The Treatment of Depression With Yoga and Walking
Condition: Depression; Major Depressive Disorder; PTSD; Anxiety
MeSH terms: Depression; Depressive Disorder; Depressive Disorder, Major
Study type: Interventional

Summary: 
      This randomized controlled trial is designed to test the Vagal-gamma amino-butyric acid
      (GABA) Hypothesis that one of the mechanisms by which yoga-based practices improve mood and
      decrease anxiety is by correcting an autonomic system (ANS) imbalance with too much activity
      in the sympathetic nervous system (SNS) and too little activity in the parasympathetic
      nervous system (PNS). This imbalance is associated with under activity in the GABA system. It
      is hypothesized that yoga-based practices increase activity in the PNS by increasing
      respiratory sinus arrhythmia (RSA), which is associated with increased activity in the GABA
      system and decreased depressive and anxiety symptoms.
    

Detailed description: 
      Subjects with Major Depressive Disorder (MDD) will be randomized into two treatment groups, a
      yoga group (YG) and a walking group (WG). After screening and Scan 1, each subject will be
      randomized to a 12-week yoga or walking intervention consisting of two group sessions and
      three homework sessions a week.The primary dependent variable will be brain gamma
      amino-butyric acid (GABA) levels measured using magnetic resonance spectroscopy (MRS) in two
      regions of interest (ROI)s: the thalamus and the anterior cingulate. GABA levels will be
      measured three times: Scan 1 prior to randomization, Scan 2 after the 12-week intervention,
      and immediately after Scan 2, subjects will participate in either the yoga intervention or
      walking intervention, followed immediately by Scan 3. The secondary dependent variable will
      be changes in depressive symptoms, mood and anxiety measured by valid and reliable
      psychological instruments obtained before each scan and at screening, week-4, week-8 and
      week-12. The third dependent variable will be respiratory sinus arrhythmia (RSA) a component
      of heart rate variability (HRV) that is an accurately index of vagal influences on the heart.
      RSA will be measured scan 1, pre and post an intervention session depending on group
      assignment at week 4, 8 and 12 evaluations, pre and post the yoga or walking intervention
      between Scan 2 and 3.

      Aim 1: To complete 22 subjects in the yoga group and 22 subjects in the walking group for a
      total of 44 subjects with Major Depressive Disorder (MDD). Completion is defined at a
      baseline evaluation, a week-4 or week-8 evaluation and a week-12 evaluation with usable
      thalamic data for Scans 1, 2 and 3.

      Aim 2. To measure changes in GABA levels over time using a mixed linear model analogue of
      repeated measures analysis-of-variance with independent groups in regional GABA levels in MDD
      subjects assigned to yoga and walking interventions.

      Aim 3. To assess changes in psychological measurements and regional GABA levels over the
      course of the interventions using linear regression.

      Aim 4. To assess changes in PNS using Respiratory Sinus Arrhythmia (RSA) over the course of
      the study using linear regression.

      Aim 5. To assess changes in PNS, RSA and regional GABA levels over the course of the study
      using linear regression.
    

Intervention name(s): Iyengar Yoga; Walking
Intervention type(s): Behavioral; Behavioral
Other intervention name(s): Yoga
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Vagal-gamma amino-butyric acid (GABA); Yoga; Walking