The morbidity of sleep problems has been well documented; however, they are frequently associated with and are symptomatic of several psychiatric disorders. It is unclear how much of the morbidity can be accounted for by the associated psychiatric and substance abuse disorders and medical problems, and how much by the sleep problems per se. Sleep problems may also be an early sign of a psychiatric problem. This paper reports data from an epidemiologic community survey of over 10,000 adults living in three U.S. communities. A structured diagnostic assessment of psychiatric disorders as well as assessment of the presence of insomnia not due to medical conditions, medication, drug or alcohol abuse, and a 1-year follow-up were completed. Persons with insomnia in the past year without any psychiatric disorders ever (uncomplicated insomnia); with a psychiatric disorder in the past year (complicated insomnia); and with neither insomnia nor psychiatric disorders ever were compared on treatment utilization and the first onset of a psychiatric disorder in the subsequent year. Eight percent of those with uncomplicated as compared with 14.9% with complicated insomnia and 2.5% with neither had sought treatment from the general medical sector for emotional problems in the 6 months prior to the interview. The rates of treatment sought from the psychiatric specialty sector were 3.8%, 9.4%, and 1.2%, respectively. These differences were significant after controlling for sociodemographic characteristics and were sustained when the persons were interviewed 1 year later. Uncomplicated insomnia was also associated with an increase in risk for first onset of major depression, panic disorder, and alcohol abuse over the following year. Insomnia, even in the absence of psychiatric disorders, is associated with increased use of general medical and mental health treatment for emotional problems and for the subsequent first onset in the following year of some psychiatric disorders. Early diagnosis and treatment of uncomplicated insomnia may be useful.