Non-randomised trial, 1993
Does light therapy reduce depression symptoms before the period?
All light treatments reduced depression, but the placebo treatment also worked, so we cannot tell if bright light is specifically helpful.
What they did
19 women with late luteal phase dysphoric disorder and 11 healthy women tried three types of daily light for 1 week during the premenstrual phase: bright white light in the morning, bright white light in the evening, or placebo dim red light in the evening. They rotated through all three treatments over 3 months.
What they found
All three light treatments, including the placebo dim red light, significantly reduced depressive ratings from baseline levels.
What it means for you
Light may help mood symptoms before the period, but the strong placebo effect makes it unclear whether bright light itself is beneficial. The sample was small.
19
women with LLPDD
2500
lux of bright light
1
week of treatment
About the study
- Original title
- Light therapy of late luteal phase dysphoric disorder: an extended study
- Authors
- Parry BL, Mahan AM, Mostofi N et al.
- Journal
- The American journal of psychiatry
- Year
- 1993
- Study design
- Non-randomised trial
- Participants
- 11
- What was tested
- Bright white light (2500+ lux) or placebo dim light (<10 lux) daily for 1 week during premenstrual phase
- Read the paper
- doi.org/10.1176/ajp.150.9.1417
Topics
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