The US National Library of Medicine National Institutes of Health report, Effects of Drugs on Sleep, states that: “Chronic use or abuse of certain drugs may lead to the development of substance-related sleep disorders. Primary sleep disorders, such as apnea, periodic movement disorders, and parasomnias, may be exacerbated by various drugs.”
According to a Harvard Report on how External Factors Influence Sleep, the impact of prescription medications on sleep varies from one type to the next. For instance, beta blockers, which are commonly used to reduce blood pressure, cause decreased slow-wave sleep and in important REM sleep, while increasing sleepiness during the daytime hours. Alpha blockers, also used to reduce blood pressure and to treat some prostate conditions, also lead to decreases in REM sleep as well as boosts to daytime sleepiness. Some antidepressants, known as SSRIs, are believed to actually promote insomnia. The long-term impact of other antidepressant drugs on sleep are, as of yet, unknown.