Can unipolar and bipolar pediatric major depression be differentiated from each other? A systematic review of cross-sectional studies examining differences in unipolar and bipolar depression

Introduction While pediatric mania and depression can be distinguished from each other, differentiating between unipolar major depressive disorder (unipolar MDD) and bipolar major depression (bipolar MDD) poses unique clinical and therapeutic challenges. Our aim was to examine the current body of knowledge on whether unipolar MDD and bipolar MDD in youth could be distinguished from one another in terms of clinical features and correlates. Methods A systematic literature search was conducted on studies assessing the clinical characteristics and correlates of unipolar MDD and bipolar MDD in youth. Results Four scientific papers that met our priori inclusion and exclusion criteria were identified. These papers reported that bipolar MDD is distinct from unipolar MDD in its higher levels of depression severity, associated impairment, psychiatric co-morbidity with oppositional defiant disorder, conduct disorder and anxiety disorders, and family history of mood and disruptive behavior disorders in first-degree relatives. Limitations Though we examined a sizeable and diverse sample, we were only able to identify four cross sectional informative studies in our review. Therefore, our conclusions should be viewed as preliminary. Conclusions These findings can aid clinicians in differentiating the two forms of MDD in youth.