According to the Diagnostic and Statistical Manual of Mental Disorder – 5th Edition, the following are the diagnostic symptoms of autism spectrum disorder:
- Persistent deficits in social communication and social interaction across multiple contexts. This can include deficits in social-emotional reciprocity (i.e. abnormal social approach and failure of normal back-and-forth conversation; reduced sharing of interests, emotions, or affect; failure to initiate or respond to social interactions). This also can include deficits in nonverbal communicative behaviors used for social interaction (i.e. poorly integrated verbal and nonverbal communication; abnormalities in eye contact and body language or deficits in understanding and use of gestures; total lack of facial expressions and nonverbal communication). This may also include deficits in developing, maintaining, and understanding relationships (i.e. difficulty adjusting behavior to suit various social contexts; difficulty in sharing imaginative play or in making friends; absence of interest in peers).
- Restricted, repetitive patterns of behavior, interests, or activities. This can include stereotyped or repetitive motor movements, use of objects, or speech (i.e. motor stereotypes, lining up toys or repetitively flipping objects, echolalia, idiosyncratic phrases). This can also include insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal or nonverbal behavior (i.e. extreme distress at small changes, difficulties with transitions, rigid thinking patterns, greeting rituals, need to take same route or eat same food every day). This can be manifested by highly restricted, fixated interests that are abnormal in intensity or focus (i.e. strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interests). Finally, this can include hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment (i.e. apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement).