Effectiveness of a sleep disorders center: a 9-month follow-up.

To assess the usefulness of a sleep disorders center the authors sent follow-up questionnaires to patients and referring physicians 9 months after each diagnostic evaluation. Findings suggest that sleep disorders centers provide a useful diagnostic service, especially for patients suffering from excessive daytime sleepiness. This problem usually has a medical etiology, and sleep laboratory evaluations seemed crucial for about two-thirds of all such patients. Insomnia was more likely to involve behavioral/psychological factors; about 30% of the patients with long-term, serious insomnia seemed to benefit markedly from the sleep center evaluation.