Alzheimer’s disease (AD), the most common cause of dementia, is associated with sleep disturbances among 25% to 35% of individuals with the illness.1 Sleep disorders in AD result in significant caregiver distress, increased health care costs and increased rates of institutionalization.2,3
AD related sleep complaints include sleep fragmentation, increased sleep latency (time taken to go to sleep), nocturnal wandering and increased daytime sleepiness.4 Many patients with AD also experience ‘sun downing’, which is confusion and agitation in the late afternoon and evening which decreases during daylight hours.5
Sleep disturbances in AD are due to multiple factors including physiologic changes related to the degenerative brain disease, physiological changes related to normal aging, primary sleep disorders(e.g. Sleep apnea, restless legs syndrome), comorbid medical and psychiatric conditions and environmental and behavioral factors (e.g. poor “sleep hygiene.”).6
Medications may also adversely affect sleep. Cognitive enhancers like donepezil, an acetylcholinesterase inhibitor, can cause nighttime agitation and nightmares.1 Atypical antipsychotics (e.g. olanzapine or risperidone) can increase daytime fatigue and somnolence.7 Anxiolytics and antidepressants can cause daytime sleepiness and increased risk for falls in older adults.8
A variety of medications are used in the management of sleep disorders in AD including atypical antipsychotics, benzodiazepines, non-benzodiazepine hypnotics (e.g. zolpidem, zopiclone, and zaleplon), melatonin, sedating antidepressants and antihistamines.9,10 However, to date, there is limited research on the safety and efficacy of these medications in patients with AD.
A meta-analysis by McCleery, et al reported that there were no random controlled trials of most of the medications used to treat sleep disorders in AD including benzodiazepine and non-benzodiazepine hypnotics.4 They found no evidence that melatonin or ramelton had beneficial effects on sleep disorders in moderate to severe AD. A small randomized, control trials of patients with AD treated with trazodone reported significantly longer nocturnal total sleep time and greater sleep efficiency.11