The Hamilton Rating Scale for Depression (often abbreviated to HRSD, HDRS or Ham-D) was written in the late 1950s by Max Hamilton, a psychiatrist at Leeds University and originally designed to evaluate the performance of the first group of antidepressants . The scale is still widely used to measure the effectiveness of antidepressant medication in clinical trials. For more than 40 years, it was considered to be the ‘gold standard’ but in the 1990s, its use began to be questioned .
The questionnaire is designed to be used by a health care professional during a clinical interview with an already identified depressed patient. Hamilton suggested that no specific questions needed to be asked during an unstructured interview in a health care setting. He indicated that the value of the questionnaire ‘depends entirely on the skill of the interviewer’ . The interview should typ ically take between 15 and 20min and in practice this time taken may well limit its use outside a psychiatric clinical setting.
Scoring and interpretation
The scale is widely available and has two common versions with either 17 or 21 items and is scored between 0 and 4 points. The first 17 items measure the severity of depressive symptoms and as examples the interviewer rates the level of agitation clinically noted during the interview or how the mood is impacting on an individual’s work or leisure pursuits. The extra four items on the extended 21-point scale measure factors that might be related to depression, but are not thought to be measures of severity, such as paranoia or obsessional and compulsive symptoms. Scoring is based on the 17-item scale and scores of 0–7 are considered as being normal, 8–16 suggest mild depression, 17–23 moderate depression and scores over 24 are indicative of severe depression ; the maximum score being 52 on the 17-point scale.
Validity and performance
A major review of 70 studies suggested that the internal, inter-rater and retest reliability estimates are adequate for the global score but are weaker for individual items . It has been suggested in studies that inter-rater reliability is affected by the level of training undertaken by the interviewer  and whether a structured interview guide is provided . In comparison to the Beck Depression Inventory, a meta-analysis suggested that after therapeutic treatments, the HRSD was more ‘sensitive to change’ on retesting  and this is probably why it has been so widely used in clinical trials.
The Hamilton scale has been criticized for burying important features of the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) diagnostic criteria such as feelings of worthlessness and anhedonia . This is likely to be because it is more than 50 years old and designed before the DSM-IV criteria were established.
The Hamilton depression scale is widely available in the public domain and is not protected by copyright.