Effects of Equine Assisted Activities on Veterans With Post-traumatic Stress Disorder

The study will examine the effects of eight weeks of equine assisted activities (EAA) on co-regulation, basal physiological values, and symptom severity in veterans with post-traumatic stress disorder (PTSD). Heart rate, respiration rate, surface electromyography (EMG) and plasma concentrations of cortisol, epinephrine, norepinephrine, and oxytocin will be measured at rest and during dyadic interaction tasks (human to human or human to horse) to assess effects of EAA on these measures. Additionally, standard and regularly used questionnaires will be used to monitor PTSD symptom severity during the study and 6-month follow-up period. EAA is expected to lower PTSD symptom severity, and mitigate other physiological changes associated with PTSD.

Participants will be randomly assigned to an equine assisted activities intervention or wait-listed control for eight weeks. At the end of the eight week period, participants assigned to the wait-listed control will be offered the opportunity to participate in the equine assisted activities intervention.

Participants in this arm will take part in eight weekly thirty minute sessions of equine facilitated learning where they interact with a horse and learn basic horsemanship skills.

Change from Baseline to the Conclusion of 8 weeks of EAA in PTSD Symptoms as Assessed by PCL-5 & Brief Symptom Inventory

The Brief Symptom Inventory and PTSD Checklist for DSM-5 are questionnaires used to assess the presence and severity of post-traumatic stress disorder symptoms.

Symptoms will be assessed prior to the intervention and immediately following the eight week intervention.

Change from Baseline to 2-months After the Conclusion of EAA in PTSD Symptoms as Assessed by PCL-5 & Brief Symptom Inventory

The Brief Symptom Inventory and PTSD Checklist for DSM-5 are questionnaires used to assess the presence and severity of post-traumatic stress disorder symptoms.

Change from Baseline to 6-months After the Conclusion of EAA in PTSD Symptoms as Assessed by PCL-5 & Brief Symptom Inventory

The Brief Symptom Inventory and PTSD Checklist for DSM-5 are questionnaires used to assess the presence and severity of post-traumatic stress disorder symptoms.

Co-regulation of heart rate between horse and human will be assessed once a week during a 30 min session for 8 weeks..

Co-regulation will be assessed through collection of serial blood samples and subsequent measurement and modeling of plasma cortisol.

Co-regulation of cortisol between horse and human will be assessed once a week during a 30 min session in weeks 1,4, and 8 of an 8 week period.

Co-regulation will be assessed through collection of serial blood samples and subsequent measurement and modeling of plasma oxytocin.

Co-regulation of oxytocin between horse and human will be assessed once a week during a 30 min session in weeks 1,4, and 8 of an 8 week period.

Co-regulation will be assessed through collection of serial blood samples and subsequent measurement and modeling of plasma epinephrine.

Co-regulation of epinephrine between horse and human will be assessed once a week during a 30 min session in weeks 1,4, and 8 of an 8 week period.

Co-regulation will be assessed through collection of serial blood samples and subsequent measurement and modeling of plasma norepinephrine.

Co-regulation of norepinephrine between horse and human will be assessed once a week during a 30 min session in weeks 1,4, and 8 of an 8 week period.

Co-regulation will be assessed through collection of surface electromyography (sEMG) from the masseter, brachiocephalas, and cervical trapezius muscles and subsequent modeling.

Co-regulation of muscle activity between horse and human will be assessed once a week during a 30 min session over an 8 week period.

Changes in co-regulation of heart rate during dyadic (human-human) interactions following 8 weeks of EAA

Co-regulation will be assessed through the measurement and modeling of heart rate during gazing, not looking, resting, and mimicking tasks.

Co-regulation will be assessed prior to the intervention and immediately following the eight week intervention.

Social motor synchrony will be assessed through the measurement and modeling of gross motor movement during a pendulum swinging task.

Social motor synchrony will be assessed prior to the intervention and immediately following the eight week intervention.

Resting heart rate will be assessed prior to the intervention and immediately following the eight week intervention.

Plasma concentrations of cortisol will be measured via immunoassay following blood draws during rest.

Cortisol concentrations will be assessed prior to the intervention and immediately following the eight week intervention.

Plasma concentrations of oxytocin will be measured via immunoassay following blood draws during rest.

Plasma oxytocin concentrations will be assessed prior to the intervention and immediately following the eight week intervention.

Plasma concentrations of epinephrine will be measured via immunoassay following blood draws during rest.

Plasma epinephrine concentrations will be assessed prior to the intervention and immediately following the eight week intervention.

Plasma concentrations of norepinephrine will be measured via immunoassay following blood draws during rest.

Plasma norepinephrine concentrations will be assessed prior to the intervention and immediately following the eight week intervention.

Only males are eligible for inclusion in the study because the hormones being measured are impacted by the menstrual cycle in females.

Inclusion Criteria: male was deployed and experienced combat in Iraq or Afghanistan between 18 and 65 years of age Exclusion Criteria: female amputation severe traumatic brain injury schizophrenia, bi-polar disorder, or substance dependence in the last 3 months pacemaker allergies to horses previous enrollment in equine assisted activities or psychotherapy in an equine environment