Hamilton Anxiety Rating Scale HAM-A
Hamilton Anxiety Rating Scale HAM-A overview
Creator and Context
The Hamilton Anxiety Rating Scale (HAM-A) is a 14 item clinician rated measure of anxiety severity, published by Max Hamilton in 1959.
It is one of the oldest anxiety measures still in routine use and remains a standard outcome measure in anxiety trials. It is in the public domain.
Presenting Conditions
The 14 items cover anxious mood, tension, fears, insomnia, cognitive difficulty, depressed mood, muscular symptoms, sensory symptoms, cardiovascular, respiratory, gastrointestinal, genitourinary and autonomic symptoms, and behaviour observed at interview.
Two subscales are commonly used: psychic anxiety and somatic anxiety.
Administration
Clinician administered as a semi structured interview. Each item is rated from 0 (not present) to 4 (severe), based on the person's state over the past week together with behaviour observed during the interview.
Desired Audience
Adults with an established anxiety disorder. Hamilton's stated intent was severity measurement in people already diagnosed, not case finding.
The HAM-A splits psychic anxiety from somatic anxiety, which matters clinically. Two people with the same total can need very different treatment, and the split is what tells you which.
Considerations
It is a severity measure for people already diagnosed, not a screening or diagnostic instrument.
It overlaps substantially with depression, including items on depressed mood and insomnia, so it discriminates anxiety from depression poorly.
Two competing sets of severity bands circulate. Choose one, cite it, and do not mix them.
It requires a trained clinician. Self rated use is common but sits outside Hamilton's intent.
How to score the Hamilton Anxiety Rating Scale HAM-A
Conducting the assessment
The clinician rates 14 items from 0 to 4 based on the interview.
Interpretation
Items are summed to give a total from 0 to 56.
The empirically derived bands (Matza et al., 2010), which correspond closely to clinician global severity ratings, are:
7 or below none or minimal
8 to 14 mild
15 to 23 moderate
24 or above severe
The older, traditional convention treats a score above 17 as mild anxiety and 25 to 30 as moderate to severe. These two schemes are not interchangeable.
Clinical Considerations
Pick one banding scheme and apply it consistently. Mixing the traditional and the empirical bands makes scores incomparable over time.
Read the psychic and somatic subscales separately.
Because of the depression overlap, always interpret alongside a depression measure.
Hamilton Anxiety Rating Scale HAM-A use cases
Measuring anxiety severity in adults with a diagnosed anxiety disorder
Tracking response to treatment
Separating psychic from somatic anxiety
Clinical trials, where it is a standard outcome measure
Category
Anxiety
Research Summary
Hamilton, M. (1959). The assessment of anxiety states by rating. British Journal of Medical Psychology, 32(1), 50 to 55.
Matza, L. S., Morlock, R., Sexton, C., Malley, K., & Feltner, D. (2010). Identifying HAM-A cutoffs for mild, moderate, and severe generalized anxiety disorder. International Journal of Methods in Psychiatric Research, 19(4), 223 to 232.
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