How to make differential diagnosis from depression to mania in adolescents?

Bipolar disorder (BP) is a familial and recurrent illness that significantly affects the child’s normal development. BP is often manifested by periods of depression during which the child has significant psychosocial problems and increased risk for suicide. Depression in youth is reported to be highly prevalent and relapsing condition that is treatable, but frequently comorbid and associated with significant morbidity and mortality, and has a high risk (20% to 40%) for switching into bipolar disorder. Studies in adults reported that bipolar depression was less recognized and treated than manic episodes despite the findings that depressive episodes and symptoms dominated the longitudinal course of BP and most suicide occurred during depression. Similar to adults, children with bipolar depression were more likely to have severe depression with suicidality, anhedonia, and hopelessness and had higher rates of comorbid disruptive behavior, anxiety, and substance use disorders, had lower Global Assessment of Functioning (GAF) scores and higher rates of hospitalization and psychiatric disorders in first-degree relatives compared to children with unipolar depression. However, most clinical studies with BP have focused on the manic phase of the illness. Depressed youth with BP are more likely to have more severe depression, greater suicidality, and higher rates of comorbidities and functional impairment relative to depressed youth with major depressive disorder (MDD or “unipolar depression”). However, it is difficult to clinically differentiate the symptoms of BP depression from those of MDD, and some children may still be in early phases of developing bipolar spectrum illness. This issue is very important because youth with BP depression may be treated with antidepressants that can precipitate an episode of mania or mixed BP symptoms. In addition, it may take up to 10 years from the initial symptoms of depression until BP is diagnosed and appropriate treatment is prescribed. Moreover, new DSM 5 introduced new “mixed features” specifier for major depressive disorder, first time identifying manic symptoms within depressive disorders spectrum. This brings the gap even more between mania and depression dichotomy. In conclusion, early differential diagnosis of depression and mania youth from a spectrum perspective is a key factor to enable youth to follow a normative developmental path and prevent an unrecoverable loss in their development.