Substance-induced sleep disorders involve the use of, or exposure to, medications, toxins, alcohol or other drugs. Intoxication and withdrawal can also result in substance-induced sleep disorders. Recently, substance-induced sleep disorders and their importance in terms of best treatment practices for those with addictions is becoming more well recognized.

It has been shown that alcohol interferes with normal sleep patterns by disrupting particular neurotransmitters in the brain which control or regulate sleep. When these neurotransmitters are disrupted, disturbances can result. Small amounts of alcohol can cause early sedation or sleepiness, and is often used as a sedative. However, the use of alcohol as an effective sedative can be extremely misleading because the side effects that can result are usually even more harmful and detrimental to the natural sleep cycle. For instance, due to the natural elimination of alcohol from the body, arousal and sleep fragmentation can occur and the second half of the sleep period can be drastically interrupted. This is due to the fact that, although alcohol will cause sedation, it will also decrease REM sleep in the first half of the night resulting in the rebound of REM sleep later in the night. When the rebounding of REM sleep occurs, it causes frequent awaking during the night, and suppression of REM sleep. Gene rally, with continued consumption, alcohol's sedative effects decrease and its disruptive effects remain the same or increase. (NIAA-Alcohol Alert, 1998; Oscar-Berman, 1997; NIAA -NIH guide, 07/02/01)

Alcohol can be associated with sleep apnea. Sleep apnea is a disorder in which the upper air passage narrows or closes during sleep causing one to awake many times during the night gasping for air. Because of alcohol's depressant effects, the muscles of the upper air passage are affected, snoring is increased and sleep quality and total sleep time are reduced.

Cocaine is a stimulant that produces a sense of euphoria and is followed in several hours by a sense of depression. The euphoria produced by cocaine occurs because of the effect that cocaine has on the brain chemical dopamine. Since dopamine is also involved in wakefulness, the use of cocaine can have an effect on sleep patterns. It typically reduces nonREM sleep and REM sleep. When cocaine use is discontinued, sleepiness results causing one to use more cocaine to function. (Pacific Sleep, 07/13/01).

In a study by Weddington et al. (1990), cocaine withdrawal was examined over 28 days in male inpatients. In the discussion, the authors suggested that cocaine abstinence did not produce a "classic withdrawal pattern" as seen with other drugs of abuse. However, with respect to sleep, the results showed that cocaine-dependent patients reported more difficulty falling asleep and significantly more wakefulness than those who didn't use cocaine. Therefore, the cocaine withdrawal period can be initially associated with hypersomnia - excessive wakefulness.

Marijuana interferes with the normal sleep patterns. The active compound found in marijuana, delta-9-tetrahydrocannabinol or THC, interacts with specific chemicals in the brain that are associated with sleep and therefore, produces changes in brain wave patterns. The effects that can be contributed to this interaction depend on the amount of substance that is used. In small doses, REM sleep is only slightly suppressed, but large doses and/or continued use of marijuana can cause insomnia and significantly reduced REM sleep. (Pacific Sleep, 07/13/01).