Mechanism of Antidepressant-Related Dysfunctional Arousal in High-Risk Youth

The primary goals of this proposal are to investigate the etiological mechanisms associated with antidepressant-related dysfunctional emotional arousal and to characterize baseline neurobiological risk factors that predict the development of dysfunctional emotional arousal in treatment seeking youth with a family history of BD. Antidepressants have moderate benefit for treating mood and anxiety disorders in childhood but their effects on the developing brain are largely unknown. Antidepressants are among the most commonly prescribed medications used by youth in the United States and are used to treat many psychiatric disorders including depression, dysthymia and anxiety. However, recent reviews suggest that antidepressants provide only mild to moderate benefit. Moreover, a growing number of case reports and clinical studies have described antidepressant-related psychiatric adverse events such as aggression, psychosis, agitation, suicidal ideation, hypomania or mania, all behaviors associated with increased emotional arousal. Importantly, these adverse events are more likely to occur in children than adults. With younger ages of treatment combined with increased and repeated exposure during critical sensitive periods of neurodevelopment, these adverse events are becoming a rising concern for youth, and may lead to the development of serious psychopathologies in youth that carry an enormous burden of illness, such as bipolar disorder (BD). Given that BD typically begins before 18 years of age and with a depressive episode, there are millions of youth in the U.S. each year who experience their first bipolar episode as a depressive episode that is routinely treated with antidepressants. However, the mechanisms and risk factors through which antidepressants increase risk for developing adverse outcomes are largely unknown. Youth with a family history of BD have a high likelihood of developing adverse responses to antidepressants, possibly because such youth are already vulnerable to developing dysfunctional emotional arousal and may use antidepressants to treat mood and anxiety symptoms. Indeed, a family history of BD is among the strongest risk factors for developing disorders of emotional arousal in youth. Twin and family studies have provided compelling evidence that having a parent with BD is associated with dramatic increases in risk for the offspring's development of disorders of emotional arousal compared with the general population. Moreover, when these offspring develop dysfunctional emotional arousal, their risk of developing BD increases even further. Antidepressants are commonly used to treat initial mood presentations; however, they may also accelerate the onset of dysfunctional emotional arousal in these high-risk youth. In this context, it becomes difficult to disentangle a natural illness progression from an antidepressant-related dysfunction leading to BD. Thus, there is a significant clinical dilemma regarding whether antidepressants should be prescribed to treat youth with a family history of BD, who also have DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) depressive and anxiety disorders.