Verbal skills were assessed at approximately ages 2, 3, 5, and 9 years for 206 children with a clinical diagnosis of autism (n = 98), pervasive developmental disorders-not otherwise specified (PDD-NOS; n = 58), or nonspectrum developmental disabilities (n = 50). Growth curve analyses were used to analyze verbal skills trajectories over time. Nonverbal IQ and joint attention emerged as strong positive predictors of verbal outcome. The gap between the autism and other 2 groups widened with time as the latter improved at a higher rate. However, there was considerable variability within diagnostic groups. Children with autism most at risk for more serious language impairments later in life can be identified with considerable accuracy at a very young age, while improvement can range from minimal to dramatic.

Background The range of outcomes for young adults with Autism Spectrum Disorders (ASD) and the early childhood factors associated with this diversity have implications for clinicians and scientists. Methods This prospective study provided a unique opportunity to predict outcome 17 years later for a relatively large sample of children diagnosed with ASD at 2-years-old. Diagnostic and psychometric instruments were administered between 2 and 19 with data from 2, 3, and 19 included in this paper. Clinicians administered tests without knowledge of previous assessments whenever possible. Caregivers provided additional information through questionnaires. Results Significant intellectual disabilities at 19 were predicted by age 2 about 85% of the time from VIQ and NVIQ scores together, though prediction of young adult outcome for youths with average or higher intelligence was more complex. By 19, 9% of participants had largely overcome core difficulties associated with ASD and no longer retained a diagnosis. These youths with Very Positive Outcomes were more likely to have participated in treatment and had a greater reduction in repetitive behaviors between age 2 and 3 compared to other Cognitively Able youths (VIQ ≥70) with ASD. Very Positive Outcome youths did not differ phenotypically from Cognitively Able ASD individuals at 2 but both groups differed from Cognitively Less Able individuals (VIQ < 70). Conclusion Those most at risk for intellectual disabilities and ASD can be reliably identified at an early age to receive comprehensive treatment. Findings also suggest that some cognitively able children with ASD who participate in early intervention have very positive outcomes, although replication with randomized, larger samples is needed. In order to improve understanding of very positive outcomes in ASD, future research will need to identify how variations in child characteristics and environmental factors contribute to the nature and timing of growth across individuals and areas of development.

Background: Delayed, abnormal language is a common feature of autism and language therapy often a significant component of recommended treatment. However, as with other disorders with a language component, we know surprisingly little about the language trajectories and how varied these might be across different children. Thus, we know little about how and when language problems might resolve, whether there are periods of relative stability or lack of change and what periods might offer more favourable circumstances for intervention. Methods: Expressive and receptive language was measured on six occasions between age 2 and 19 on a cohort of 192 children initially referred for autism. Latent class growth models were fitted to characterize the patterns of heterogeneous development. Results: Latent class growth analysis identified seven classes. Between age 6 and 19, all classes tracked in parallel. Between ages 2 and 6, development was more heterogeneous with considerable variation in relative progress. In all groups, receptive and expressive language developed very largely in tandem. Conclusions: The results confirmed previous analysis of children with specific language impairment where progress beyond age 6 was remarkably uniform. Greater variation was evident before this age with some groups making clearly better or worse progress compared to others. While this developmental heterogeneity may simply be a reflection of variation in preexisting and unchanging biological disposition, it may also reflect, at least in part, greater sensitivity in the early years to environments that are more or less supportive of language development. These findings contribute to the case for the importance of early intervention.

The current study prospectively examined trajectories of change in symptoms of irritability, hyperactivity, and social withdrawal, as well as predictors of such behaviors from age 9 to 18 for youths with autism spectrum disorder (ASD) and a comparison group with nonspectrum developmental delays. Children with more severe core features of autism had consistently higher irritability and hyperactivity scores over time than those with broader ASD and nonspectrum delays. Across all diagnoses, behaviors related to hyperactivity showed the greatest improvement. Social withdrawal worsened with age for a substantial proportion of youths with ASD but not for the nonspectrum comparison group. Compared with nonspectrum youths, children with ASD showed greater heterogeneity in trajectories for maladaptive behaviors.