3/11/25, 9:54 AM Severity classification on the Hamilton depression rating scale - ScienceDirect

Journal of Affective Disorders

Volume 150, Issue 2, 5 September 2013, Pages 384-388

Research report

Severity classification on the Hamilton

depression rating scale
Mark Zimmerman , Jennifer H. Martinez, Diane Young, Iwona Chelminski, Kristy Dalrymple

Department of Psychiatry and Human Behavior, Brown Medical School, Rhode Island
Hospital, 146 West River Street, Providence, RI, United States

Received 31 January 2013, Accepted 19 April 2013, Available online 4 June 2013.

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Abstract

Background
Symptom severity as a moderator of treatment response has been the subject of debate
over the past 20 years. Each of the meta- and mega-analyses examining the treatment
significance of depression severity used the Hamilton Depression Rating Scale (HAMD),
wholly, or in part, to define severity, though the cutoff used to define severe depression
varied. There is limited empirical research establishing cutoff scores for bands of severity
on the HAMD. The goal of the study is to empirically establish cutoff scores on the HAMD
in their allocation of patients to severity groups.

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3/11/25, 9:54 AM Severity classification on the Hamilton depression rating scale - ScienceDirect

Methods
Six hundred twenty-seven outpatients with current major depressive disorder were
evaluated with a semi-structured diagnostic interview. Scores on the 17-item HAMD
were derived from ratings according to the conversion method described by Endicott et
al. (1981). The patients were also rated on the Clinical Global Index of Severity (CGI).
Receiver operating curves were computed to identify the cutoff that optimally
discriminated between patients with mild vs. moderate and moderate vs. severe
depression.

Results
HAMD scores were significantly lower in patients with mild depression than patients
with moderate depression, and patients with moderate depression scored significantly
lower than patients with severe depression. The cutoff score on the HAMD that
maximized the sum of sensitivity and specificity was 17 for the comparison of mild vs.
moderate depression and 24 for the comparison of moderate vs. severe depression.

Limitations
The present study was conducted in a single outpatient practice in which the majority of
patients were white, female, and had health insurance. Although the study was limited
to a single site, a strength of the recruitment procedure was that the sample was not
selected for participation in a treatment study, and exclusion and inclusion criteria did
not reduce the representativeness of the patient groups. The analyses were based on
HAMD scores extracted from ratings on the SADS. However, we used Endicott et al.'s
(1981) empirically established formula for deriving a HAMD score from SADS ratings, and
our results concurred with other small studies of the mean and median HAMD scores in
severity groups.

Conclusions
Based on this large study of psychiatric outpatients with major depressive disorder we
recommend the following severity ranges for the HAMD: no depression (0–7); mild
depression (8–16); moderate depression (17–23); and severe depression (≥24).

Introduction

The importance of severity in selecting and evaluating the efficacy of treatment for
depressed patients has received increased attention recently. The Third Edition of the
American Psychiatric Association's (APA's) guidelines for the treatment of major
depressive disorder recommended both psychotherapy and pharmacotherapy as

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monotherapies for depression of mild and moderate severity, and pharmacotherapy

(with or without psychotherapy) for severe depression (American Psychiatric
Association, 2010). The National Institute for Health and Clinical Excellence (NICE)
updated guidelines for the treatment and management of depression discouraged the
use of antidepressant medication as the initial treatment option for mild depression, and
recommended medication together with empirically supported psychotherapy for
moderate and severe depression (National Collaborating Center for Mental Health, 2009).
As reported by van der Lem et al. (2011), treatment guidelines in the Netherlands also
recommended pharmacotherapy as the first treatment option for severely depressed
patients, and either pharmacotherapy or psychotherapy for mildly and moderately
depressed patients. While the recommendations in these guidelines are not entirely
consistent, they are unanimous in recommending medication as the treatment of choice
for severe depression.

Symptom severity as a moderator of treatment response has been the subject of ongoing
debate since the publication of the results from the National Institute of Mental Health
Treatment of Depression Collaborative Research Program (TDCRP) suggesting that
psychotherapy was not as effective as medication in the acute treatment of severe
depression (Elkin et al., 1995, Elkin et al., 1989). In 1999, DeRubeis et al. (1999) noted that
treatment guidelines from the American Psychiatric Association (1993) and Agency for
Health Care Policy and Research (1993) recommended antidepressant medication, and
not psychotherapy, for severe depression, and these recommendations were largely
based on the findings of the TDCRP. The importance of severity was recently renewed in
another context—the range of effectiveness of antidepressant medication. Kirsch et al.
(2008) conducted a meta-analysis of antidepressant treatment trials in the FDA data base
and found that drug-placebo differences increased as baseline severity increased, and
concluded that antidepressants were only minimally more effective than placebo for
mildly and moderately depressed patients. This conclusion was reinforced by the results
of a mega-analysis of 6 studies by Fournier et al. (2010), though a recent, larger, mega-
analysis found that the efficacy of two antidepressants, fluoxetine and venlafaxine, over
placebo was independent of severity (Gibbons et al., 2012). The severity of depression
has also continued to retain importance in moderating the effect of psychotherapy,
though a recent meta-analysis of psychotherapy studies found that greater symptom
severity did not predict poorer response in controlled studies examining the moderating
effect of severity (Driessen et al., 2010).

Each of these meta- and mega-analyses used the Hamilton Depression Rating Scale
(HAMD) (1960), wholly, or in part, to define severity, though the cutoff used to define
severe depression varied. DeRubeis et al. (1999) conducted a mega-analysis of 4 studies
comparing cognitive-behavioral therapy and medication. Following the precedent of the
TDRCP, DeRubeis et al. defined severe depression as a cutoff of 20 or more on the 17-item
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HAMD. Likewise, the recent mega-analysis of placebo-controlled trials of fluoxetine and

venlafaxine cited the TDRCP in using a cutoff >20 to define severe depression. Of note, no
empirical justification was given in the TDRCP for using this threshold to define severe
depression (Elkin et al., 1989). In fact, Elkin et al.'s (1989) did not refer to the patients
scoring above 20 on the HAMD in absolute terms (i.e., having severe depression), but
instead referred to them in relative terms (i.e., having more severe depression than the
patients scoring 20 and below). In Kirsch et al. (2008) meta-analysis the authors noted
that the mean baseline HAMD scores of the antidepressant efficacy trials were in the
very severe range (i.e., ≥23 based on the APA's Handbook of Psychiatric Measures (Rush
et al., 2008) for all but 2 of the 35 studies included in the analysis. Prior to the report by
Kirsch and colleagues, Khan et al. (2002) examined the FDA data base, and also found
that drug-placebo differences increased with increasing mean baseline HAMD scores.
Khan et al. (2002) divided the studies into 3 groups based on pretreatment HAMD scores
(≤24, 25–27, ≥28) without indicating the basis for using these cutoff scores to define the
groups. Fournier et al. (2010) used the thresholds recommended in the APA's Handbook
of Psychiatric Measures (Rush et al., 2008) to define grades of severity on the HAMD
(mild to moderate≤18; severe 19 to 22; very severe ≥23).

In contrast to all of these studies, and the APA guidelines, most pharmacotherapy studies
have used a cutoff of 25 on the 17-item HAMD to define severe depression (Dunner et al.,
2005, Kasper, 1997, Montgomery et al., 2003, Schmitt et al., 2009, Shelton et al., 2007,
Versiani et al., 2005), and this cutoff has been recommended by several experts to define
severe depression (Hirschfeld, 1999, Montgomery and Lecrubier, 1999, Schatzberg, 1999).

Fundamental to all of these studies on the treatment implications of severity is the

validity of the cutoffs on the HAMD to define the severity categories. In none of the
discussion sections of these reports were questions raised about the cutoffs used to
define the grades of severity. The APA's Handbook of Psychiatric Rating Scales (Rush et
al., 2008) cited two studies in support of the cutoff scores to identify severity subtypes.
One was a study examining the validity of deriving a HAMD equivalent score on the
Schedule for Affective Disorders and Schizophrenia (Endicott et al., 1981). In fact, this
study did not attempt to determine the cutoff scores on the HAMD indicating grades of
severity. Rather, when examining the agreement between the extracted and original
HAMD in classifying patients into severity categories, the authors used a cutoff of 25 to
indicate severe depression (and a cutoff of 18 to distinguish mild and moderate
depression). The second study cited as evidence for using a cutoff of 23 to indicate severe
depression examined the association between HAMD scores and global ratings of
severity in 59 depressed inpatients (Kearns et al., 1982). The authors did not derive (or
recommend) cutoff scores corresponding to severity levels. In Figure 2 of their paper, the
authors graphed the mean HAMD for patients rated at different levels of severity. Visual
inspection of this figure suggests that very severe depression corresponded to a mean
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HAMD score of approximately 29 and severe depression corresponded to a mean HAMD

score of 21. If these groups were combined, the mean HAMD for the severe category
would be approximately 25. Thus, it is unclear why a cutoff of 19 was recommended in
the APA Handbook to identify severe depression. We are aware of only 2 other small
studies comparing HAMD scores to clinical global severity ratings. Knesevich et al. (1977)
evaluated a sample of 26 outpatients, 9 of whom were rated in the severe range. Visual
inspection of the figure plotting the distribution of scores suggests that the median score
for these patients was 24. Muller et al. (2003) evaluated 85 depressed inpatients, 26 of
whom were rated severe. The results of a receiver operating curve analysis to determine
the optimal cutoff score on the HAMD to indicate severe depression found that a cutoff
of 25 provided the best balance of sensitivity and specificity.

There is thus a limited amount empirical research establishing cutoff scores for bands of
severity on the HAMD. Because of the significance accorded severity by treatment
guidelines it is important to empirically establish cutoff scores on the HAMD in the
allocation of patients to severity groups. Accordingly, in the present report from the
Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project
we compared HAMD scores to clinician global ratings of severity in a large sample of
depressed outpatients.

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Section snippets

Methods

The Rhode Island MIDAS project represents an integration of research methodology into
a community-based outpatient practice affiliated with an academic medical center
(Zimmerman, 2003). A comprehensive diagnostic evaluation is conducted upon
presentation for treatment. This private practice group predominantly treats individuals
with medical insurance (including Medicare but not Medicaid) on a fee-for-service basis,
and it is distinct from the hospital's outpatient residency training clinic …

Results

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The mean score on the CGI was 3.1 (SD=.5) corresponding to a moderate level of severity.
A small number of patients were rated extremely depressed (.8%, n=5), and these
patients were included in the severe group. The majority of the patients were rated as
having moderate depression (73.5%, n=461). More patients were rated as having severe
depression (18.5%, n=116) than mild depression (7.5%, n=47). Two patients were rated as
having minimal depression during the week prior to the evaluation and …

Discussion

Treatment guidelines for depression suggest that it is important to consider severity

when selecting a patient's initial treatment modality (American Psychiatric Association,
2010, et al.,, van der Lem et al., 2011). That is, for severely depressed patients the
guidelines indicate that pharmacotherapy is the treatment of choice, whereas for mildly
and moderately depressed patients both pharmacotherapy and psychotherapy are
recommended options. While the moderating effect of severity on the …

Role of funding source

None. …

Conflict of interest

None. …

Acknowledgments
None. …

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