Table 1.

DSM-5 diagnostic criteria for ASD

Domains	Criteria (with examples)
1.  Impairment in social interaction and communication (all three subcriteria required)	Social and emotional reciprocity: • Difficulty initiating or responding to social interactions • Reduced spontaneous sharing of interests, achievements, or emotions (e.g., enjoyment) Impairment of nonverbal behaviours: • Reduced eye contact to communicate • Reduced use of gestures (e.g., pointing, waving) • Reduced facial expressiveness, appears disconnected • May use someone’s hand to get a desired object without making eye contact Failure to develop and maintain relationships: • Reduced or atypical interest in peers • Difficulty engaging in imaginative play with peers
2.  Abnormal and restricted, repetitive behaviours, interests, and activities (two of four subcriteria required)	Stereotyped speech and behaviours: • Repeats words, phrases (e.g., from television shows or movies) • Repetitive activities with objects (e.g., lining up pencils, toy figures) • Repetitive body, arm, hand, or finger movements (e.g., spinning around, hand-flapping, finger-flicking) • Transient stiff posturing of hands or whole body Insistence on sameness/resistance to change: • Wearing the same clothes (or only one colour) every day; eating the same food daily • Distress if route to preschool is changed Restricted, fixated interests: • Topics and/or objects that are unusually intense or narrowly-focused Hyper- or hypo-sensitivity to sensory input • Unusual reactions (e.g., distress or fascination with smells, sounds, textures, sights, and tastes)
3. Signs or symptoms must be present during early development but they may not be fully evident until later, when social demands exceed limited capacities, or they may be masked by learned strategies.
4. Symptoms interfere with everyday functioning.
5. Symptoms are not better explained by intellectual disability or global developmental delay.
6. ASD may occur with or without medical, genetic, neurodevelopmental, mental or behavioural disorders, or an intellectual or language impairment.
7. Level of severity for each of the two domains may be used to refine diagnosis: Level 1: Requiring support; Level 2: Requiring substantial support; Level 3: Requiring very substantial support. These levels may be difficult to determine at the initial time of diagnosis with very young children.

Data drawn from reference (1).

ASD Autism spectrum disorder.