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Dose‐response relationship of phototherapy for seasonal affective disorder: a meta‐analysis
Author(s) -
Lee T. M. C.,
Chan C. C. H.
Publication year - 1999
Publication title -
acta psychiatrica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.849
H-Index - 146
eISSN - 1600-0447
pISSN - 0001-690X
DOI - 10.1111/j.1600-0447.1999.tb07236.x
Subject(s) - light therapy , meta analysis , rating scale , antidepressant , psychology , hamilton rating scale for depression , analysis of variance , clinical psychology , depression (economics) , therapeutic effect , light intensity , medicine , psychiatry , major depressive disorder , anxiety , developmental psychology , mood , physics , optics , economics , macroeconomics
Objective: The therapeutic effect of phototherapy for seasonal affective disorder (SAD) has been widely investigated. However, the antidepressant effect of various light intensities is inconclusive. The purpose of this study was to evaluate the dose‐response relationship of phototherapy for SAD. Method: A meta‐analytical methodology was applied to 39 studies of phototherapy for SAD. The studies collected were screened for study quality by a threats‐to‐validity method before inclusion. The fixed‐effects‐model analysis of variance procedures were used for data analysis. Results: The results indicated that different light intensities produced different effects in reducing the typical symptoms, as measured by the Hamilton Depression Rating Scale, of patients with SAD. However, no significant differences in these effects were revealed between strong, medium and dim light in reducing the atypical symptoms of patients. Conclusion: These findings showed that light intensity varied positively with the antidepressant effect for typical but not for atypical symptoms of SAD, suggesting that light intensity tended to have different therapeutic effects on the typical and atypical symptoms of SAD.