Study objectives: This investigation tabulates the most common diagnostic codes associated with use of hypnotic medications during physician-patient encounters in the U.S.
Design: Estimates were derived from the National Ambulatory Medical Care Survey (NAMCS) from 1990 through 1998. Diagnoses were coded according to the International Classification of Disease-Clinical Modification-9th Edition (ICD-9-CM).
Setting: The NAMCS collects outpatient visit data from nonfederal physicians of all specialties, except anesthesiology, pathology, and radiology.
Measurements and results: Hypnotic medications were more commonly associated with psychiatric codes than with the symptom of insomnia. Primary insomnia did not appear among the codes most commonly associated with a hypnotic prescription.
Conclusions: Hypnotics were more commonly associated with psychiatric codes than with insomnia codes, but it is unknown whether the coding accurately reflects the true diagnoses. Still, since there is minimal data on the efficacy and safety of hypnotics in persons with psychiatric disorders, these findings may signal a critical knowledge gap in the treatment of insomnia.