Bright Light Treatment Has Limited Effect in Subjects over 55 Years with Mild Early Morning Awakening

Abstract

31 subjects, age 55 yr. or older, suffering from mild early morning awakening were randomized to either a bright light (10,000 lux) or to a red dim light placebo condition (200 lux). Light exposure took place in the evening in the patients' homes, 60 to 30 min. before bedtime and lasted for 3 wk. The subjects kept a sleep diary for 2 wk. and wore an actigraph for 1 wk. both before treatment and at post-treatment. Of the eight sleep diary outcome variables, significant effects that could be attributed to the light treatment were only detected for time spent in bed after final morning awakening. None of the six actigraph outcome variables yielded any significant effect of the light therapy. Explanations for the limited therapeutic effects of bright light treatment obtained in the present study are discussed, such as the criteria defining early morning awakening, the selection procedure, problems with compliance, age of the sample, and the dose of light. The lack of an objective circadian marker in this study could represent a problem concerning the timing of the light exposure. Despite the limited success of bright light therapy in this study, bright light therapy should still be considered as a treatment option for early morning awakening.