Light therapy for seasonal affective disorder. The effects of timing.
BACKGROUND
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?


METHODS
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).


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.
Meesters
Y
Y
Academic Hospital Groningen, The Netherlands.
Jansen
J H
JH
Beersma
D G
DG
Bouhuys
A L
AL
van den Hoofdakker
R H
RH
D000328:Adult; D000553:Ambulatory Care; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010555:Personality Inventory; D010789:Phototherapy / Q000379:methods*; D016574:Seasonal Affective Disorder / Q000523:psychology / Q000628:therapy*; D016896:Treatment Outcome