Previous research has indicated that around 5 per cent of pregnant women are clinically depressed, however, no drug therapy has been approved for use in pregnant women to date. Several small studies have indicated that light therapy may be successful in reducing levels of depression in this group.

Dr Dan Oren and colleagues from Yale University identified 16 pregnant women with major depression confirmed by DSM-IV criteria and a Structured Interview Guide for the Hamilton Depression Rating Score, Seasonal Affective Disorders Version (SIGH-SAD).

The women underwent an open trial of bright-light therapy after an initial two-week observation period. During the course of the trial (3-5 weeks), the women sat 33cm from a white fluorescent light source for one hour daily, starting within 10 minutes of awakening. After this time, patients were again observed for one week without light therapy.

Weekly evaluations of the women’s mental state using the SIGH-SAD ratings took place, and global seasonality scores were obtained throughout the three-week period. Birth outcome was also assessed.

The researchers found that the women’s depression scores improved by 49 per cent on average after three weeks, and the benefit continued in the seven patients who continued therapy for five weeks. No adverse effects were observed, and birth outcome did not appear to be influenced.

Writing in the American Journal of Psychiatry, the authors commented, “Our data did not yield any specific factors associated with response to light, although a number of patients without a history of recurrent winter depression clearly had excellent responses.

“A randomized controlled trial is warranted to ascertain that improvement is specific to bright-light exposure in antepartum depression.”

The study was first presented at the 11th annual meeting of the Society for Light Treatment and Biological Rhythms in Alexandria, Virginia, in May 1999.

Reference: Oren et al, American Journal of Psychiatry 2002;159:666-669

© Health Media Ltd 2002

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