Bright light therapy is an evidence-based treatment for seasonal depression, but there is limited evidence for its efficacy in nonseasonal major depressive disorder (MDD).
To determine the efficacy of light treatment, in monotherapy and in combination with fluoxetine hydrochloride, compared with a sham-placebo condition in adults with nonseasonal MDD.
DESIGN, SETTING, AND PARTICIPANTS
Randomized, double-blind, placebo- and sham-controlled, 8-week trial in adults (aged 19-60 years) with MDD of at least moderate severity in outpatient psychiatry clinics in academic medical centers. Data were collected from October 7, 2009, to March 11, 2014. Analysis was based on modified intent to treat (randomized patients with ≥1 follow-up rating).
Patients were randomly assigned to (1) light monotherapy (active 10 000-lux fluorescent white light box for 30 min/d in the early morning plus placebo pill); (2) antidepressant monotherapy (inactive negative ion generator for 30 min/d plus fluoxetine hydrochloride, 20 mg/d); (3) combination light and antidepressant; or (4) placebo (inactive negative ion generator plus placebo pill).
MAIN OUTCOMES AND MEASURES
Change score on the Montgomery-Åsberg Depression Rating Scale (MADRS) from baseline to the 8-week end point. Secondary outcomes included response (≥50% reduction in MADRS score) and remission (MADRS score ≤10 at end point).
A total of 122 patients were randomized (light monotherapy, 32; fluoxetine monotherapy, 31; combination therapy, 29; placebo, 30). The mean (SD) changes in MADRS score for the light, fluoxetine, combination, and placebo groups were 13.4 (7.5), 8.8 (9.9), 16.9 (9.2), and 6.5 (9.6), respectively. The combination (effect size [d] = 1.11; 95% CI, 0.54 to 1.64) and light monotherapy (d = 0.80; 95% CI, 0.28 to 1.31) were significantly superior to placebo in the MADRS change score, but fluoxetine monotherapy (d = 0.24; 95% CI, −0.27 to 0.74) was not superior to placebo. For the respective placebo, fluoxetine, light, and combination groups at the end point, response was achieved by 10 (33.3%), 9 (29.0%), 16 (50.0%), and 22 (75.9%) and remission was achieved by 9 (30.0%), 6 (19.4%), 14 (43.8%), and 17 (58.6%). Combination therapy was superior to placebo in MADRS response (β = 1.70; df = 1; P = .005) and remission (β = 1.33; df = 1; P = .02), with numbers needed to treat of 2.4 (95% CI, 1.6 to 5.8) and 3.5 (95% CI, 2.0 to 29.9), respectively. All treatments were generally well tolerated, with few significant differences in treatment-emergent adverse events.
CONCLUSIONS AND RELEVANCE
Bright light treatment, both as monotherapy and in combination with fluoxetine, was efficacious and well tolerated in the treatment of adults with nonseasonal MDD. The combination treatment had the most consistent effects.
Turn towards the light
As we approach winter, the days get shorter and we find ourselves going to work and coming home in the dark. Research supports the use of therapeutic light for seasonal affective disorder (SAD), but what about using it to treat major depression when it is not winter? This study wanted to see if light therapy is beneficial in any season.
This study was a double-dummy design, which means that each participant in all four groups received both a pill (fluoxetine or placebo) and sat in front of a box (light or a negative ion generator). This controls for the nonspecific variables that can influence outcomes if everyone does not go through the procedure of taking a pill or sitting in front of a box.
The four groups consisted of placebo (placebo pill + ion generator), fluoxetine (med + ion generator), light (light box + placebo), and combination (fluoxetine + light) for 8 weeks. The 121 participants were randomized with only about 30 in each group, which was a limitation of this study. The light therapy consisted of 30 minutes daily between 7 and 8 AM, sitting within 14 inches (35.56 cm) inches of the box. The fluoxetine was dosed at 20 mg daily.
The light therapy was more effective than fluoxetine, and combining both was best for inducing remission, with a NNT of just 3.5.
Light therapy is thought to benefit depression by resynchronizing circadian rhythms and improving neurotransmitter dysfunction, but the underlying mechanism still remains entirely unclear.
I like it when there is good evidence for therapies that are effective while presenting low cost and minimal to no harm. The individuals in this study were instructed to avoid spending time outdoors, so natural light therapy did not interfere with the results. Ideally, this is the ultimate light therapy. Spending time in the sun is likely better than fluoxetine, and, when used with fluoxetine, may have added benefit in treating major depression no matter the season.