A pervasive developmental disorder consisting of gross and sustained impairment in social interaction and communication; restricted and stereotyped patterns of behavior, interest, and activities; and abnormal development prior to age 3 years manifested by delays or abnormal functioning in social development, language communication, or play. Specific symptoms may include impaired awareness of others, lack of social or emotional reciprocity, failure to develop peer relationships appropriate to developmental level, delay or absence of spoken language and abnormal nonverbal communication, stereotyped and repetitive language, idiosyncratic language, impaired imaginative play, insistence on sameness (e.g., nonfunctional routines or rituals), and stereotyped and repetitive motor mannerisms.