Objective
Evaluate over-prescribing of antidepressant medication for minimal or mild depression.
Method
Electronic records data from four large healthcare systems identified outpatients aged 18 or older starting a new episode of antidepressant treatment with an ICD9 diagnosis of depressive disorder (296.2, 296.3, 311, or 300.4). PHQ9 depression severity scores at time of treatment initiation were used to examine the distribution of baseline severity and the association between baseline severity and patients' demographic and clinical characteristics.
Results
Of 19,751 adults beginning treatment in 2011, baseline PHQ9 scores were available for 7051. In those with a baseline score, 85% reported moderate or severe symptoms (PHQ9 score 10 or more), 12% reported mild symptoms (PHQ score 5 to 9), and 3% reported minimal symptoms (PHQ9 score less than 5). The proportion reporting minimal or mild symptoms when starting treatment increased with age, ranging from 11% in those under age 30 to 26% in those aged 65 and older. The proportion with minimal or mild symptoms was also moderately higher among patients living in wealthier neighborhoods and those treated by psychiatrists. Nevertheless, across all subgroups defined by sex, race/ethnicity, prescriber specialty, and treatment history, the proportions with minimal or mild symptoms did not exceed 18%. Secondary analyses, including weighting and subgroup analyses, found no evidence that estimates of baseline severity were biased by missing PHQ9 scores.
Conclusions
In these health systems, prescribing of antidepressant medication for minimal or mild depression is much less common than suggested by previous reports. Given that this practice may sometimes be clinically appropriate, our findings indicate that over-prescribing of antidepressants for mild depression is not a significant public health concern.