Improvement in depression scores after 1 hour of light therapy treatment in patients with seasonal affective disorder.
Study Goal
The researchers aimed to investigate the rapid effects of bright light therapy versus placebo dim red light on depressed mood in patients with seasonal affective disorder.
Results Summary
The study found a modest but statistically significant reduction in self-reported depression scores after a single session of bright light therapy compared to placebo. Improvements were observed on both the BDI-II (-1.3, p = 0.02) and POMS-D (-1.2, p = 0.02) scales.
Population
Patients with seasonal affective disorder (clinical sample of depressed individuals).
Effective Dosage
1 hour of bright light therapy and 1 hour of placebo dim red light.
Duration
Single session (1 hour per condition).
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
bright light therapy | decrease | self-report depression scores on the BDI-II | patients with seasonal affective disorder | -1.3 | significantly greater reduction | #1 |
bright light therapy | decrease | self-report depression scores on the POMS-D | patients with seasonal affective disorder | -1.2 | significantly greater reduction | #2 |
bright light therapy | increase | depressed mood | patients with seasonal affective disorder | - | significant but modest improvement | #3 |
light treatment | increase | depressed mood | clinical sample of depressed individuals | - | immediate improvement | #4 |
The purpose of this study was to investigate possible rapid effects of light therapy on depressed mood in patients with seasonal affective disorder. Participants received 1 hour of bright light therapy and 1 hour of placebo dim red light in a randomized order crossover design. Depressed mood was measured at baseline and after each hour of light treatment using two self-report depression scales (Profile of Mood States-Depression-Dejection [POMS-D] subscale and the Beck Depression Inventory II [BDI-II]). When light effects were grouped for the two sessions, there was significantly greater reduction in self-report depression scores by -1.3 (p = 0.02) on the BDI-II and -1.2 (p = 0.02) on the POMS-D. A significant but modest improvement was detected after a single active light session. This is the first study, to our knowledge, to document an immediate improvement with light treatment using a placebo-controlled design with a clinical sample of depressed individuals.