The aim of this study is to investigate the efficacy of bright light therapy in SAD. This is a placebo-controlled, double-blind randomized controlled trial (RCT).

Inclusion Criteria:

• a patient has, according to the DSM-IV-TR, a Major depression, recurrent episode, seasonal pattern, "moderate" or "severe" (classification code 296.32 and 296.33)
• HAMD-21 (included in the SIGH-SAD) sum score is ≥ 22
• patient is over 18 years
• patient can read and understand the subject information sheet
• patient has signed the informed consent form
• patient is not pregnant

Exclusion Criteria:

• patient has a lifetime psychotic disorder
• patient has a DSM-IV Axis I disorder other than some anxiety disorder evaluated by MINI
• patient has some DSM-IV-TR Axis II disorder, which is likely to interfere with the study treatment according to the investigator
• patient has alcohol or some other substance use dependence or misuse
• life-time suicide attempt, or any thought of suicide during the last month
• patients has some unstable somatic disorder
• patient uses some medication on regular basis
• patient uses some herbal psychotropic agencies
• patient is, in the opinion of the investigator, unsuitable for any reason
• patient is a member of the site personnel or their immediate families
• patient has had bright light therapy during the current episode
• patient has some eye disease (patient can, however, be myopic or hyperopic)