Background: Few studies have looked at the very long-term outcome of individuals with autism who were diagnosed in childhood.
Methods: A longitudinal, prospective, community-based follow-up study of adults who had received the diagnosis of autism (classic and atypical) in childhood (n = 105) was conducted. A structured interview (the Diagnostic Interview for Social and COmmunication disorders--the DISCO) was used in order to evaluate symptoms and symptom patterns 13-22 years after original diagnosis. Childhood measures, including IQ-level at time of childhood diagnosis and communicative speech registered before age 5 years, were studied in relation to the presence of autism symptoms at follow-up.
Results: The classical and atypical autism groups were fairly homogeneously impaired in terms of symptoms in the social interaction category whereas other common childhood autism symptoms, including maladaptive and stereotyped behaviours, were more variable in the study group at follow-up. Odd responses to sensory stimuli were still extremely common. Speech before 5 years of age, IQ, gender, diagnosed medical disorder and onset of epilepsy before 5 years were variables that correlated to outcome on the DISCO algorithm for autistic spectrum disorders (Wing & Gould, 1979) concerning style and quality of social interaction, communication style and pattern of self-chosen activities.
Conclusions: Social interaction problems were still present in the vast majority of adults with autism/atypical autism, but behavioural impairments were much more variable in adulthood. Almost all cases were reported to show persistent perceptual problems. Certain childhood measures were found to prospectively predict adult social interaction style, communication type, and pattern of self-chosen activities, which still met diagnostic criteria for autism/atypical autism in adulthood.