The most common way to provide bright light therapy to Swedish patients with Seasonal Affective Disorder (SAD), is treatment in a light therapy room. Since few studies have evaluated treatment provided in this setting and few have evaluated the effect of bright light in sub-clinical SAD (S-SAD), such a study including a one-month follow-up was designed.
Methods: Fifty adults recruited from a previous prevalence study and clinically assessed as having SAD or S-SAD, were randomized to treatment in a light room or to a three-week waiting-list control group. The Hamilton Depression Rating Scale-Seasonal Affective Disorders Self-rating 29-items Version (SIGH-SAD/SR) was used to measure depressive mood at baseline, directly following treatment and at the one-month follow-up.
Results: ANCOVA with adjustment for baseline depression score, showed a significant main effect for the light room therapy group (p<0.001). Fifty-four percent (n=13/24) improved >/=50% while no such improvement was seen in the control condition (n=0/24). After merging the two groups, repeated measures ANOVA confirmed the experimental analysis (p<0.001). At the one-month follow-up, 83.0% (n=39/47) had improved >/=50% and 63.8% (n=30/47) had normal depression scores i.e., [8 or less on a 17-point scale where 10-13 is mildly depressed].
Conclusions: Light room therapy was effective in reducing depressive symptoms in subjects with winter depressive mood. Results were maintained over a period of one month.
Source: Journal of Affective Disorders. Nov 27, 2007. [Epub ahead of print] PMID: 18053580, by Rastad C, Ulfberg J, Lindberg P. Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden; Center for Clinical Research Dalarna, Falun, Sweden.