Bright light therapy for seasonal affective disorder in Israel (latitude 32.6°N): a single case placebo-controlled study

Moscovici L. Bright light therapy for seasonal affective disorder in Israel (latitude 32.6°N): a single case placebo-controlled study.

ABSTRACT

Introduction: We describe a patient diagnosed as having seasonal affective disorder (SAD, winter depression), an unlikely condition in Israel (latitude 32.6°N), a country with relatively minor daylight photoperiodic changes between seasons.

Method: Case report.

Results: A 46-year-old woman with a clinical picture of depression (Diagnostic and Statistical Manual of Mental Disorders diagnostic criteria for 'major depression with seasonal pattern') reacted positively to 3 weeks of daily bright light therapy of 10 000 lux/wide spectrum. She was asked to wear dark sunglasses during placebo sessions to accommodate an A-B-C single-case-design. The intervention resulted in an improvement of 74–80% in the Hamilton anxiety and depression scales (clinician-rated) and the Beck depression inventory, similar to results obtained in high latitude regions. The depression and anxiety levels returned close to baseline levels following 1 week of the placebo intervention.

Conclusion: Seasonal affective disorder is apparently not limited to certain latitudes. The effect of light therapy was short-lived after discontinuation of the treatment, with rapid relapse occurring in the placebo phase.