503 Limited evidence for light therapy as preventive treatment for seasonal affective disorder

June 02, 2017

written by Brian R McAvoy

Clinical question
How effective is light therapy in preventing seasonal affective disorder (SAD) in adults?

Bottom line
There is limited evidence on light therapy as a preventive treatment for patients with a history of SAD. A single small study (46 participants) showed both bright white light and infrared light reduced the incidence of SAD, numerically, compared with no light therapy, but the quality of evidence for all outcomes was very low. The study provided no information on side effects of light therapy.

Reasons for downgrading evidence quality included high risk of bias of the included study, imprecision and other limitations, such as self-rating of outcomes, lack of checking of compliance throughout the study duration and insufficient reporting of participant characteristics.

SAD is a seasonal pattern of recurrent major depressive episodes that most commonly occurs during autumn or winter, and remits in spring. The prevalence of SAD ranges from 1.5% to 9%, depending on latitude. The predictable seasonal aspect of SAD provides a promising opportunity for prevention.

Cochrane Systematic Review
Nussbaumer B et al. Light therapy for preventing seasonal affective disorder. Cochrane Reviews, 2015, Issue 11. Art. No.: CD011269.DOI: 10.1002/14651858. CD011269.pub2. This review contains 1 study involving 46 participants.

Pearls are an independent product of the Cochrane primary care group and are meant for educational use and not to guide clinical care.