Light Therapy

OBJECTIVE: Affective disorder during pregnancy is a common condition requiring careful judgment to treat the depression while minimizing risk to the fetus. Following up on promising pilot trials, we studied the efficacy of light therapy.

METHOD: Twenty-seven pregnant women with nonseasonal major depressive disorder according to DSM-IV (outpatients, university polyclinic) were randomly assigned to 7,000 lux fluorescent bright white or 70 lux dim red (placebo) light administered at home in the morning upon awakening for 1 h/d in a 5-week double-blind trial carried out between October 2004 and October 2008. Clinical state was monitored weekly with the 29-item Structured Interview Guide for the Hamilton Depression Rating Scale (HDRS) with Atypical Depression Supplement (SIGH-ADS). Changes of rating scale scores over time were analyzed with the general linear model. Differences from baseline of SIGH-ADS and 17-item HDRS scores at every time point were the dependent variables, time was the within-subjects factor, and treatment was the between-subjects factor. The model also included baseline score of depression and gestational age at intervention start.

RESULTS: The superiority of bright light over dim light placebo was shown for both SIGH-ADS (R² = 0.251; F(3,23) = 3.91; P<.05) and HDRS (R² = 0.338; F(3,23) = 5.42; P<.01) when analyzing the week-by-week change from baseline, and HDRS scores showed a significant interaction of treatment with time (F(4,92) = 2.91; P<.05). Categorical analysis revealed that the response rate (HDRS≥ 50% improvement) at week 5 was significantly greater for bright light (81.3%, n = 16) than for placebo light (45.5%, n = 11) (P<.05). Remission (final score≤ 8) was attained by 68.6% versus 36.4%, respectively (P<.05). Expectation ratings did not differ significantly between groups.

CONCLUSIONS: Bright white light treatment for 5 weeks improved depression during pregnancy significantly more than placebo dim red light. The study provides evidence that light therapy, a simple, cost-effective antidepressant modality with minimal side effects for the mother and no known risk for the unborn child, may be a useful nonpharmacologic approach in this difficult situation.

TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01043289.