A Review of Studies of the Hamilton Depression Rating Scale in Healthy Controls: Implications for the Definition of Remission in Treatment Studies of Depression

The Hamilton Rating Scale for Depression (HRSD) is the most commonly used symptom severity scale to evaluate the efficacy of antidepressant treatment. On the basis of an expert consensus panel, an HRSD score of ≤7 was recommended as a cutoff to define remission. Since that recommendation, little empirical work has been conducted to confirm the validity of this threshold. One approach toward determining a cutoff score for defining remission is to establish the range of values for healthy controls. We therefore conducted a literature review of studies of the HRSD in healthy controls to determine the normal range of values. Studies of the HRSD in healthy control groups were identified in two ways. First, a MEDLINE search for the years 1966 to 2002 was conducted using the key words Hamilton, depression, and controls, and articles were reviewed. Second, the 69 studies included in two review articles written by the authors were examined. We identified 27 studies that included data on the HRSD for 1014 healthy controls. Across all studies, the weighted mean (SD) HRSD score, adjusting for sample size, was 3.2 (3.2; 95% CI, 3.0 to 3.4). HRSD scores were similar in geriatric and nongeriatric samples, and in men and women. Because HRSD scores in healthy controls are more likely to follow a skewed than a normal distribution, based on a mean of 3.2 and a SD of 3.2, at least 84% of healthy controls scored 7 or less on the HRSD, and 97.5% scored 10 or less. Thus, these results can be taken as support for the recommended cutoff of 7 on the HRSD to define remission. The results can also be used for normative comparisons in which posttreatment group mean scores are compared with mean scores from normative samples.