Light Therapy for Seasonal Affective Disorder the Effects of Timing

• Published in: British journal of psychiatry 1995-05, Vol.166 (5), p.607-612
• Main Authors: Meesters, Y., Jansen, J. H. C., Beersma, D. G. M., Bouhuys, A. L., Van Den Hoofdakker, R. H.
• Format: Article
• Language: English
• Subjects: Adult; Ambulatory Care; Circadian Rhythm; Factors; Female; Humans; Light; Light therapy; Male; Middle Aged; Personality Inventory; Phototherapy - methods; Response rates; Seasonal affective disorder; Seasonal Affective Disorder - psychology; Seasonal Affective Disorder - therapy; Seasonal affective disorders; Short term; Timing; Treatment; Treatment Outcome
• ISSN: 0007-1250; 1472-1465
• DOI: 10.1192/bjp.166.5.607

Sixty-eight patients with seasonal affective disorder participated in a 10,000-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? 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 treatment followed by two days of evening light (IV, n = 13) or vice versa (V, n = 14). 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. 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.