Criteria: Usually apparent by 2nd year of life. Deficits in social-emotional reciprocity, deficits in non-verbal communicative behaviours used for social interaction, deficits in enveloping, maintaining and understanding relationships. 2 of the following: stereotyped or repetitive motor movements, use of objects or speech, insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal or nonverbal behaviour, highly restricted, fixated interests that are abnormal in intensity or focus, hyper/hyporactivity to sensory input or unusual interest in sensory aspects of the environment. (Level 1, 2, 3)