Another study looking at reactivity, or response instead of steady state measures to stratify clinical response.  The relaxation response I first noticed with acupuncture may be getting at this same type of phenomenon.  Unfortunately, in their study, they don’t report the HRV results, which leads me to think they were too erratic.  Author kindly forwarded me a copy of the article here.stress reactivity predicts symptom improvement in anxiety
J Affect Disord. 2016 Feb 9;196:190-199.
Stress reactivity predicts symptom improvement in children with anxiety disorders.

Author information

  • 1Department of Child and Adolescent Psychiatry/Psychology, Erasmus Medical Center Rotterdam/Sophia Children’s Hospital, Rotterdam, The Netherlands. Electronic address: g.dieleman@erasmusmc.nl.
  • 2Department of Developmental Psychology, Faculty of Psychology and Education, VU University, Amsterdam, The Netherlands.
  • 3Department of Psychiatry, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
  • 4Department of Child and Adolescent Psychiatry/Psychology, Erasmus Medical Center Rotterdam/Sophia Children’s Hospital, Rotterdam, The Netherlands.
  • 5Department of Child and Adolescent Psychiatry/Psychology, Erasmus Medical Center Rotterdam/Sophia Children’s Hospital, Rotterdam, The Netherlands; Department of Psychiatry, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.

Abstract

BACKGROUND:

We examined the longitudinal associations of autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal (HPA) axis rest and reactivity measures with anxiety and depressive symptoms at one-year follow-up in children with anxiety disorders.

METHODS:

In a clinical sample of 152 children with a primary DSM-IV anxiety disorder, aged 8 to 12 years, anxiety and depressive symptoms were assessed with the Multidimensional Anxiety Scale for Children and the Children’s Depression Inventory at pre-treatment baseline and one year later, after treatment with cognitive behavioral therapy. At baseline, children participated in a 70min stress task. Salivary cortisol was measured directly prior to and 20min post stress task. Skin conductance level (SCL), heart rate and high frequency heart rate variability (HRV) were continuously measured during rest and the stress task. To investigate if rest or reactivity measures predicted anxiety and depressive symptoms at one year follow-up, linear regression analyses were conducted for rest and reactivity measures of SCL, heart rate, HRV and cortisol separately.

RESULTS:

Higher SCL reactivity predicted less decrease of anxiety symptoms at one-year follow-up. Cortisol reactivity showed a weak association with depressive symptoms at one-year follow-up: lower cortisol reactivity predicted less decrease in depressive symptoms.

LIMITATIONS:

Only self-reported anxiety and depressive symptoms were used. However, all predictors were objective biological measures, hence there is no risk of shared method variance bias.

CONCLUSIONS:

These findings suggest that pre-treatment HPA and ANS responsiveness to stress are predictive biomarkers for a lack of symptom improvement in children with a clinical anxiety disorder.