Theses and Dissertations

Issuing Body

Mississippi State University


Nicodemus, Molly C.

Committee Member

Cavinder, Clay A.

Committee Member

Lemley, Caleb O.

Committee Member

Prince, Pauline

Date of Degree


Document Type

Graduate Thesis - Open Access



Degree Name

Master of Science (M.S.)


College of Agriculture and Life Sciences


Department of Animal and Dairy Sciences


Psychotherapy incorporating equine interaction (PIE) is emerging as an effective treatment for substance use disorder (SUD), but research is limited concerning physiological impacts during substance withdrawal. This study investigated impacts of PIE on salivary cortisol concentrations, heart rate, anxiety, and depression during SUD withdrawal. Heart rate and cortisol concentrations were measured in horses to determine potential human-horse coupling. Saliva samples and heart rates were collected pre and post PIE from residential SUD patients (n=18) and their therapy horses (n=4) during and following the withdrawal period. Participants (n=10) also completed a survey measuring anxiety and depression (P = 0.05). A strong negative correlation was found within the changes seen in human and horse cortisol concentrations during week two (r = -0.9, P < 0.01). Human heart rates decreased in week two (P = 0.01) and anxiety and depression decreased by week four (P ≤ 0.05). Results indicate psychotherapy incorporating equine interaction does not negatively impact stress parameters as the SUD patient progresses through the withdrawal period, and this intervention resulted in improved feelings of anxiety and depression.