A six-item subjective depression scale is a suitable companion for the six-item Hamilton Depression Rating Scale

Objective:Major depressive disorder (MDD) is better described when both objective and subjective assessments are acquired. We developed a six-item subjective depression scale (SDS6) to accompany the classic objective six-item Hamilton Depression Rating Scale (HAMD6) as an adjuvant.

Method: Items were adopted from the HAMD6, and anchor points were placed either side of ascending numbers in boxes - subjects indicated their experience by ticking appropriate box. Data was collected in a transcranial magnetic stimulation (TMS) unit treating major depressive disorder (MDD) in adults, using naturalistic, quality assurance studies, in which pre- and post-treatment HAMD6 and SDS6 scores were routinely collected in two streams (acute and maintenance treatment). The two scales were correlated using the Spearman rank correlation approach, as the two scales (although numerical) were obtained by qualitative rather than quantitative ratings.

Results: 61 patients came from two streams and the total number of pairs for correlation was 188. The Spearman rank correlation coefficient between the two scales is 0.76 (ci 0.69 to 0.83), which is 'strong'.

Conclusion: The SDS6 scores show a strong correlation with the HAMD6 scores, indicating the former subjective tool is a valid measure of the core aspects measured by the latter objective tool. Thus, these tools are useful companions.