Pathophysiological mechanism of seasonal affective disorder.
Despite the long history in medicine, the pathophysiological mechanism(s) of seasonal affective disorder (SAD) remain largely unknown. By employing a meta-analytic methodology, the authors of this study attempted to verify the validity of different pathophysiological mechanism(s) proposed for SAD. The findings showed that for phototherapy of medium light intensity, a combination of morning-evening therapy regime yielded the best therapeutic effect, and the antidepressant effect of the morning-evening light regime was superior to a single pulse of light administered at other times of day. Furthermore, the data showed that the antidepressant effect of a single pulse of light was similar for morning, midday, and evening light. These findings supported the photon-count hypothesis and refuted the proposed photoperiod, melatonin, and phase-shifting models of SAD.
Lee
T M
TM
Department of Psychology, University of Hong Kong, Hong Kong. tmclee@hkusua.hku.hk
Blashko
C A
CA
Janzen
H L
HL
Paterson
J G
JG
Chan
C C
CC
D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D008550:Melatonin / Q000502:physiology*; D010789:Phototherapy; D016574:Seasonal Affective Disorder / Q000503:physiopathology* / Q000523:psychology / Q000628:therapy; D016896:Treatment Outcome
D008550:Melatonin