Measuring the association between behavioural services and outcomes in young children with autism spectrum disorder

Background: Children with autism spectrum disorder (ASD) receive a wide range of services. Aims: To examine the association between behavioural services received by children with ASD between ages 2 and 5 years and outcomes during primary school years. Methods: A total of 414 preschool-aged children diagnosed with ASD were enrolled at five Canadian sites and were assessed within four months of diagnosis (T1), six months later (T2), 12 months later (T3), at school entry (T4), and then annually (T5-T8) to 11 years of age. The association between the receipt of behavioural services during T1 to T3 and T8 outcomes related to adaptive behaviour and behavioural problems was modelled using linear regressions adjusted for immigrant status, family income, child's age at diagnosis, site, sex assigned at birth, and baseline (T1) outcome. Results: Children who received behavioural services during at least one time period from T1 to T3 did not have significantly different outcomes at T8 than children who did not receive any behavioural services. Implications: Pre-school use of behavioural services was not found to affect outcomes during later childhood. Numerous challenges accompany studies of the association between pre-school service use and later outcomes in a heterogeneous ASD sample. Recommendations for study design are provided.