A systematic review and meta-analysis of the long-term overall outcome of autism spectrum disorders in adolescence and adulthood

Objective: A systematic review and meta-analysis of studies reporting on the overall outcome in terms of a global measure of adjustment in children with autistic disorders followed up in adolescence and adulthood. Method: PubMed, PsycINFO, and EMBASE were systematically searched on 3rd of August 2015. Included studies were analyzed using random-effects models estimating event rates (%) and 95% confidence intervals (95% CI). Results: From 4350 records identified in the search, 15 studies covering 12 unique samples and a total of N = 828 individuals with autistic disorders were included in the analyses. An estimated 19.7% (95% CI: 14.2-26.6) had a good outcome, 31.1% (95% CI: 23.2-40.4%) a fair outcome, and 47.7% (95% CI: 36.6-59.0) a poor outcome. The meta-analysis showed strong evidence for heterogeneity. The subtype of childhood autism is a significant moderating factor on the risk of having a poor outcome at follow-up, whereas age at follow-up showed statistically significant but inconsistent associations with outcome status. Conclusion: The long-term outcome of almost half of all individuals with autistic disorders is poor. The subtype of autism in childhood may be a predictor for specific long-term outcomes, but in general, little is known about the pathways and predictors.