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No. In this study of 459 depressed patients, the authors concluded that the results did not support lowering the DSM-5-TR diagnostic threshold for the mixed features specifier from 3 criteria to 2. Lowering the threshold sharply increased prevalence, but patients with exactly 2 mixed features did not show the pattern of bipolar-spectrum and clinical validators that would justify treating them as equivalent to patients meeting the current 3-symptom threshold.

Lowering the threshold from 3 symptoms to 2 substantially increased how many depressed patients were classified as having mixed features. Using the DSM-5-TR majority-of-episode time frame, prevalence rose from 3.9% (n=18) to 13.1% (n=60). Using a past-week time frame, prevalence rose from 9.4% (n=43) to 22.9% (n=105).

Yes, but the strength of that association depended on the symptom threshold used. At the DSM-5-TR threshold of 3 or more mixed features, patients with bipolar disorder were significantly more likely than patients with major depressive disorder to meet criteria (29.8% vs 9.2%; OR 4.18, 95% CI 2.06-8.48). When the threshold was lowered to 2 or more features, bipolar disorder was still more likely than major depressive disorder to be classified as mixed (48.9% vs 24.8%; OR 2.91, 95% CI 1.58-5.38), but when the analysis was limited to patients with exactly 2 features, the difference was no longer significant (19.1% vs 15.5%; OR 1.29, 95% CI 0.59-2.79).

No. Among patients with major depressive disorder, those with exactly 2 mixed features did not differ from patients with 0 or 1 mixed feature on family history of bipolar disorder, psychosocial functioning, age of onset, history of psychiatric hospitalization, or lifetime suicide attempts. The authors interpreted this as evidence that 2 symptoms alone did not identify the subgroup with the validators expected for mixed depression.

The main difference was greater current symptom severity. Compared with patients without mixed features, patients with exactly 2 mixed features had greater symptom severity, although the difference on the 17-item Hamilton Depression Rating Scale was not significant. They did not differ from patients with 0 or 1 mixed feature in level of suicidal ideation during the week before evaluation, functioning, age of onset, psychiatric hospitalization, family history of bipolar disorder, or frequency of comorbid disorders.

Patients with exactly 2 mixed features appeared less clinically burdened on several validators than patients with 3 or more mixed features. Compared with the full-threshold group, the 2-feature group had significantly lower rates of social anxiety disorder, borderline personality disorder, and attention deficit disorder, and they were significantly less likely to have a lifetime history of attempted suicide. They did not differ from the 3-or-more-feature group on functioning, age of onset, psychiatric hospitalization, or family history of bipolar disorder.

Yes. The study found that time frame materially changed case identification. Using the current 3-symptom threshold, only 3.9% (n=18) met criteria when symptoms had to be present for the majority of the depressive episode, whereas 9.4% (n=43) met criteria when symptoms were assessed over the past week.

The study evaluated 459 patients with current DSM-IV/DSM-5-TR major depressive disorder or bipolar disorder in a current depressive episode who were presenting for intake at a Rhode Island partial hospital program. Investigators compared 3 groups: patients with 0-1 DSM-5-TR mixed features, exactly 2 mixed features, and 3 or more mixed features. The DSM-5 Mixed Features Specifier Interview assessed the 7 DSM-5 criteria, and the analysis asked whether patients with exactly 2 features resembled the 3-or-more-feature group rather than the 0-1-feature group on established validators such as bipolar diagnosis, family history, comorbidity, severity, suicidality, hospitalization, age of onset, and functioning.

The authors noted several important limitations. The study was conducted in a single clinical program, and most participants were white, female, and insured, so replication in more diverse and community-based samples is needed. The same rater completed the mixed-features interview and the clinician severity scales, and the relatively small number of patients with major depressive disorder who met full DSM-5-TR mixed features criteria may have limited power to detect some differences from the 2-feature group.