Attenuation of Anxiety-Potentiated Startle After Treatment With Escitalopram or Mindfulness Meditation in Anxiety Disorders.

Summary

Anxiety disorders are linked to heightened startle responses during unpredictable threat, a physiological marker called anxiety-potentiated startle (APS). In a study of 93 individuals with anxiety disorders and 66 healthy controls, APS was higher in the anxious group at baseline. After eight weeks of treatment with either escitalopram or mindfulness-based stress reduction, both treatment groups showed significantly greater reductions in APS compared to controls, with patients' APS levels falling into the range of healthy individuals. Fear-potentiated startle (FPS), a response to predictable threat, did not differ between groups at baseline nor change with treatment. These results validate APS as a biological correlate of pathological anxiety and provide evidence that mindfulness-based stress reduction can alter anxiety-related neurocircuitry similarly to medication.

Study at a glance

Abstract

Biological markers for anxiety disorders may further understanding of disorder pathophysiology and suggest potential targeted treatments. The fear-potentiated startle (FPS) (a measure of startle to predictable threat) and anxiety-potentiated startle (APS) (startle to unpredictable threat) laboratory paradigm has been used to detect physiological differences in individuals with anxiety disorders compared with nonanxious control individuals, and in pharmacological challenge studies in healthy adults. However, little is known about how startle may change with treatment for anxiety disorders, and no data are available regarding alterations due to mindfulness meditation training. Ninety-three individuals with anxiety disorders and 66 healthy individuals completed 2 sessions of the neutral, predictable, and unpredictable threat task, which employs a startle probe and the threat of shock to assess moment-by-moment fear and anxiety. Between the two testing sessions, patients received randomized 8-week treatment with either escitalopram or mindfulness-based stress reduction. APS, but not FPS, was higher in participants with anxiety disorders compared with healthy control individuals at baseline. Further, there was a significantly greater decrease in APS for both treatment groups compared with the control group, with the patient groups showing reductions bringing them into the range of control individuals at the end of the treatment. Both anxiety treatments (escitalopram and mindfulness-based stress reduction) reduced startle potentiation during unpredictable (APS) but not predictable (FPS) threat. These findings further validate APS as a biological correlate of pathological anxiety and provide physiological evidence for the impact of mindfulness-based stress reduction on anxiety disorders, suggesting that there may be comparable effects of the two treatments on anxiety neurocircuitry.