Pathophysiological mechanism of seasonal affective disorder

Tatia M.C. Lee, Carl A. Blashko, Henry L. Janzen, John G. Paterson, Che Hin Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

51 Citations (Scopus)


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.
Original languageEnglish
Pages (from-to)25-38
Number of pages14
JournalJournal of Affective Disorders
Issue number1
Publication statusPublished - 1 Oct 1997

ASJC Scopus subject areas

  • Clinical Psychology
  • Psychiatry and Mental health


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