Table 1.

Examples of ASD symptoms, grouped as delineated in the DSM-5 criteria, then classified along positive, negative, and cognitive dimensions

	Positive symptoms	Negative symptoms	Cognitive symptoms
A1. Deficits in social-emotional reciprocity
Abnormal social approach	Intrusive initiations Use of others as tools Excessive verbosity
Failure of normal back and forth conversation	One-sided conversations Monologues Tangential speech	Failure to respond when name is called or when spoken to directly Failure to initiate conversation	Failure to understand humor, sarcasm, and non-literal language
Reduced sharing of interests		Lack of bringing, showing, pointing Lack of initiating or responding to joint attention
Reduced sharing of emotion	Aversive reaction to physical contact and affection	Lack of social smile Failure to share enjoyment Failure to offer comfort
Lack of initiation of or response to social interaction		Failure to initiate interactions with others
A2. Deficits in nonverbal communicative behaviors
Abnormalities in eye contact	Prolonged or overly intense eye contact	Reduced eye contact Gaze avoidance
Impairment in use and understanding of body language	Standing too close to interaction partners	Facing away from a listener
Abnormal volume, pitch, intonation, rate, rhythm, stress, prosody, or volume in speech	“Sing-song” or exaggerated intonation	Mechanical intonation
Deficits in understanding and use of gestures		Reduced nodding or shaking head Lack of descriptive gestures
Abnormalities in use and understanding of facial expressions	Exaggerated facial expressions	Limited range of facial expressions Limited communication of own affect Inability to recognize others’ nonverbal expressions
Lack of coordinated verbal and non-verbal communication		Failure to integrate multiple modes of communication
A3. Deficits in developing, maintaining, and understanding relationships
Difficulties in making friends	Excessive overtures that are off-putting to others Breaching conventions of social interactions, such as by being extremely directive or rigid	Inability to make and maintain relationships with developmentally matched peers Lack of friendships Lack of cooperative play Failure to respond to social approaches of other children	Lack of Theory of Mind or ability to take another’s perspective
Difficulties adjusting behavior to suit various social contexts	Inappropriate expressions of emotion, such as laughing or smiling out of context Socially inappropriate statements and questions	Failure to notice others’ lack of interest Lack of response to contextual cues Failure to notice other’s distress Failure to recognize when not welcome in play or conversation Limited recognition of social emotion
Difficulties in sharing imaginative play		Lack of imaginative play with peers
Absence of interest in peers		Lack of interest in peers Withdrawal and aloofness Preference for solitary activities
B1. Stereotyped or repetitive motor movements, use of objects, or speech
Stereotyped or repetitive speech	Pedantic speech Echolalia Idiosyncratic language Pronoun reversal Perseverative language	Failure to develop functional language
Stereotyped or repetitive motor movements	Repetitive hand movements Complex whole body movements Body tensing Abnormal postures, such as toe walking
Stereotyped or repetitive use of objects	Lining up toys or objects Repetitively turning lights on and off	Non-functional play with toys
B2. Insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal and nonverbal behavior
Adherence to routine	Specific sequences of behavior Insistence on rigidity in following specific routines		Cognitive inflexibility Black and white thinking Rigid adherence to rules, rituals, and routines
Excessive resistant to change	Difficulty with transitions Overreaction to trivial changes in environment or appearances		Insistence on sameness
Rigid thinking			Inability to understand humor Inability to understand nonliteral aspects of speech Excessively rigid, inflexibility, or rule-bound thought
B3. Highly restricted, fixated interests that are abnormal in intensity or focus
Preoccupations and obsessions	Preoccupation with particular, narrow, or unusual topics of interest to an excessive degree	Narrow range of interests	Perseverative thinking patterns Preoccupation with numbers, letters, symbols Splinter skills, such as hyperlexia Overly perfectionistic cognitive style
Excessively circumscribed or perseverative interest	Persistent focus on same few objects, topics, or activities
Excessive focus on non-relevant or non- functional parts of objects	Focus on parts of objects, such as wheels on cars	Failure to use toys or objects as intended Lack of imagination
Attachment to unusual objects	Unusual attachment to specific objects
B4. Hyper- or hypo-reactivity to sensory input or unusual interest in sensory aspects of the environment
Unusual visual exploration	Close visual inspections of objects Peering out of the corner of one’s eyes Extreme fascination with watching movement
Apparent indifference to pain	Self-injurious behavior	Failure to show pain response to stimuli typically considered painful
In all domains of sensory stimuli, odd response to sensory input	Extreme distress to loud noises or particular clothing or food textures Persistent focus on sensory input, such as fans spinning or water running	Lack of response to sound, sight, or touch Under-responsiveness to sensory stimuli
Unusual sensory exploration with objects	Licking or sniffing objects