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 towards 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.

Four hundred fifty-nine psychiatric patients in a depressive episode were interviewed by a trained diagnostic rater who administered semi-structured 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.

If the DSM-5 diagnostic threshold is lowered from 3 to 2 symptoms, then 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 prevalence more than doubled from 9.4% to 22.9% (n=105) going from the 2 and 3 symptom threshold, respectively. 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, history of suicide attempts or psychiatric hospitalization.

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.

None Declared