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

A longitudinal study of 309 adolescents found that elevated startle reflex responses to unpredictable (but not predictable) threat at age 15 predicted the onset of generalized anxiety disorder by age 18, independent of prior anxiety history. Startle responses did not predict social anxiety disorder or depression, suggesting this biomarker is specific to GAD development risk.