discriminant, and predictive validity, al- though the latter does suffer somewhat due to multidi- mensionality. At the item level, interrater and retest coeffi- cients are weak for many items, and the internal reliability coefficients indicate that some items are problematic. The lack of individual item reliability is not necessarily a fatal psychometric flaw; what is critical is that the items as a whole provide adequate reliability.

Evaluation of item response shows that many of the individual items are poorly designed and sum to generate a total score whose meaning is multidimensional and un- clear. The problem of multidimensionality was highlighted in the evaluation of factorial validity, which showed a fail- ure to replicate a single unifying structure across studies. Although the unstable factor structure of the Hamilton de- pression scale may be partly attributable to the diagnostic diversity of population samples, well-designed scales as- sessing clearly defined constructs produce factor struc- tures that are invariant across different populations (88). Finally, the Hamilton depression scale is measuring a con- ception of depression that is now several decades old and that is, at best, only partly related to the operationalization of depression in DSM-IV.

These findings indicate that continued use of the Hamil- ton depression scale requires, at the very least, a complete overhaul of its constituent items. Accumulated empirical evidence offers some hope that substantial revision can redress a number of psychometric problems, thereby pro- viding an improved measure. Shortened versions of the Hamilton depression scale converge on a common set of core features and in general have proven more effective in detecting change. The truncated item sets for these instru- ments, however, are limited in that they do not permit capture of the full depressive syndrome. Other studies based on item response theory methods have indicated that modifications of the rating scheme are readily imple- mented and can enhance the unidimensionality of these core symptoms in a manner that allows uniform assess- ment of change. Identifying a core set of symptoms with

proven psychometric qualities, along with making rating scheme changes that would allow consistent assessment of the severity of depression, could provide a foundation for a reconstructed scale. One advantage of such a revision is that it would maintain continuity with the long-stand- ing use of the original Hamilton depression scale. This sort of transition is probably more palatable and therefore more readily acceptable to regulatory commissions.

The Depression Rating Scale Standardization Team re- vised the Hamilton depression scale (i.e., the GRID-HAMD [93, 94]) by employing several of the methodological ad- vances we have been advocating in this article. They used item response theory methods to inform, in part, the re- vision process; developed clear structured interview prompts and scoring guidelines; and to some extent stan- dardized the scoring system. We nonetheless believe that by making an effort to retain the original 17 items, the De- pression Rating Scale Standardization Team failed to ad- dress many of the flaws of the original instrument. Most of the items still measure multiple constructs, items that have consistently been shown to be ineffective have been retained, and the scoring system still includes differential weighting of items. Moreover, the GRID-HAMD content is virtually unchanged from the original. All the items that appeared on the Hamilton depression scale in 1960 are included in the GRID-HAMD. Thus, this revision has neither removed items based on outdated concepts nor added items that incorporate contemporary definitions of depression.

Rejection of the Hamilton depression scale and replace- ment with an alternative existing measure or the imple- mentation of a new instrument has scientifically compel- ling advantages over revision. The Inventory of Depressive Symptomatology (95) and the Montgomery-Åsberg De- pression Rating Scale (96), designed to address the limita- tions of the Hamilton depression scale, represent two potential replacement alternatives. Although these instru- ments measure contemporary definitions of depression (33), neither item response theory methods nor other con- temporary measurement techniques were employed in their development. As indicated earlier, such techniques, especially item response theory, maximize the capacity of an instrument to detect change. On the other hand, the de- velopment and implementation of a new instrument that is based on current knowledge of depression and that takes advantage of psychometric and statistical advances might offer the best solution. The decision to replace the Hamil- ton depression scale with either an existing instrument or a newly developed instrument would ultimately rest on con- sensus that such an instrument could capture more ade- quately the full spectrum of the depression construct and on empirical evidence of the new instrument’s superiority in detecting treatment effects.

In conclusion, we have been struck with the marked contrast between the effort and scientific sophistication involved in designing new antidepressants and the con-

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tinued reliance on antiquated concepts and methods for assessing change in the severity of the depression that these very medications are intended to affect. Effort in both areas is critical to the accessibility of new medica- tions for patients with depression. Many scales and instru- ments used in psychiatry today are based on—or at least include—current DSM symptoms, and the measurement of depression should follow this trend. It is time to retire the Hamilton depression scale. The field needs to move forward and embrace a new gold standard that incorpo- rates modern psychometric methods and contemporary definitions of depression.

Received Dec. 7, 2003; revision received Feb. 26, 2004; accepted March 22, 2004. From the Centre for Addiction and Mental Health, University of Toronto; and the Department of Psychology, University of British Columbia, Vancouver, B.C. Address reprint requests to Dr. Bagby, Centre for Addiction and Mental Health, 250 College St., Tor- onto, Ont., Canada M5T 1R8; [email protected] (e-mail).

Supported in part by Eli Lilly and Co. and by a Senior Research Fel- lowship from the Ontario Mental Health Foundation to Dr. Bagby. Mr. Ryder was supported by a postdoctoral fellowship from the Michael Smith Foundation for Health Research, Vancouver, B.C., Canada.

The authors thank Arun Ravindrun and Sid Kennedy for their com- ments and Natasha Owen for assistance with the manuscript.

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