Bright Light plus Melatonin in Elderly Patients with Dementia

An inexpensive combination treatment has modest positive effects.

Many patients with dementia have disturbed sleep–wake cycles along with deteriorating cognition, mood, and behavioral organization. These researchers investigated the effects of bright light and melatonin, two major synchronizers of the circadian pacemaker, in 189 residents of 12 Dutch assisted-care facilities.

Facilities were randomized to provide daytime bright (1000 lux) or dim (300 lux) light, and residents (mean age, 86; 87% diagnosed with dementia; 90% women) were randomized to receive melatonin (2.5 mg/day) or placebo for a maximum of 3.5 years (mean, 15 months). Mixed-effects regression analyses allowed investigators to account for the substantial amount of missing data, both within subjects and from drop-outs due to death, transfer, or the discontinued participation of some facilities.

Compared with double placebo, bright light reduced cognitive decline by 5%, depressive symptoms by 19%, and physical functional decline by 53%. Melatonin reduced sleep latency by 19%; also, it increased sleep duration by 6% and duration of uninterrupted sleep by 25%. Melatonin alone tended to aggravate behavioral withdrawal and depression; its effects on restlessness and nocturnal awakenings emerged slowly. The combination of light and melatonin increased sleep efficiency by 3.5%; also, the combination reduced nocturnal restlessness by 9%, duration of individual nocturnal awakenings by 12%, and agitated behavior by 9%.

Comment: In this unique study, a simple environmental intervention had modest and beneficial effects on cognition, mood, and physical function in elderly group-home residents. Combining melatonin with bright light improved sleep and attenuated nocturnal arousal. Most improvements were comparable in size to what would be expected for a marketed medication. As the authors note, even the cognitive effects (which were more modest than the physical ones) fell in the range of those reported for cholinesterase inhibitors. Light plus melatonin could improve quality of life in this highly vulnerable population at a modest cost.

Peter Roy-Byrne, MD, Published in Journal Watch Psychiatry.

Riemersma-van der Lek RF et al. Effect of bright light and melatonin on cognitive and noncognitive function in elderly residents of group care facilities: A randomized controlled trial. JAMA 2008 Jun 11; 299:2642.


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