Autism Spectrum Disorder is classified as a developmental disorder and therefore is not considered a “mental illness”. Autism can manifest itself from being severely impaired (IE non-verbal) to “high-functioning”. Individuals who are mildly impaired all will show a deficit in their social relationships, such as difficulty in making friends with peers, impaired ability to converse with others and difficulty in connecting emotionally with others. So Asperger’s is a valid diagnosis under the category of Developmental Disabilities. I do not know what the data shows, if any, regarding a link between Asperger’s and violence. But part of being a psychotherapist is conducting a risk assessment on your patients and then making an evidence-based decision. I think it would be fair to say that some syndromes-both developmental and psychiatric – would lead a therapist to assess, more readily than others, the individual’s risk of doing harm to himself or others. HIPAA does permit a therapist to report to police, etc. if they determine that a person is in imminent danger to themselves or others. On the other hand, I agree with Frank that most violent crime is committed by people with no “mental” (or other medical diagnosis) illness.