Effect of bright white light on non-seasonal depressive disorder

In previous research, the therapeutic effect of bright white light for so so-called seasonal affective disorder was clearly confirmed. The aim of the present study was to evaluate possible beneficial effects of bright white light in non-seasonal depression. 30 patients fulfilling RDC-criteria for major depressive disorder were randomly assigned to a 7 day exposure from 7.20 to 9.20 a.m. The degree of illness was ascertained both objectively with observer rating scales (Hamilton Depression Scale, AMDP-system) and through self-rating scales (Complaint List and Depression Scale by von Zerssen). No difference was noted between bright light and dim light though a significant reduction of depressive symptomatology was observed for all patients during the treatment. These results were consistent for both observer rating and self-rating. In conclusion, bright white light has no superior effect as compared to dim light exposure in non-seasonal depression.