Depression during pregnancy is common and has major health implications for the mother, the fetus and the family. On this website, we have reviewed numerous treatments for affective disorders in pregnancy, including psychotropic medications and several forms of psychotherapy. We have not had much data to support the use of light therapy for antepartum depression, yet I often discuss light therapy as a potential adjunctive treatment for patients with a seasonal component to their depression. A recent study, published by Wirz-Justice and colleagues in the Journal of Clinical Psychiatry, provides evidence that light therapy may be a useful non-pharmacologic treatment for women who suffer from depression during pregnancy(1).
The authors of this study first review how light therapy is a well-established treatment for seasonal affective disorder and has shown some potential as treatment for nonseasonal major depression (2-6). They also review two pilot studies of light therapy in antepartum depression which provided the rationale for their study.
- In an open trial administering 3-5 weeks of light therapy (10,000 lux for 60 minutes daily shortly after subjects awakened), mean depression ratings improved by 50% (7).
- In a 5 week randomized, controlled trial of light therapy 7,000 lux and 500 lux (designated as the placebo) for 60 minutes daily, found improvements in depression ratings of 60% and 41%, respectively (8).
The authors hypothesized that morning bright light therapy (7,000 lux white) would be an effective treatment for major depression during pregnancy compared with low-intensity placebo light therapy (70 lux red or dim light) when administered for 60 minutes daily for 5 weeks. This randomized, double-blind, placebo-controlled clinical trial was conducted in Switzerland and recruited from both university outpatient psychiatry and obstetric clinics. A total of 100 women were screened via telephone interview and 70 met criteria by scoring > 10 on the Edinburgh Postnatal Depression Scale (EPDS). A diagnosis of major depressive disorder was confirmed using the Structured Clinical Interview for DSM-IV.
Women were included if they were 18-45 years of age, between 4 and 32 weeks of gestation, medically healthy, with normal ocular function. All women had a score of > 20 on the Hamilton Depression Rating Scale (HDRS). Four women who had taken an antidepressant for more than 3 months without improvement were included in the study.
Women were excluded if they had diagnoses of bipolar I or II disorder, seasonal affective disorder, any psychotic episode, substance abuse within the last 6 months, primary anxiety disorder, recent history of suicide attempt (6 months), delayed sleep phase disorder or hypersomnia.
Subjects were asked to maintain their habitual bedtime and wake-up times. Light treatment was scheduled to commence within 10 minutes of wake-up time. The light box (Healthlight, SphereOnce Inc, Silver Plum, Colorado) provided either an active dose (7,000 lux white light) or the placebo dose (70 lux red) for one hour each day. Women in both groups had similar sociodemographic and clinical variables (including number of previous depressive episodes, duration of present depressive episode and age at first onset of depression). Of the 70 women eligible after screening, 46 women were enrolled in the study. Of the 46, 24 were randomized to bright light and 22 to dim light. 34 women completed the trial (12 dropouts). An additional 6 women were excluded from analysis because they began adjunctive antidepressant treatment during the course of the study.
The results showed that bright-light therapy showed greater reduction in depression ratings compared to placebo dim light after 5 weeks. Response (defined as HDRS 50% reduction in HDRS) at week 5 was significantly greater for bright light (81.3%) than for placebo light (45.5%) (p < .05). Remission (HDRS < 8 ) was attained by 68.6% in the light group versus 36.4% in the placebo group (p < .05). The four subjects taking antidepressants (with no response at entry into the study) were in the bright light group, and all improved. In this study, there were no switches into hypomania, a potential risk for patients with undiagnosed bipolar disorder.
The authors suggest that the benefits of light therapy are promising for pregnant women with depression and the side effect profile is also very good. The authors do point out that there are no studies assessing the risk of light therapy to the fetus; however, they reason that because one hour of light therapy provides light exposure similar to one hour of outdoor daylight, this treatment should not pose any risk to the fetus. They further point out that in patients with winter depression, a regular 1-hour morning walk outdoors provides therapeutic effects similar to a light box (9). The authors point out those patients with retinal or other eye disorders should consult with an ophthalmologist prior to using light therapy.
While light therapy may not be a replacement for antidepressant medications for all pregnant women with depression, light therapy could play an important role in the treatment of certain subgroups of women. Because patients with more severe depression (i.e., those with suicidal ideation and/or psychotic symptoms) were excluded, it is unclear if light therapy would be effective in this population. Similarly it is not known if light therapy would be as effective for women with comorbid anxiety disorders.
This treatment option would need to be discussed with the woman’s mental health provider, as well as her obstetrician, and care should be taken to only use a light box that has been clinically demonstrated to provide an effective dose of bright light. This study reminds us of the importance of natural light, as well as exercise which are both free and carry no significant risk.
April Hirschberg, MD
- Wirz-Justice A, Bader A, Frisch U, et al. A Randomized, Double-Blind, Placebo-Controlled Study of Light Therapy for Antepartum Depression. J Clin Psychiatry 2011;72(7):986-993.
- Wirz-Justice A, Benedetti F, Terman M. Chronotherapeutics for Affective Disorders. A Clinician’s Manual for Light and Wake Therapy. Bael, Switzerland: S. Karger AG; 2009.
- Kripke DF. Light treatment for nonseasonal depression: speed, efficacy, and combined treatment. J Affect Disord. 1998;49(2):109-117.
- Tuunainen A, Kripke DF, Endo T. Light therapy for non-seasonal depression. Cochrane Database Syst Rev. 2004;(2):CD004050.
- Golden RN, Gaynes BN, Ekstrom Rd, et al. The Efficacy of light treatment therapy in the treatment of mood disorders: a review and meta-analysis of the evidence. Am J Psychiatry. 2005;162(4):656-662.
- EvenC, Schroder CM, Friedman S, et al. Efficacy of light therapy in nonseasonal depression: a systematic review. J Affect Disord. 2008;108(1-2):11-23.
- Oren DA, Wisner KL, Spinelli M, et al. An open trial of morning light therapy for treatment of antepartum depression. Am J Psychiatry. 2002;159(4):666-669.
- Epperson CN, Terman M, Terman JS. Et al. Randomized clinical trial of bright light therapy for antepartum depression, preliminary findings. J Clin Psychiatry. 2004; 65(3):421-425.
- Wirz-Justice A, Graw P, Krauchi K, et al. ‘Natural’ light treatment of seasonal affective disorder. J Affect Disord. 1996; 37(2-3):109-120.