Among patients with seasonal affective disorder, how does light therapy compare with fluoxetine for clinical response and remission rates?
In this small study of patients with major depressive episodes with a winter pattern, light therapy was similar to fluoxetine in terms of reducing patients' self-reported depression scores. Light therapy is a reasonable first-line therapy for seasonal affective disorder.
Trials in the late 1990s demonstrated the efficacy of light therapy in the treatment of seasonal affective disorder (SAD). Large head-to-head comparisons of light therapy versus antidepressants were lacking.
Published in 2006, the Can-SAD study randomized 96 patients with SAD to light therapy or fluoxetine therapy in a double-blind fashion. Of those randomized, 81 completed the study. Patients at baseline were severely depressed by the Hamilton Depression Rating scale with a mean score of 30. At 8 weeks of follow-up, both groups had improvements in their depression, with scores correlating with mild severity (mean score of 12). Both groups experienced a similar frequency of adverse events, with about a third of each group experiencing a self-reported severe adverse event. The SSRI group had more frequent reports of agitation, sleep disturbances, and palpitations. This trial is limited by is under-reporting of trial design (eg, goal enrollment based upon power calculations), small size, and incomplete reporting of adverse event details.
A 2011 Cochrane meta-analysis found light therapy to be equivalent to SSRI therapy in SAD, though this was based on two trials only.
American Psychiatric Association Major Depression (2010, adapted)
- Light therapy appears to be effective for SAD and nonseasonal MDD. It is low-risk and low-cost. (No specific grading or recommendations given.)
- Multicenter, double-blind, randomized, controlled trial
- Light therapy (n=41)
- Fluoxetine (n=40)
- Setting: Four centers in Canada
- Enrollment: Three winter seasons (September 15-February 15) 2000-2003
- Follow-up: 8 weeks
- Analysis: Intention-to-treat
- Primary outcome: Hamilton Depression Scale score
- 18-65 years
- Major depressive episodes with a winter pattern as determined by a modified Structured Clinical Interview for DSM-IV
- Hamilton Depression Rating Scale score ≥20 if 17 items or ≥14 if 17 items if score on 24 item was ≥23
- Pregnant or lactating
- Sexually active women without effective contraception
- Serious suicidal risk by the judgment of the investigator
- Meeting DSM-IV criteria for organic mental disorders, substance use disorders in the prior year, schizophrenia, paranoid disorder, delusional disorder, psychotic disorder, bipolar I disorder, panic disorder, GAD not otherwise concurrent with major depressive episodes
- Unstable, serious medical illness
- Retinal disorder precluding treatment with light therapy
- Severe allergies or multiple drug adverse reactions
- Use of other psychotropic medications (including St. John's wort or melatonin)
- Beta blocker therapies
- Use of antidepressants or mood-altering medications in prior week
- Prior treatment with fluoxetine or light therapy
- CBT or interpersonal psychotherapy in prior 3 months
- "Shift work" or traveling south during the protocol
From the light therapy group.
- Demographics: Female 64.6%, age 42.3 years, married 50%
- Psychiatric diagnoses and history: Bipolar II disorder 4.2%, prior psychiatric contact 27.1%, prior hospitalization 4.2%, family history of mood disorders 41.7%, previous antidepressants 45.8%, previous psychotherapy 22.9%
- SAD details: Atypical features 31.3%, prior episodes 11, CGI severity 4.2, Global Assessment of Functioning score 57.2
- Hamilton Depression Rating Scale score:
- Total (24 items): 30.2
- Typical symptoms (17 items): 17.3
- Atypical symptoms (7 items): 13.0
- Beck Depression Inventory II: 24.5
- 1 week of sleep adjustment in which patients were instructed to sleep only between 10PM and 8AM
- Patients who had <25% improvement in their depression scores were randomized to a group for 8 weeks:
- Light therapy - 10,000 lux fluorescent light box at 14 inches from the corena for 30 min between 7-8AM
- SSRI - Fluoxetine 20 mg PO qday between 7-8AM
- Both groups were given placebo agent for the other arm
Presented as light therapy vs. fluoxetine at 8 weeks except where noted.
- Hamilton Depression Rating Scale score
- Total score: ≤9 not depressed; 10-19 mildly depressed; 20-29 moderately depressed; ≥30 severely depressed.
- Total (24 items): 11.6 vs. 11.6 (NS)
- Typical symptoms (17 items): 6.4 vs. 6.5 (NS)
- Atypical symptoms (7 items): 5.2 vs. 5.1 (NS)
- Beck Depression Inventory-I
- 0-13 minimal depression; 14-19 mild depression, 20-28 moderate depression; 29-62 severe depression.
- 9.1 vs. 11.2
- Primary outcome at 1 week
- Total (24 items): 20.7 vs. 22.2 (P<0.05)
- 77% vs. 75%
- Severe, by self-rating: 33% vs. 35%
- Any increase from baseline
- Abdominal pain: 6.3% vs. 8.3%
- Nausea: 4.2% vs. 10.4%
- Diarrhea: 4.2% vs. 10.4%
- Constipation: 8.3% vs. 6.3%
- Decreased appetite: 14.6% vs. 14.6%
- Increased appetite: 8.3% vs. 14.6%
- Weight loss: 2.1% vs. 6.3%
- Anxiety: 12.5% vs. 25.0%
- Nervousness: 12.5% vs. 10.4%
- Agitation: 0% vs. 12.5% (P<0.05)
- Tremor: 2.1% vs. 6.3%
- Irritability: 4.2% vs. 8.3%
- Sleepiness: 8.3% vs. 12.5%
- Increased sleep: 12.5% vs. 18.8%
- Decreased sleep: 22.9% vs. 20.8%
- Sleep disturbance: 2.1% vs. 29.2% (P<0.01)
- Headache: 16.7% vs. 10.4%
- Decreased sex drive: 14.6% vs. 16.7%
- ED in males: 4.7% vs. 6.3%
- Delayed orgasm in women: 0% vs. 6.3%
- Faint feeling: 6.3% vs. 0%
- Palpitations: 0% vs. 10.4% (P<0.05)
- Sweating: 6.3% vs. 10.4%
- Muscle pain: 12.5% vs. 12.5%
- Weakness/fatigue: 16.7% vs. 16.7%
- Rash: 0% vs. 6.3%
- Dry mouth: 18.8% vs. 14.6%
- Flushing: 6.3% vs. 4.2%
- 8 vs. 7 participants (P=1.00)
- Due to an adverse event: 1 vs. 2 participants (P=1.00)
- Small study
- The authors did not report their power calculation or if they met their enrollment goal
- No report of what constituted a severe adverse event
- Canadian Institutes of Health Research (CIHR) grant
- CIHR/Wyeth Postdoctoral Fellowship Award
- Uplift Technologies provided light therapy boxes
- Authors with multiple financial disclosures
- Terman M, et al. "A controlled trial of timed bright light and negative air ionization for treatment of winter depression." Archives of General Psychiatry. 1998;55(10):875-882.
- Eastman CI et al. "Bright light treatment of winter depression: A placebo-controlled trial." Archives of General Psychiatry. 1998;55(10):883-889.
- Thaler K, et al. "Second-generation antidepressants for seasonal affective disorder." The Cochrane Database for Systematic Reviews. 2011;Dec 7(12):CD008591.
- Gelenberg AJ, et al. "Practice guideline for the treatment of patients with major depressive disorder. Third edition." PsychiatryOnline.org/guidelines. Published 2010-10. Accessed 2015-04-28.
- Hamilton Rating Scale for Depression. UMassMed.edu. Accessed 2015-04-28.
- Lam RW and Tam EM. "A clinician's guide to using light therapy." Online supplement. UBCMood.ca. Published 2009. Accessed 2015-04-28.
- Beck Depression Inventory-II, PsychCongress Network. Accessed 2015-04-28.