Two things to discuss. The nonverbal comforting from the dog and the holding stroking of the dog this releases a chemical oxytocin in the body. Oxytocin is linked to bonding and social interaction. Oxytocin too much or too little is linked to autism. More research needs to be done on "meltdowns" experienced by autistic people and the presence of self-injury during or shortly after said "meltdown". I am 38 and late last year I was diagnosed with autism. Autism is a life long condition and a spectrum. In my teens I would have "meltdowns" walk out of school, run off or self injure cut, hit or put cigarettes out on myself I would do this privately because I did not want attention I needed a release