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Extraocular light therapy in winter depression: a double-blind placebo-controlled study.
K M Koorengevel1, M C Gordijn, D G Beersma
1Department of Psychiatry, Groningen, The Netherlands.
Biological Psychiatry
|November 13, 2001
Summary
Extraocular light therapy did not show benefits beyond placebo for seasonal affective disorder (SAD). This treatment did not alter the circadian pacemaker or melatonin onset in SAD patients.
Area of Science:
- Chronobiology
- Psychiatry
- Sleep Medicine
Background:
- Seasonal affective disorder (SAD) is hypothesized to involve a phase-delayed circadian pacemaker.
- Morning light therapy is effective for SAD, potentially by advancing circadian phase.
- Extraocular light has shown potential for circadian phase-shifting.
Purpose of the Study:
- To investigate the efficacy of extraocular light therapy in treating SAD.
- To determine if extraocular light can induce phase-shifts in the human circadian pacemaker.
- To compare extraocular light therapy with a placebo in SAD patients.
Main Methods:
- A double-blind, placebo-controlled study involving 29 SAD patients.
- Extraocular light or placebo administered to the popliteal fossae from 8 AM to 11 AM.
- Clinical state, mood, alertness, sleep, and dim light melatonin onset (DLMO) were assessed.
Main Results:
- Both extraocular light and placebo groups showed progressive clinical improvement.
- No significant differences were found between groups in clinical scores or self-ratings.
- No significant differences in DLMO timing were observed before or after treatment.
Conclusions:
- Extraocular light therapy's response in SAD patients was not superior to placebo.
- Extraocular light did not demonstrate a phase-shifting effect on the circadian pacemaker.
- The findings suggest extraocular light is not an effective treatment for SAD.