Evidence on light therapy as preventive treatment for patients with a history of SAD is limited. Methodological limitations and the small sample size of the only available study have precluded review author conclusions on effects of light therapy for SAD. Given that comparative evidence for light therapy versus other preventive options is limited, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences.
Light therapy for preventing seasonal affective disorder
Nussbaumer, B., Kaminski-Hartenthaler, A., Forneris, CA., Morgan, L., Sonis, JH., Gaynes, BN., ... Gartlehner, G. (2015). Light therapy for preventing seasonal affective disorder. Cochrane Database of Systematic Reviews, 11, CD01269. https://doi.org/10.1002/14651858.CD011269.pub2