Which mixed depression model? A comparison between DSM-5-defined mixed features and Koukopoulos' criteria

Area of Science:

• Psychiatry
• Mental Health Diagnostics
• Mood Disorders Research

Background:

• The Diagnostic and Statistical Manual of Mental Disorders 5th edition "with mixed features specifier" (DSM-5 MFS) criteria for mixed depression are debated due to their limited inclusion of typical manic symptoms.
• An alternative model of mixed depression (MxD) was developed by Koukopoulos, emphasizing the excitatory component.

Purpose of the Study:

• To compare the prevalence, clinical variables, and diagnostic capacity of DSM-5 MFS and Koukopoulos' MxD (KMxD) for identifying bipolar depression in patients with a major depressive episode (MDE).

Main Methods:

• 300 patients with MDE (155 major depressive disorder, 145 bipolar disorder) were recruited.
• Receiver operating characteristic (ROC) curves were used to assess the discriminative capacity of DSM-5 MFS and KMxD for bipolar disorder (BD).
• Logistic regression analyzed the association between clinical variables and the two diagnostic constructs.

Main Results:

• 165 patients met KMxD criteria, while 44 met DSM-5 MFS criteria.
• Both criteria showed overlapping discriminative capacity for BD (ROC AUCs: DSM-5 MFS 77.0%, KMxD 71.9%).
• KMxD demonstrated higher diagnostic sensitivity (78%) at its optimal threshold (≥3 symptoms) compared to DSM-5 MFS (77% at ≥1 symptom), with DSM-5 MFS showing significantly lower sensitivity (26%) at a threshold of ≥3 symptoms.

Conclusions:

• KMxD and DSM-5 MFS exhibit comparable discriminative capacity for bipolar depression.
• The current DSM-5 MFS threshold is less inclusive than KMxD.
• KMxD offers greater diagnostic sensitivity and a stronger association with clinical variables indicative of mixedness.