Use the HAM-A in adults and adolescents with suspected or established anxiety disorders to rate symptom severity over the past week and to monitor change with treatment, rather than as a stand-alone diagnostic or screening tool.

Developed by Max Hamilton in 1959 for adults with anxiety states in psychiatric settings, as a clinician-rated measure of anxiety severity rather than a diagnostic instrument.
The 14 items cover both psychic anxiety (items 1–6 and 14) and somatic/autonomic symptoms (items 7–13), allowing separate subscale scores that often load on distinct factors.
Psychometric studies in mixed anxiety and depressive samples report acceptable inter-rater reliability and sensitivity to change, but limited internal structure and difficulty separating anxiolytic from antidepressant effects, particularly for somatic items influenced by medication side effects and physical illness.
In a cohort of 257 adolescents aged 12–18 years from clinical and community settings, the HAM-A showed reliability and construct validity comparable to adult samples, supporting its use as a global clinician rating of adolescent anxiety.
Severity bands used in practice vary; this calculator uses one commonly cited grouping, while other work (including generalised anxiety disorder trials) has proposed alternative ranges, so scores should be interpreted as approximate severity categories rather than strict diagnostic thresholds.
The scale predates modern diagnostic criteria for generalised anxiety disorder and under-represents pathological worry; it does not distinguish well between anxiety and depressive symptoms, so it is best used alongside structured diagnostic assessment, functional impact and risk.

The primary source or current guidance provides the model definition, source population and supporting evidence.

Hamilton Anxiety Rating Scale (HAM-A)