Bright light helps non-seasonal major depression in the elderly

More evidence for the profound effects of light therapy is offered in a randomized placebo-controlled trial published recently in the Archives of General Psychiatry that documents the effectiveness of bright light therapy for relieving depression. The authors first observe:

"Major depressive disorder (MDD) in elderly individuals is prevalent and debilitating. It is accompanied by circadian rhythm disturbances associated with impaired functioning of the suprachiasmatic nucleus, the biological clock of the brain. Circadian rhythm disturbances are common in the elderly. Suprachiasmatic nucleus stimulation using bright light treatment (BLT) may, therefore, improve mood, sleep, and hormonal rhythms in elderly patients with MDD."

They went about testing their assumption with a double-blind, placebo-controlled randomized clinical trial of bright light treatment (BLT) with 89 subjects age 60 or above living in the Amsterdam region who suffered from MDD. Treatment consisted of three weeks of 1-hour early-morning BLT (pale blue, approximately 7500 lux) vs placebo (dim red light, approximately 50 lux). They were assessed for the degree of depression at baseline (T0), after 3 weeks of treatment (T1), and 3 weeks after the end of treatment (T2) with the Hamilton Scale for Depression and cortisol and melatonin levels. As for the results:

"Intention-to-treat analysis showed Hamilton Scale for Depression scores to improve with BLT more than placebo from T0 to T1 (7%) and from T0 to T2 (21%). At T1 relative to T0, get-up time after final awakening in the BLT group advanced by 7%, sleep efficiency increased by 2%, and the steepness of the rise in evening melatonin levels increased by 81% compared with the placebo group. At T2 relative to T0, get-up time was still advanced by 3% and the 24-hour urinary free cortisol level was 37% lower compared with the placebo group. The evening salivary cortisol level had decreased by 34% in the BLT group compared with an increase of 7% in the placebo group."

Remember, this is not seasonal affective disorder (SAD) but non-seasonal major depression. It's also noteworthy that beneficial effects could still be measured three weeks after the end of treatment. The authors conclude:

"In elderly patients with MDD, BLT improved mood, enhanced sleep efficiency, and increased the upslope melatonin level gradient. In addition, BLT produced continuing improvement in mood and an attenuation of cortisol hyperexcretion after discontinuation of treatment."