Signs and symptoms may differ from person to person and are evident early in life, typically in the first 2 years. Some individuals can begin to show signs and symptoms at about 6 to 12 months, though others have symptoms that are noticed later in childhood. The
American Academy of Pediatrics recommends screening for ASD at 18 and 24 months.
If there are concerns for possible ASD, an individual may be referred to a specialist (such as a psychologist or neuropsychologist) for evaluation. Generally, ASD can be diagnosed around 18-24 months of age or later, though some individuals remain undiagnosed - including some adults and individuals with high-functioning ASD.
Testing for ASD may consist of interviews, questionnaires, neuropsychological tests, and observation-based assessments that look at social skills, cognition, and behavior.
ASD can co-occur with other conditions (such as intellectual disorders, ADHD, anxiety, depression, etc.), and can be associated with difficulties in aspects of thinking (such as attention, complex thinking, verbal abilities, etc.), so comprehensive assessment of an individual’s social, behavioral, developmental, adaptive, and cognitive skills can help with diagnosis and treatment planning.