Effects of light therapy on suicidal ideation in patients with winter depression

Background: Recent case reports suggest that some patients with seasonal affective disorder (SAD) may become suicidal after initial treatment with light therapy. This retrospective study sought to determine the effects of light therapy on suicidal ideation in patients with SAD. Method: The cases of 191 depressed patients with SAD by DSM-III-R or DSM-IV criteria treated with an open trial of morning light therapy using cool white fluorescent light boxes (2500 lux for 2 hours per day or 10,000 lux for 30 minutes per day) for 2 weeks were retrospectively analyzed. Patients had been rated before and after treatment with the expanded Hamilton Depression Rating Scale (SIGH-SAD). Results: Sixty-seven percent of patients were rated as clinical responders to light therapy. There was significant improvement in the SIGH-SAD suicide item score, with 45% of patients showing a reduction in score. Only 6 patients (3%) had slight worsening of suicide scores. No patients attempted suicide or discontinued light therapy because of emergent suicidality. Conclusion: Light therapy relieves suicidal ideation in patients with SAD consistent with overall clinical improvement. Emergence of suicidal ideas or behaviors is very uncommon with light therapy.