A functional magnetic resonance imaging investigation of uncertainty in adolescents with anxiety disorders.

Background: Pediatric anxiety disorders, although highly prevalent, are understudied with little known about their pathophysiology. Intolerance of uncertainty (IU) is a trait associated with worry, a key characteristic of these disorders. Neural responses to uncertainty in healthy subjects involve the same frontal-limbic circuits that are hyper-responsive in pediatric anxiety. As such, the present study examines the relationship between IU and neural responses to uncertainty in anxious adolescents.

Methods: Sixteen adolescents (ages 13-17) diagnosed with generalized anxiety disorder and/or social phobia (ANX) and 13 non-anxious control subjects completed a decision-making task while functional magnetic resonance imaging scans were acquired.

Results: The ANX group endorsed greater task-related anxiety and less certainty than control subjects on a post-task questionnaire. Compared with control subjects, the ANX group did not demonstrate hyper-responsivity of brain regions as hypothesized. Across groups, IU was positively correlated with activity in several frontal and limbic regions. Further analyses identified subgroups within the ANX group: those with high IU activated frontal/limbic regions, whereas those with low IU and less anxiety during the task deactivated the same regions in response to uncertainty.

Conclusions: Results substantiate the hypothesized link between IU and neural responses to uncertainty in some adolescents with anxiety disorders. Our findings, if replicated, suggest that trait measures, such as IU, can significantly improve our understanding of the neurobiological basis of pediatric anxiety disorders.