ASD spectrum disorder DSM 5: MANDATORY 1 & 2: (1) Social communication & interaction (Developing, maintaining, & understanding relationships) (2) Restricted, repetitive patterns of behaviour, interests, or activities (RRBs) (Stereotyped movements, use of objects, or speech, Insistence on sameness, inflexibility, ritual behaviours, Highly restricted/fixated abnormal interests, Hyper- or hypo-reactivity to sensory input. (3) Present in early development: Symptoms recognized during 2yo. (4) Symptoms cause sig impairment in social, occupational functioning - Even able adults less likely to live independently commensurate w/ IQ (Howlin, 2000). (5) Symptoms not better explained by intellectual disability or developmental delay - 2 core domains of deficits. Social communication disorder diagnosed if no RRBs (Restrictive Repetitive patterns of Behaviour).