Background and aim:
Improvement in patients admitted to inpatient wards with severe depression is slow, and such patients are often discharged with residual symptoms which put them at risk for relapse. New treatments that can speed up recovery are highly desired. This naturalistic follow-up study in a specialized affective disorders unit investigated the impact of daylight on the length of hospital stay and improvement of depression.
For a period of 1 year, we collected data on sociodemographics, length of stay, vitamin D, and depression severity for patients in an inpatient affective disorders unit. The ward is located with one facade that faces southeast (SE); the opposite one faces northwest (NW) and receives far less light and no direct sunlight during winter.
SE-facing rooms received far more daylight than NW-facing rooms. The length of stay was significantly lower in the SE rooms, i.e., 29.2 (±26.8) versus 58.8 (±42.0) days in the NW rooms (p = 0.01). There was a statistically nonsignificant greater reduction of 52.2% in depression severity for the patients staying in the SE rooms compared to 42.2% in the NW rooms, which may nevertheless be clinically relevant.
Due to the study design, no causality for the observed difference in length of stay can be given, but the results support findings in previous studies of the importance of architectural orientation providing natural daylight as a factor for improvement.