Virtually all psychiatric and substance use disorders are associated with sleep disruption. Studies indicate that psychiatric disorders are related closely to chronic insomnia and that psychoactive substances have acute and chronic effects on sleep architecture. Several aspects of sleep are compromised in individuals taking these substances, ranging from difficulty initiating sleep to difficulty maintaining sleep and hypersomnia. Sleep disturbances are apparent in person taking psychoactive drugs or alcohol and have been found to persist long after withdrawing from these drugs. For some, sleep disturbance can be so severe as to reverse treatment success and precipitate relapse to addiction or dependence. There is increasing evidence that primary insomnia without a concurrent psychiatric disorder is a risk factor for later developing substance use disorders. Patients were asked to complete two brief screening tools, the Michigan Alcohol Screening Test and Drug Abuse Screening Test, to examine substance use patterns among patients referred for a variety of sleep complaints in a sleep disorders clinic. We found that patients who demonstrated a variety of sleep complaints were more likely to have alcohol and drug problems than those in the general populations.