Mood trajectories as a basis for personalized psychiatry in young people

Abstract In adolescents and young adults, depressive symptoms are highly prevalent and dynamic. For clinicians, it is difficult to determine whether a young person reporting depressive symptoms is at risk of developing ongoing mood difficulties, or whether symptoms form part of a transient maturational process. Hence, giving personalized treatment recommendations is a challenge in this group; current clinical practice guidelines promote a “watch and wait” approach, where generic and low-level treatments are offered first, while more intensive therapies, such as medication, are reserved for cases who do not benefit from first-line interventions. Trajectory analyses of longitudinally assessed symptoms in large cohorts have the potential to untangle clinical heterogeneity by determining subgroups or classes of symptom courses and their risk factors. Further, they explore the impact of known or suspected risk factors on a trajectory slope and intercept, and can trace the interrelation between depressive symptoms and other clinical outcomes over time. These studies suggest that young people fall into common mood trajectory classes, and that class membership and symptom course are mediated by biological and environmental risk factors. Studies also provide evidence that high and persistent depressive symptoms are associated with a range of concurrent health- and behavioral outcomes. These findings could assist in informing personalized and preventive strategies for clinical practice.