Behaviorally inhibited children face increased risk for anxiety disorders, although factors that predict which children develop a disorder remain poorly specified. The current study examines whether the startle reflex response may be used to differentiate between behaviorally inhibited adolescents with and without a history of anxiety.

Participants were assessed for behavioral inhibition during toddlerhood and early childhood. They returned to the laboratory as adolescents and completed a fear-potentiated startle paradigm and a clinical diagnostic interview (Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version). Magnitude of the startle reflex was examined at baseline and during cues associated with safety and threat.

Only adolescents who showed high levels of behavioral inhibition and had a lifetime occurrence of anxiety disorders showed increased startle reactivity in the presence of safety cues. Neither behavioral inhibition nor diagnosis was related to startle reactivity during threat cues.

These results suggest that neurobiological measures, such as the startle reflex, may be a potential risk marker for the development of anxiety disorders among behaviorally inhibited adolescents. These methods may enhance our ability to identify vulnerable individuals before the development of anxious psychopathology. J. Am. Acad. Child Adolesc. Psychiatry, 2009;48(6):610–617.