Psych · General adult psychiatry — mood disorders
Seasonal and atypical depression
Also known as Seasonal affective disorder · SAD · Winter depression · Seasonal pattern specifier · Atypical features depression · Depression with atypical features · Reverse vegetative depression
Exam-exhaustive fellowship reference on seasonal pattern major depression (SAD) and depression with atypical features — DSM-5-TR/ICD framing, circadian mechanisms, light therapy parameters, Can-SAD, bupropion XL prevention, SSRIs, CBT-SAD, MAOI historical evidence, differentials, and guideline deltas. FRANZCP-primary, globally tagged.
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Red flags
- Active suicidal ideation, plan or attempt in seasonal or atypical depression — same intensity of risk response as nonseasonal MDD; seasonality is not reassurance
- Hypomania or mania after light therapy or antidepressant — stop/adjust, re-screen bipolar spectrum, stabilise mood
- Severe winter depression with poor intake, psychosis or catatonic signs — urgent escalation; do not rely on light box alone
- Bupropion in high seizure-risk patients or abrupt alcohol/benzodiazepine withdrawal — avoid or specialist only
- MAOI plus serotonergic drug or tyramine-rich diet breach — hypertensive crisis or serotonin toxicity risk
- Ocular disease or photosensitising medication without review before high-intensity bright light therapy
Meet the patient
A 33-year-old theatre nurse books in every April. By May she is sleeping eleven hours, eating toast at midnight, and calling in sick. By October she is running half-marathons. This is her fourth winter like this and her second GP.[8][11]
Her referral says "winter blues, wants a light box." Her mood chart, drawn across two years in your consulting room, says something else: two full major depressive episodes, both autumn-onset, both remitting in spring, and nothing in between.[8][11]
Two axes decide her plan. When does it come (course) and which way do the vegetative signs point (features)? Confuse them and you will treat the wrong thing with the right device.[8][16][17]
References20ShowHide
- [1]Golden RN, Gaynes BN, Ekstrom RD, et al. The efficacy of light therapy in the treatment of mood disorders: a review and meta-analysis of the evidence Am J Psychiatry, 2005.PMID 15800134
- [2]Lam RW, Levitt AJ, Levitan RD, et al. The Can-SAD study: a randomized controlled trial of the effectiveness of light therapy and fluoxetine in patients with winter seasonal affective disorder Am J Psychiatry, 2006.PMID 16648320
- [3]Modell JG, Rosenthal NE, Harriett AE, et al. Seasonal affective disorder and its prevention by anticipatory treatment with bupropion XL Biol Psychiatry, 2005.PMID 16271314
- [4]Gartlehner G, Nussbaumer-Streit B, Gaynes BN, et al. Second-generation antidepressants for preventing seasonal affective disorder in adults Cochrane Database Syst Rev, 2019.PMID 30883669
- [5]Nussbaumer-Streit B, Forneris CA, Morgan LC, et al. Light therapy for preventing seasonal affective disorder Cochrane Database Syst Rev, 2019.PMID 30883670
- [6]Rohan KJ, Mahon JN, Evans M, et al. Randomized Trial of Cognitive-Behavioral Therapy Versus Light Therapy for Seasonal Affective Disorder: Acute Outcomes Am J Psychiatry, 2015.PMID 25859764
- [7]Rohan KJ, Meyerhoff J, Ho SY, et al. Outcomes One and Two Winters Following Cognitive-Behavioral Therapy or Light Therapy for Seasonal Affective Disorder Am J Psychiatry, 2016.PMID 26539881
- [8]Westrin A, Lam RW Seasonal affective disorder: a clinical update Ann Clin Psychiatry, 2007.PMID 18058281
- [9]Westrin A, Lam RW Long-term and preventative treatment for seasonal affective disorder CNS Drugs, 2007.PMID 17927295
- [10]Lewy AJ, Lefler BJ, Emens JS, et al. The circadian basis of winter depression Proc Natl Acad Sci U S A, 2006.PMID 16648247
- [11]Magnusson A, Partonen T The diagnosis, symptomatology, and epidemiology of seasonal affective disorder CNS Spectr, 2005.PMID 16041294
- [12]Magnusson A An overview of epidemiological studies on seasonal affective disorder Acta Psychiatr Scand, 2000.PMID 10721866
- [13]Quitkin FM, Stewart JW, McGrath PJ, et al. Phenelzine versus imipramine in the treatment of probable atypical depression: defining syndrome boundaries of selective MAOI responders Am J Psychiatry, 1988.PMID 3278631
- [14]Liebowitz MR, Quitkin FM, Stewart JW, et al. Antidepressant specificity in atypical depression Arch Gen Psychiatry, 1988.PMID 3276282
- [15]Jarrett RB, Schaffer M, McIntire D, et al. Treatment of atypical depression with cognitive therapy or phenelzine: a double-blind, placebo-controlled trial Arch Gen Psychiatry, 1999.PMID 10232298
- [16]Stewart JW Treating depression with atypical features J Clin Psychiatry, 2007.PMID 17348764
- [17]Malhi GS, Bell E, Bassett D, et al. The 2020 Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for mood disorders Aust N Z J Psychiatry, 2021.PMID 33353391
- [18]Kennedy SH, Lam RW, McIntyre RS, et al. Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 Clinical Guidelines for the Management of Adults with Major Depressive Disorder: Section 3. Pharmacological Treatments Can J Psychiatry, 2016.PMID 27486148
- [19]Ravindran AV, Balneaves LG, Faulkner G, et al. Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 Clinical Guidelines for the Management of Adults with Major Depressive Disorder: Section 5. Complementary and Alternative Medicine Treatments Can J Psychiatry, 2016.PMID 27486153
- [20]Kim K, Kim J, Jung S, et al. Global prevalence of seasonal affective disorder by latitude: A systematic review and meta-analysis J Affect Disord, 2025.PMID 40614973