Hospital room exposure to daylight and clinical improvement in unipolar depressed inpatients

Light therapy is an effective treatment for unipolar Major Depressive Episodes (MDE). Exposure to daylight, depending on hospital room orientation, could influence clinical improvement. We aim to show greater clinical improvement 1 month after venlafaxine treatment in depressed inpatients staying in South/East facing room compared to inpatients staying in North/West facing rooms. A nested case-control study was performed within the DEP-ARREST- CLIN, a prospective and monocentric cohort. We analyzed patients with a current MDE in the context of Major Depressive Disorder who stayed at least one month in either South/East or North/West facing hospital rooms. Clinical improvement was assessed with the Hamilton Depressive Rating Scale (HAMD-17) before and after 1 month of venlafaxine treatment. 44 patients were analyzed. The average HAMD-17 score at inclusion was 26.3 (±5.5). Clinical improvement of inpatients staying in South/East facing rooms (56.8 % HAMD-17 improvement) did not differ from inpatients staying in North/West facing rooms (65.6% HAMD-17 improvement, p=0.21) after 1 month of venlafaxine treatment. Subgroup analyses revealed no associations between clinical improvement and East vs West or South vs North facing rooms or winter vs summer inpatients. Limited sample size and non-randomized study. In our sample, we observed no association between room exposure to daylight and clinical improvement after treatment in unipolar depressed inpatients.