Bright light therapy and melatonin in motor restless behaviour in dementia: a placebo-controlled study

OBJECTIVE: The purpose of this study was to evaluate the effects of bright light therapy combined with melatonin on motor restless behaviour in dementia. DESIGN: Double-blind, placebo-controlled, cross-over trial consisting of four periods. One week wash-out was followed by a 2-week period of light therapy in combination with placebo or melatonin. The second wash-out period of 1 week was followed by 2 weeks of treatment (cross-over). SETTING: Twenty-four bed medium-stay psychogeriatric ward at a Dutch psychiatric teaching hospital. PATIENTS: Ten patients, who met the criteria for dementia (DSM-IV) and motor restless behaviour (subscale 10 of the GIP), were included. Informed consent was obtained by proxy. INTERVENTION: All subjects were exposed during 2x5 consecutive days for 30 minutes to 10,000 lux bright light and randomly administered 2.5 mg melatonin or placebo at 22.00 h. ASSESSMENTS: Clinical Global Impression (CGI), Dutch version of the geriatric behavioural observation scale (GIP), Social Dysfunction and Aggression Scale (SDAS) were assessed after each wash-out and treatment period. Outcome criteria were CGI, assessing motor restless behaviour, the SDAS, measuring extrovert aggression and the GIP, assessing social, psychomotor and emotional behaviour. RESULTS: Six demented inpatients completed the trial. Positive effects were found for the treatment combined with placebo. Patients were less restless and more co-operative. The condition with melatonin showed no additional positive effects, additionally, patients became more aggressive and showed the same or more disturbed behaviour. CONCLUSIONS: Bright light therapy has a positive effect on motor restless behaviour. Light therapy in combination with melatonin has no positive effects. The results might be explained by a possible overshoot of chronobiological synchronisation or the timing of the melatonin intake.