Investigating the Neurological Efficacy of Equine Assisted Psychotherapy in Treatment of Post-Traumatic Stress Disorder

Arpita Ghosh

Domesticated animals like horses being used for therapeutic purposes dates long back in history. Their inclusion in medical treatment began in the second century (Granados & Agís, 2011). Horses are the most popular animals in the field of animal therapy, because of their ability to immediately respond to the actions of the handler, and mirror their emotions (Clarke, 2021). Today their therapeutic effectiveness has been recognized and utilized especially for the treatment of mental illnesses through a clinical tool called Equine Assisted Psychotherapy (APA, 2020). To understand the reason behind the efficacy of this approach it is important to acknowledge the neurological implication associated with its symptomatic improvement of specific disorders. Keeping that in mind, this blog aims to discuss the effectiveness of Equine Assisted Psychotherapy, specifically in the alleviation of Post-Traumatic Stress Disorder (PTSD) symptoms, and the neurological mechanisms connected to its outcomes. 

Following this, it is imperative to first understand how Equine Assisted Psychotherapy (EAP) operates. Unlike traditional psychotherapy where the therapist plays a key role in facilitating treatment, in EAP, the horse serves as an important point of interaction with the clients (Arnon et.al., 2020). With the help of experienced psychotherapists and equine specialists, clients communicate with horses through tasks that facilitate engagement in self-reflection, and mindfulness (Arnon et.al., 2020).

Now that how EAP functions is established, it is essential to know the neurological mechanisms contributing to effectiveness in relation to the symptomatic improvement of PTSD clients. PTSD is associated with structural and functional impairment in brain parts like the amygdala, medial prefrontal cortex, hippocampus, and thalamus which are known to be responsive to stress (Bremner, 2006; Zhang, 2019; Hooley, et al., 2021). This has been backed by research using neuroimaging techniques like multimodal magnetic resonance imaging (MRI). These techniques have shown that PTSD is not just linked with changes in the grey matter volume (GMV) of the caudate and the thalamus, but is also associated with changes in connectivity in the caudate, found near the thalamus. The caudate forms a connective network among brain parts, which is known as caudate functional connectivity (cFC) (Nakamura, 2020). This, therefore, makes it clear that abnormalities of the cFC and GMV is linked to the development of PTSD symptoms.

Clients with PTSD show symptoms like avoidant behavior, and reduction in reward learning, which is associated with a reduction in cFC (Balleine, 2007; Seidemann et.al., 2021). Furthermore, they also have increased GMV in the brain areas, which is linked with commonly experienced symptoms by PTSD clients like emotional dysfunction, hyperarousal, and negative moods (O’Doherty et.al., 2017; Zhang, 2018). This means that strengthening of the cFC and decrease in GMV could be linked to symptomatic improvement in PTSD clients.

Observable changes in these brain parts of PTSD clients have also been correlated with symptomatic alleviation in response to EAP (Earles et al.,2015). To confirm this, Zhu et al. (2021) conducted a study on 20 veterans with PTSD, who were non-responsive to other forms of treatment. In this study, the veterans underwent 8 weeks of EAP sessions, and multimodal MRIs of their brains were compared before and after the treatment duration (Zhu et al., 2021). The results revealed that after undergoing EAP, clients’ brains showed a reduction in GMV of the thalamus and caudate. and strengthening of the cFC. Thus, as mentioned before since cFC is liked with the regulation of reward learning mechanisms and avoidant behavior, its strengthening can correspond to an enhancement of the clients’ reward system, and sustenance of symptomatic improvement (Seidemann, 2021; Zhu et al., 2021). Furthermore, the effectiveness of EAP was confirmed by observing the reduction of PTSD symptoms in clients, and by noting the increase in their clinical scores on the Clinician-Administered PTSD Scale for DSM V, post EAP session (Zhu, et.al, 2021). Hence, this shows the association between the effectiveness of EAP and its underlying neurological mechanism in correspondence to the reduction of PTSD symptoms.  

Additionally, the healing power of horses in the treatment of PTSD clients can also be attributed to the ‘biophilia’ response- the innate and evolutionary instincts of humans to interact with animals because of its association with psychological, social, and physiological benefits (Beck, 2014). The evolutionary animal-human bond perhaps provides an alternative explanation as to why the veterans, in Zhu et al.’s (2021) study, who were non-responsive to other forms of treatments, showed reduced PTSD symptoms, after undergoing EAP. Hence, mental health professionals must consider EAP, as a complementary therapeutic service alongside traditional psychotherapy, if not in isolation. This is because the conventional talk-therapy approach, in the therapist’s chamber, can seem uninviting to several clients. In such cases incorporating horses in the therapeutic approach can make the environment more welcoming (Clarke, 2021). These horses are sensitive and responsive to clients’ emotions and can mirror them to convey a sense of understanding. Thus, EAP, helps clients develop trust in the horse, and feel comfortable unwinding their difficulties, aiding the process of wellbeing (Clarke, 2021).

With that being said, it is imperative to note that EAP, like other therapies, has its constraints. For instance, the fear of large animals, horse-related allergies, the possibility of accidents, and cultural differences in attitudes towards horses could tamper the animal-human bond, vital for the effectiveness of this treatment (Dunlop & Tsantefski, 2017; Mueller & McCullough, 2017). Mental health practitioners must keep in mind these limitations, before conducting this therapy.

In conclusion, Equine Assisted Psychotherapy (EAP) can perhaps be effective along with traditional psychotherapy, in the treatment of disorders associated with abnormal changes in the brain like PTSD. This is possibly achieved by the strengthening of caudate functional connectivity and reduction in grey matter volume in specific brain areas. These changes corresponded to symptomatic improvements in PTSD clients. Despite the effectiveness of EAP, there is limited literature on its neurological implications. Further research in understanding the neuro-clinical association of EAP is necessary to establish the validity of this approach, and alleviate symptoms of other psychological disorders which could possibly have neurological links, like, anxiety, depression, attention-deficit-hyperactivity disorder, and schizophrenia.

 

References

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