LIGHT THERAPY FOR SEASONAL AFFECTIVE DISORDER: THE EFFECTS OF TIMING
British Journal of Psychiatry (1995)
January 1, 1995
Y. Meesters, J.H.C. Jansen, D.G.M. Beersma, A.L. Bouhuys and R.H. Van Den Hoofdakker
British Journal of Psychiatry (1995), 166, 607-612
Background. Sixty-eight patients with seasonal affective disorder participated in a 10000-lux light treatment study in which two questions were addressed: do response rates differ when the light is applied at different times of the day and does short-term rank ordering of morning and evening light influence response rates?
Method. Three groups of patients received a 4-day light treatment: (I) in the morning (8.00-8.30 a.m., n=14), (II) in the afternoon (1.00-1.30 p.m., n=15) or (III) in the evening (8.00-8.30 p.m., n=12). Two additional groups of patients received two days of morning light treatments followed by two days of evening light (IV, n=13), or vice versa (V, n=14).
Results. Response rates for groups I, II and III were 69, 57 and 80% respectively, with no significant differences between them. Response rates for groups IV and V were 67 and 50% respectively; this difference was not significant and these percentages did not differ significantly from those of groups I and III.
Conclusions. The results indicate that the timing of light treatment is not critical and that short-term rank ordering of morning and evening light does not influence therapeutic outcome.