Early response to light therapy partially predicts long-term antidepressant effects in patients with seasonal affective disorder.
Sher L, Matthews JR, Turner EH, Postolache TT, Katz KS, Rosenthal NE.
Section on Biological Rhythms, National Institute of Mental Health, Bethesda, Md., USA.
J Psychiatry Neurosci. 2001 Sep;26(4):336-8.
OBJECTIVE: To determine if the antidepressant effect of 1 hour of light therapy is predictive of the response after 1 and 2 weeks of treatment in patients with seasonal affective disorder (SAD).
PATIENTS: Twelve patients with SAD.
SETTING: National Institutes of Health Clinical Center, Bethesda, Md.
INTERVENTIONS: Light therapy for 2 weeks.
OUTCOME MEASURES: Scores on the Seasonal Affective Disorder Version of the Hamilton Depression Rating Scale (SIGH-SAD) on 4 occasions (before and after 1 hour of light therapy and after 1 and 2 weeks of therapy) in the winter when the patients were depressed. Change on typical and atypical depressive scores at these time points were compared.
RESULTS: Improvement of atypical depressive symptoms after 1 hour of light therapy positively correlated with improvement after 2 weeks of therapy.
CONCLUSION: In patients with SAD, the early response to light therapy may predict some aspects of long-term response to light therapy, but these results should be treated with caution until replicated.