Study Protocol: Pegasus: psychotherapy incorporating horses for 'therapy-resistant' adolescents with autism spectrum disorders, a study with series of randomised, baseline controlled n-of-1 trials.

Background: For people with autism spectrum disorder (ASD), daily life can be highly stressful with many unpredictable events that can evoke emotion dysregulation (ED): a strong difficulty with appropriately negative affect regulation. For some of the patients with ASD, treatment as usual does not prove to be effective for ED. They may be at risk of life-long impairment, development of other disorders and loss of motivation for most regular forms of therapy.