Association between poor tolerability of antidepressant treatment and brain functional activation in youth at risk for bipolar disorder

Objective: To investigate whether poor antidepressant tolerability is associated with functional brain changes in children and adolescents of parents with bipolar I disorder (at-risk youth). Methods: Seventy-three at-risk youth (ages 9-20 years old) who participated in a prospective study and had an available baseline functional magnetic resonance imaging (fMRI) scan were included. Research records were reviewed for the incidence of adverse reactions related to antidepressant exposure during follow-up. The sample was divided among at-risk youth without antidepressant exposure (n=21), at-risk youth with antidepressant exposure and no adverse reaction (n=12), at-risk youth with antidepressant-related adverse reaction (n=21), and healthy controls (n=20). The fMRI task was a continuous performance test with emotional distracters. Region-of-interest mean activation in brain areas of the fronto-limbic emotional circuit was compared among groups. Results: Right amygdala activation in response to emotional distracters significantly differed among groups (F3,66 = 3.1, p = 0.03). At-risk youth with an antidepressant-related adverse reaction had the lowest amygdala activation, while at-risk youth without antidepressant exposure had the highest activation (p = 0.004). Conclusions: Decreased right amygdala activation in response to emotional distracters is associated with experiencing an antidepressant-related adverse reaction in at-risk youth. Further studies to determine whether amygdala activation is a useful biomarker for antidepressant-related adverse events are needed.

Medication exposure and predictors of first mood episode in offspring of parents with bipolar disorder: a prospective study

Objectives: To prospectively investigate whether baseline clinical characteristics and medication exposure predict development of major depressive disorder or bipolar disorder in offspring of parents with bipolar disorder. Methods: Youth aged 9-20 years with at least one biological parent with bipolar disorder and no prior history of mood or psychotic episodes (n=93) were prospectively evaluated and treated naturalistically during the study. Participants were divided into two groups: converters, defined as those who met DSM-IV criteria for a mood episode during follow-up (n=19); or non-converters (n=74). Logistic regression models were used to investigate associations between baseline clinical variables and medication exposure during follow-up and risk of developing a first mood episode (conversion). Results: Multivariate regression analyses showed that baseline anxiety disorders and subsyndromal mood disorders were associated with increased risk of conversion during follow-up. Adding medication exposure to the multivariate model showed that exposure to antidepressants during follow-up was associated with increased risk of conversion. Conclusions: Caution should be used when treating bipolar offspring with anxiety and/or emerging depressive symptoms using antidepressant agents, given the increased risk of developing a major mood disorder.