How Many Criteria Should Be Required to Define the DSM-5 Mixed Features Specifier in Depressed Patients?

Background: During the past 2 decades, there has been intense interest in the clinical significance of the concurrence of manic symptoms in depressed patients. DSM-5 introduced a mixed features specifier for both bipolar depression and major depressive disorder. Studies of the DSM-5 mixed features specifier have generally found a low prevalence of mixed depression. One approach toward increasing the sensitivity of the DSM-5 mixed features criteria is to lower the classification threshold. In the present study, we examine the impact of lowering the DSM-5 diagnostic threshold from 3 to 2 criteria on the prevalence and validity of the DSM-5 mixed features specifier for depression. Methods: Four hundred fifty-nine psychiatric patients in a depressive episode were interviewed by a trained diagnostic rater who administered semistructured interviews including the DSM-5 Mixed Features Specifier Interview. The patients were rated on clinician rating scales of depression, anxiety, and irritability and measures of psychosocial functioning, suicidality, and family history of bipolar disorder. Results: When the DSM-5 diagnostic threshold was lowered from 3 to 2 symptoms, the prevalence of mixed features based on the DSM-5 majority of episode time frame tripled from 3.9% to 13.1% (n=60). Based on a past week time frame, the prevalence of mixed features more than doubled from 9.4% to 22.9% (n=105) upon lowering the threshold from 3 to 2 criteria. However, there was no difference between the patients with 2 mixed features and patients with 0 or 1 mixed features on family history of bipolar disorder, psychosocial impairment, presence of comorbid disorders, age of onset, or history of suicide attempts or psychiatric hospitalization. Conclusions: The results of the present study do not support lowering the DSM-5-TR diagnostic threshold for the mixed features specifier in depressed patients from 3 to 2 criteria.