The study addressed recent concerns regarding increasing prescription of antidepressant drugs to patients with no recorded psychiatric diagnosis. Records from ten large integrated health systems in the Mental Health Research Network were used to examine diagnoses received by 1,011,946 health plan members who filled at least one antidepressant prescription in 2010. Among individuals filling antidepressant prescriptions, psychiatric diagnoses recorded during the year were depressive disorders (48%), anxiety disorders (27%), bipolar disorders (3%), and attention deficit disorders (3%). The proportion of those filling prescriptions who had no psychiatric diagnosis was 39%, which fell to 27% after the analysis excluded prescriptions for antidepressants often prescribed for nonpsychiatric indications (tricyclic antidepressants, trazodone, and bupropion). Prescription of antidepressants to patients without an appropriate diagnosis appears to be less common than previously reported.