Autistic disorders belong to a broad spectrum of clinically heterogeneous, pervasive development disorders, according to DSM-IV. Clinical features usually appear during the first three years of life. Children and adults with autism typically have difficulties in verbal and non-verbal communication and social interactions, and show repetitive patterns of behavior and interest. Although the exact etiology of autism is unknown, both genetics and environment are believed to play important roles. Diagnosis is based on clinical criteria and requires an experienced doctor. There is no cure for autism yet, but early intervention may improve some behavioral problems and subsequent IQ level.