Optimizing Long-Term Outcomes for Winter Depression With CBT-SAD and Light Therapy

Inclusion Criteria: * Principle DSM-5 diagnosis of Major Depression, Recurrent, with Seasonal Pattern. -Meet Structured Interview Guide for the Hamilton Rating Scale for Depression-Seasonal Affective Disorder Version (SIGH-SAD) criteria for a current SAD episode (see below). * No use or stable use of antidepressants (i.e., a consistent dose of the same medication maintained for \> 4 weeks with no plans to change). Exclusion Criteria: * Current or past light therapy or CBT for SAD. * Presence of a comorbid Axis I disorder that requires immediate treatment (i.e., bipolar disorder, psychotic disorders, substance use disorder). * Acute and serious suicidal intent. * Planned absences of \>1 week from the area through March. * History of conditions that are known contra-indications to LT, including conditions associated with toxicity of bright light to the retina (i.e., macular degeneration or any retinopathy).