Psychophysiological assessment of stress reactivity and recovery in anxiety disorders.

The present study aimed to examine changes in psychophysiological arousal from baseline to a stressor phase (reactivity) and from the stressor phase to a second resting phase (recovery) in patients with anxiety disorders. Fifty adult patients with DSM-5 anxiety disorders (panic disorder, generalized anxiety disorder, or social anxiety disorder) and 28 healthy control (HC) participants underwent psychophysiological monitoring including electrocardiogram, respiration rate, electrodermal activity, gastrocnemius electromyograph, and end-tidal CO2 for a 3-min resting phase, a 6-min mild stressor phase, and a 3-min recovery phase. Anxious patients then went on to receive naturalistic cognitive-behavioral therapy (CBT) in a specialty outpatient clinic. Results for the reactivity phase indicated that compared to HCs, patients with social anxiety disorder exhibited heightened psychophysiological reactivity while patients with panic disorder and generalized anxiety disorder exhibited attenuated reactivity. Results for physiological recovery (return to baseline after the stressor was withdrawn) were mixed, but provided some support for slower autonomic recovery in patients with generalized anxiety disorder and panic disorder compared to HCs. Participants with all anxiety disorders exhibited diminished change in high frequency heart rate variability compared to HCs. Generally, psychophysiological reactivity and recovery were not associated with CBT outcome, though exploratory analyses indicated that greater respiration rate reactivity and stronger respiration rate recovery were associated with better CBT outcomes in patients with panic disorder.

The dose-response curve in cognitive-behavioral therapy for anxiety disorders.

Previous studies examining the dose-response curve in psychotherapy have suggested that 11-19 sessions may be necessary for at least 50% of individuals to show clinically significant improvement. However, this curve has not been examined specifically for cognitive-behavioral therapy (CBT) for anxiety disorders, for which a more rapid recovery curve may be expected. Survival analysis was used to assess the dose-response curve for 201 patients with anxiety disorders who received weekly CBT at an anxiety specialty clinic. The primary outcome measure was the Outcome Questionnaire-45.2, which patients completed prior to each treatment session. Sixty-four percent of the sample achieved reliable change, and this response occurred in approximately five sessions on average. Fifty percent of the sample achieved clinically significant improvement, which occurred in approximately eight sessions on average. The findings suggest that earlier response may be expected in CBT for anxiety disorders, and are discussed in terms of potential ways to further improve response rates for this treatment.