Hypnosedatives are often used in geriatric care in Taiwan, though the chance of adverse effects of these drugs, such as cognitive impairment, falls, and even death, is higher and the consequences of the adverse effects are much more serious in the elderly than in young people. Hypnosedatives, however, remains in use due to the high prevalence of sleep and mood problems in the elderly population. With a rise in the number of reported cases in recent years, hypnosedative-induced complex sleep behaviors have received increased attention. Complex sleep behavior, when occurs, places the elderly at a higher risk of severe morbidity or mortality because of their functional decline and the changes in their sleep architecture and drug sensitivity. We accordingly conducted a review of the use of hypnosedatives in the elderly and the mechanism, risk factors, and management of possible complex sleep behaviors.