Inclusion Criteria:  Clinical diagnosis of autism spectrum disorder or attention-deficit hyperactivity disorder defined by the DSM-5 criteria, made by board-certificated child psychiatrists Ages range from 5 to 18 Both parents are Han Chinese Subjects and their parents consented to have repeated assessments at 2 to 3 years later  Exclusion Criteria:  Comorbidity with DSM-5 diagnoses of ADHD (TDC group), ASD (ADHD and TDC groups), schizophrenia, schizoaffective disorder, delusional disorder, other psychotic disorders, organic psychosis, schizotypal personality disorder, bipolar disorder, depression, severe anxiety disorders or substance use Comorbidity with neurological or systemic disorders Having a first degree relative who may have ASD based on family history method assessment (ADHD and TDC groups)