A Systematic Review of the Clinimetric Properties of the 6-Item Version of the Hamilton Depression Rating Scale (HAM-D<sub>6</sub>)

In a study aimed at identifying the items carrying information regarding the global severity of depression, the 6-item Hamilton Depression Rating Scale (HAM-D6) was derived from the original 17-item version of the scale (HAM-D17). Since then, the HAM-D6 has been used in a wide range of clinical studies. We now provide a systematic review of the clinimetric properties of HAM-D6 in comparison with those of HAM-D17 and the Montgomery Asberg Depression Rating Scale (MADRS).We conducted a systematic search of the literature in PubMed, PsycInfo, and EMBASE databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline. Studies reporting data on the clinimetric validity of the HAM-D6 and either the HAM-D17 or MADRS in non-psychotic unipolar or bipolar depression were included in the synthesis.The search identified 681 unique records, of which 51 articles met the inclusion criteria. According to the published literature, HAM-D6 has proven to be superior to both HAM-D17 and MADRS in terms of scalability (each item contains unique information regarding syndrome severity), transferability (scalability is constant over time and irrespective of sex, age, and depressive subtypes), and responsiveness (sensitivity to change in severity during treatment).According to the published literature, the clinimetric properties of HAM-D6 are superior to those of both the HAM-D17 and MADRS. Since the validity of HAM-D6 has been demonstrated in both research and clinical practice, using the scale more consistently would facilitate translation of results from one setting to the other.