Understanding the natural landscape of the chronology of major depressive disorder and mania in youth

Introduction Major Depressive Disorder (MDD) and Bipolar Disorder (BPD) are debilitating disorders increasingly prevalent in pediatric populations. MDD and BPD often share depressive symptoms, making them difficult to distinguish. Despite these similarities, treatment courses differ vastly, and incorrect prescriptions can worsen the clinical course. Thus, accurate diagnosis is critical. Further complicating diagnosis is that BPD may initially present with depression, mania, or both. However, there is limited literature examining the course of disorder development. This was a naturalistic cohort study aiming to identify the main patterns of symptoms and relationship to MDD versus BPD development over time. Methods A cross-sectional assessment of psychiatric interviews (K-SADS-E) was reviewed from 2,947 consecutive referrals of patients aged 3 to 17 to a pediatric psychopharmacology program (1991–2008). Results 46% (n=1357) of the sample met criteria for depression and/or mania. Among them, 60% (n=818) had only MDD, 7% (n=101) only mania, and 33% (n=428) had both. Of the comorbid group, 29% (n=126) developed depression before mania, 39% (n=172) developed both concurrently, and 32% (n=140) had mania before depression. Average age of onset was 5.9 ± 4.4 years for mania and 7.4 ± 4.2 years for depression. Discussion The results highlight irregularity in the trajectory of depression and mania in youth. Without biomarkers, clinical acumen is necessary to distinguish between the two. Given the high consequences of misdiagnosis, including manic switch, great care must be taken in prescribing. By illustrating the chronology of mood symptoms, we aim to support clinicians in the diagnostic process.