Startle potentiation to unpredictable threat predicts adolescent development of generalized anxiety disorder.

Background: An elevated startle reflex in anticipation of unpredictable threat has been associated with concurrent anxiety disorders. However, only one study to date has examined whether startle potentiation in anticipation of unpredictable threat predicts the development of anxiety disorders.

Method: In a community sample of 309 adolescents, we examined whether the startle reflex in anticipation of predictable or unpredictable threat at age 15 predicted onset of generalized anxiety disorder (GAD) and social anxiety disorder (SAD) at age 18. To evaluate the specificity of these relationships, we also examined the development of depressive disorders. Startle reflex was measured using the no, predictable, and unpredictable threat task at age 15. Semi-structured diagnostic interviews were administered at both waves to assess lifetime anxiety disorders and depression.

Results: Average startle reflex and startle potentiation to unpredictable, but not predictable, threat at age 15 predicted GAD at age 18, independent of lifetime GAD through age 15 and lifetime depression through age 18. Startle responses at age 15 did not predict SAD or depression at age 18.

Conclusions: The present study suggests that elevated startle potentiation in anticipation of unpredictable threat is a risk factor for the development of GAD in adolescence.