EFP is defined as an interactive process in which a licensed mental health professional working with or as an appropriately credentialed equine professional partners with suitable equine(s) to address psychotherapy goals set forth by the mental health professional and the client.

The concept that horses might be helpful or healing to people struggling with mental health issues is based on the idea that horses (as domesticated prey animals) are extremely sensitive to changes in the human being (as a predatory creature). Due to their sensitivity, horses react and respond to people differently based upon the person's emotional state. Since we know that emotional states in human beings also impact our physiology, it only makes sense that horses can smell or sense (using their vomeronasal organ) those changes. The horse acts as a large biofeedback machine, providing the client and the therapist with information regarding the client's moods and changes within those moods. If a client arrives anxious the horse will act and respond one way. If the client is able to reduce his or her anxiety, the horse's behaviors will also change. This provides a plethora of information and skill building opportunities for both the client and the therapist.