Canonical definition at Shrinktionary. This entry adds the depression-specific angle.
About this term
Sources
American Psychiatric Association. DSM-5-TR.
Rohan KJ, et al. Outcomes one and two winters following cognitive-behavioral therapy or light therapy for seasonal affective disorder. Am J Psychiatry. 2016.
Modell JG, et al. Seasonal affective disorder and its prevention by anticipatory treatment with bupropion XL. Biol Psychiatry. 2005.
Lam RW, et al. Canadian Network for Mood and Anxiety Treatments (CANMAT) clinical guidelines: bright light therapy in major depressive disorder. Can J Psychiatry. 2016.
Seasonal depression, clinically called major depressive disorder with seasonal pattern, is a depressive episode that recurs at the same time each year, most often in fall and winter, with full remission in spring and summer. The pattern must repeat for at least two years to meet criteria.
What are the typical symptoms?+
In addition to standard depression symptoms, seasonal depression often includes oversleeping, increased appetite (especially for carbohydrates), weight gain, and a heavy, slowed feeling. Energy is low and motivation drops. The pattern usually begins in late fall as daylight shortens.
Does light therapy actually work?+
Yes. Bright light therapy, typically 10,000 lux for 20 to 30 minutes within an hour of waking, has evidence comparable to antidepressants for fall-onset seasonal depression. A standard light box, used on most days through the affected months, is the clinical recommendation.
When should I add medication or therapy?+
When light therapy alone isn't enough, when symptoms are moderate to severe, or when daily functioning is meaningfully affected, antidepressants (often an SSRI) and cognitive behavioral therapy adapted for seasonal depression (CBT-SAD) both have evidence. A combination is common in clinical practice.
Is summer-pattern seasonal depression a real thing?+
Yes, though it's less common than winter pattern. Summer-pattern seasonal depression can include insomnia, agitation, and reduced appetite rather than the oversleeping and overeating of winter pattern. Treatment is more often medication and therapy than light therapy.
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