Differential Reduction in Symptoms of Late Luteal Phase Dysphoric Disorder as a Function of Light Therapy

The effect of bright white morning light, bright white evening light, and dim red evening light therapy on specific types of symptoms associated with late luteal phase dysphoric disorder (LLPDD) was examined using the Hamilton Rating Scale for Depression, the Beck Depression Inventory, and a questionnaire assessing atypical depressive symptoms. Fourteen women were assigned to a randomized, crossover trial involving light administered during the late luteal phase of the menstrual cycle across 3 intervention months. A reduction of some but not all LLPDD symptoms was observed following light exposure as a function of light intensity and time of exposure. Specifically, general depressive symptoms [as measured by self-report (Beck Depression Inventory) and semistructured interview (Hamilton Rating Scale for Depression)] as well as atypical, seasonal-type symptom ratings of LLPDD decreased after bright white morning, bright white evening, and dim red evening light treatments. Melancholic symptoms of LLPDD declined after bright morning and bright evening light treatments, but no effect of dim evening light on these symptoms was observed. A trend for the reduction of somatic symptoms in LLPDD was observed following bright morning light treatment, but no significant effect of light treatment on anxiety symptoms was found. Results are discussed in terms of a placebo response to intervention, the relationship of LLPDD to other psychiatric disorders, and implications for future research of LLPDD.