Investigating neurobiological properties of bipolar prodrome

Purpose: Regarding the recently emerging "clinical high-risk" concept for mental disorders, Among different approaches to "high-risk" status, major depressive disorder (MDD) with mixed features (MF) was relatively less investigated in the child and adolescent psychiatry field. In addition to mixed features, this study aimed to investigate the neurocognitive features of youth with MDD. Method: Schedule for Affective Disorders and Schizophrenia for School-Age Children- Present and Lifetime Version, Childhood Depression Rating Scale-Revised, State-Trait Anxiety Inventory, Young Mania Rating Scale, Children's Global Assessment Scale were used for the general evaluation of the cases. Bipolar Prodrome Symptom Scale was also included in the study to investigate prodromal symptoms of cases. Stroop task and Trail Making Test was used for the evaluation of the neurocognitive features. Results: 127 youth (77 cases vs. 50 controls) were included in the current study. Case groups consisted of MDD with mixed features (MDD-MF) (clinical high risk, n=27) and MDD without mixed features (MDD-non-MF) (clinical low risk, n=50). Atypical features and psychotic features specifier more commonly coexisted in the MDD-MF group. Results also suggested the MDD-MF group had a higher prevalence of mood lability, oppositionality, and self-injurious behavior than MDD-non-MF counterparts. Also, while naming colors in the color-word card, the MDD-MF group made more cognitive mistakes than other study groups. Conclusion: Results of our study supported the notion that MDD-MF is a clinically distinct entity in adolescents. Related future studies are important to reveal the predictive role of inhibition deficits for the conversion to full bipolar disorders.