Evidence-Based Reviews

SAD: Is seasonal affective disorder a bipolar variant?

Current Psychiatry. 2010 February;9(2):43-54

References

1. American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 4th ed, text rev. Washington, DC: American Psychiatric Association; 2000.

2. Lam RW, Levitt AJ. eds. Clinical guidelines for the treatment of seasonal affective disorder. Vancouver, BC: Clinical and Academic Publishing; 1999.

3. Rosenthal NE, Sack DA, Gillin JC, et al. Seasonal affective disorder. A description of the syndrome and preliminary findings with light therapy. Arch Gen Psychiatry. 1984;41(1):72-80.

4. Michalak EE, Wilkinson C, Hood K, et al. Seasonal and nonseasonal depression: how do they differ? Symptom profile, clinical and family history in a general population sample. J Affect Disord. 2002;69(1-3):185-192.

5. Goodwin FK, Jamison KR. Manic-depressive illness: bipolar disorders and recurrent depression. 2nd ed. New York, NY: Oxford University Press; 2007.

6. Sohn CH, Lam RW. Treatment of seasonal affective disorder: unipolar versus bipolar differences. Curr Psychiatry Rep. 2004;6(6):478-485.

7. Goikolea JM, Colom F, Martinez-Aran A, et al. Clinical and prognostic implications of seasonal pattern in bipolar disorder: a 10-year follow-up of 302 patients. Psychol Med. 2007;37:1595-1599.

8. Kessler RC, Zhao S, Blazer DG, et al. Prevalence, correlates, and course of minor depression and major depression in the National Comorbidity Survey. J Affect Disord. 1997;45(1-2):19-30.

9. Modell JG, Rosenthal NE, Harriett AE, et al. Seasonal affective disorder and its prevention by anticipatory treatment with bupropion XL. Biol Psychiatry. 2005;58:658-667.

10. Cassidy F, Carroll BJ. Seasonal variation of mixed and pure episodes of bipolar disorder. J Affect Disord. 2002;68:25-31.

11. Shin K, Schaffer A, Levitt AJ, et al. Seasonality in a community sample of bipolar, unipolar and control subjects. J Affect Disord. 2005;86:19-25.

12. Wood J, Birmaher B, Axelson D, et al. Replicable differences in preferred circadian phase between bipolar disorder patients and control individuals. Psychiatry Res. 2009;166(2-3):201-209.

13. Soreca I, Frank E, Kupfer DJ. The phenomenology of bipolar disorder: what drives the high rate of medical burden and determines long-term prognosis? Depress Anxiety. 2009;26(1):73-82.

14. Terman M, Terman J, Rafferty B. Experimental design and measures of success in the treatment of winter depression by bright light. Psychopharmacol Bull. 1990;26(4):505-510.

15. Goel N, Terman M, Terman JS, et al. Summer mood in winter depressives: validation of a structured interview. Depress Anxiety. 1999;9:83-91.

16. Denicoff KD, Leverich GS, Nolen WA, et al. Validation of the prospective NIMH-Life-Chart Method (NIMH-LCM-p) for longitudinal assessment of bipolar illness. Psychol Med. 2000;30:1391-1397.

17. Ghaemi SN, Miller CJ, Berv DA, et al. Sensitivity and specificity of a new Bipolar Spectrum Diagnostic Scale. J Affect Disord. 2005;84:273-277.

18. Phelps J, Angst J, Katzow J, et al. Validity and utility of bipolar spectrum models. Bipolar Disord. 2008;10:179-193.

19. Williams JB, Link MJ, Rosenthal NE, et al. Structured Interview Guide for the Hamilton Depression Rating Scale - Seasonal Affective Disorder Version (SIGH-SAD). New York, NY: New York State Psychiatric Institute; 1992.

20. Wu JC, Kelsoe JR, Schachat C, et al. Rapid and sustained antidepressant response with sleep deprivation and chronotherapy in bipolar disorder. Biol Psychiatry. 2009;66(3):298-301.

21. 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;162(4):656-662.

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23. Eastman CI, Young MA, Fogg LF, et al. Bright light treatment of winter depression: a placebo-controlled trial. Arch Gen Psychiatry. 1998;55(10):883-889.

24. Lewy AJ, Bauer VK, Cutler NL, et al. Morning vs evening light treatment of patients with winter depression. Arch Gen Psychiatry. 1998;55(10):890-896.

25. Sit D, Wisner KL, Hanusa BH, et al. Light therapy for bipolar disorder: a case series in women. Bipolar Disord. 2007;9:918-927.

26. Goodwin GM. Evidence-based guidelines for treating bipolar disorder: revised second edition—recommendations from the British Association for Psychopharmacology. J Psychopharmacol. 2009;23(4):346-388.

27. 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;163:805-812.

28. Pjrek E, Konstantinidis A, Assem-Hilger E, et al. Therapeutic effects of escitalopram and reboxetine in seasonal affective disorder: a pooled analysis. J Psychiatr Res. 2009;43(8):792-797.

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Clinical Point

For treating SAD, mood stabilizers with antidepressant effects, such as lamotrigine or lithium, are preferred for maintenance

Year-round mood-stabilizer treatment is indicated to minimize the risk of mood episodes in BD SP, especially in patients with BD I. When treating SAD, mood stabilizers with antidepressant effects—such as lamotrigine or lithium (for maintenance), and quetiapine or aripiprazole (for acute treatment)—are preferable to agents without an antidepressant effect in monotherapy. More-sedating mood stabilizers (such as valproate or carbamazepine) likely would not be as beneficial as less-sedating agents, considering that patients with SAD frequently experience fatigue.

Because of the lack of adequate clinical trials of treatments for BD SP, we suggest that clinicians choose medications and follow algorithms relevant to BD without a seasonal specifier. Use similar schedules and dosages, with individual tailoring.^5,26

Antidepressants that have shown efficacy in MDD SP include fluoxetine, bupropion, citalopram, and sertraline.^6,9,27-29 For patients with BD SP, we initiate antidepressants when:

light treatment fails
the patient is unable to travel to the south
light treatment is not available (often because patients cannot afford the cost, which is not covered by insurance)
patient lacks time for light treatment.

An additional important consideration is history of response (such as a patient who did not respond well to light therapy in the past but responded very well to a particular antidepressant).

No studies have compared antidepressant classes or individual medications for MDD SP. Clinical wisdom is to base the antidepressant choice, dosages, decision points of when to switch, and schedule of switching (cross-tapering) on individual patients’ symptom clusters and comorbid conditions as well as the medication’s side effects.

Prophylactic treatment with bupropion would seem an appropriate initial choice for a prototypical SAD patient, considering this medication’s more activating effects and FDA approval for SAD treatment.⁹ For the minority of patients with SAD who present with agitation and increased sleepiness, a slightly sedating selective serotonin reuptake inhibitor such as citalopram would make more sense as a first-line treatment. Finally, we would recommend sertraline for patients with marked anxiety—especially panic attacks or obsessive-compulsive symptoms—but without insomnia.

For specific dosages, rely on the literature of treating nonseasonal depression (unipolar or bipolar). It is important to define decision-making points for dosage increases, augmentation, switching to another antidepressant, and cross-tapering, similar to how you would address a nonseasonal depression, typical or atypical.

In our view, treating a patient with BD I SP with an antidepressant alone—without a mood stabilizer—is almost always wrong. For BD II SP we leave it to the clinician to decide, based on individual patients, clinical experience, and ideally in consultation with a peer.

Seasonal dosages. You may wish to seasonally vary medications and dosages for patients with BD SP. Although no strong evidence exists, we recommend 2 options:

Clinical Point

We do not taper antidepressants before daylight saving time, and we always consider stressors in our patients’ lives

Consider increasing mood-stabilizing medication in spring and summer, with a reduction (but no tapering for BD I) in fall and winter.
Consider a complete antidepressant taper 2 weeks after daylight saving time begins in spring; taper under increased observation and not faster than 6 weeks, with close attention to emerging symptoms of depression or antidepressant withdrawal.

We do not taper antidepressants before daylight saving time, and we always consider additional stressors, losses, and challenges in our patients’ lives before tapering antidepressants in spring or summer. We also assess and monitor compliance.

Psychotherapy. Referral can be made to clinicians trained in CBT for patients with a seasonal pattern and interpersonal and social rhythm therapy (IPSRT) for BD. Integrative models for SAD and BD propose that psychological and biologic vulnerability factors interact with environmental events (such as winter season or disruption of daily routine) to trigger mood episodes.

CBT adapted for SAD targets mal-adaptive thinking and behavioral disengagement through cognitive therapy and behavioral activation to counteract SAD symptoms.^30,31 Preliminary trials by our group suggest that CBT for MDD SP is an effective acute treatment³⁰ and may prevent future episodes.³²

IPSRT is an adaptation of interpersonal psychotherapy that aims to stabilize social relationships and rhythms in BD.³³ IPSRT posits that irregularity in daily routines leads to circadian dysregulation, precipitating mood episodes in persons vulnerable to BD.³⁴ The degree of regularity in social rhythms achieved in IPSRT is associated with reduced likelihood of recurrence post-treatment.³⁴ If stabilizing social rhythms has a similar effect of regulating circadian rhythms in SAD, IPSRT may be effective in treating BD SP.

Table 2