National Trends in Psychiatric Not Otherwise Specified (NOS) Diagnosis and Medication Use Among Adults in Outpatient Treatment.

OBJECTIVE: This study examined national trends between 1999 and 2010 in not otherwise specified (NOS) DSM-IV psychiatric diagnoses and in related medication treatment patterns reported for adults during outpatient physician office visits.

METHODS: Data on physician office visits by adults (ages 18-64) with a psychiatric diagnosis were from the National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey (1999-2010) (N=52,026). Trends for visits with full-criteria diagnoses compared with visits with NOS diagnoses were analyzed for major psychiatric diagnostic groups, physician specialty, and prescribed medications. Population weighted chi square and logistic regression analyses were utilized.

RESULTS: Between 1999-2002 and 2007-2010, the proportion of all mental health visits by adults to office-based physicians that involved an NOS diagnosis increased significantly, from 42% to 50% (p<.001). Significant proportional increases in NOS diagnoses included bipolar disorders NOS (5% to 55%), anxiety disorders NOS (50% to 62%), and mood disorders NOS (.4% to 1.8%). In 2007-2010, NOS visits accounted for a greater proportion of visits to nonpsychiatrists than to psychiatrists (61% and 35%, respectively). Psychotropic medications prescribed during visits increased over time for both full-criteria and NOS diagnoses, but the increase was greater for NOS visits, specifically for antipsychotics, anticonvulsants-mood stabilizers, and lithium. By 2007-2010, psychotropic monotherapy and multidrug regimens were comparable for full-criteria and NOS diagnoses.

CONCLUSIONS: The proportion of U.S. physician visits with an NOS psychiatric diagnosis increased to nearly 50% in 2007-2010. The increase raises concerns about the precision of psychiatric diagnoses in community care and about the impact on concomitant medication regimens.