The relation between family familiarity with autism and developmental outcomes

The course of typical and atypical child development likely varies depending on families' understanding and support for their child's developmental needs. Analyzing longitudinal data ( $N=823$ children with autism) from 37 cohorts, we explored the relation between family familiarity with autism (defined by the presence of an autistic sibling) and children's cognitive and social development and emotional/behavioral outcomes. Greater autism familiarity was associated with earlier age of diagnosis, but also with neurodevelopmental outcomes, over and above age at diagnosis. In early childhood, children in the autism familiar group performed better on the Mullen Scales of Early Learning compared to those in the unfamiliar group (mean $T$ -score differences of 3-5). The later a child was diagnosed, the stronger the relation between autism familiarity and higher scores on receptive language and visual reception. Age at diagnosis was associated with more parent-rated problems on a range of Child Behavior Checklist scores in middle childhood and adolescence. Findings indicate that greater autism familiarity is associated with more positive cognitive developmental outcomes for children on the spectrum. Although correlational, these findings are consistent with the possibility that autistic children's development can be viewed as adaptation within a context that can be more (or less) supportive of children's developmental needs.