Under advisement from the NSAC, the DSM-III (1980) turned what was previously defined as childhood schizophrenia into three kinds of "pervasive developmental disorder" (PDD). "Infantile autism" began before a child was 30 months old, and "childhood onset pervasive developmental disorder" began between 30 months and 12 years. A third variety, "atypical pervasive developmental disorder" was similar but lesser than the other two, and could begin at any time. "Elective mutism" was now categorised as in independent condition.
