The development of siblings' understanding of autism spectrum disorders.

While professionals commonly advocate sharing information about autism spectrum disorders with siblings, no guidelines currently exist that describe what types of information might be relevant for siblings at different ages. To address this issue, the interviewing method described by Bibace and Walsh (1979, 1980), which measures cognitive sophistication in thinking about illness, was adapted to examine perspectives on autism spectrum disorders. Sixty-three siblings of individuals with autism or related disorders were interviewed using this measure. Parents were given the same interview as their child, and asked to predict their child's responses. Children's reasoning became more mature with age, but developed at a delayed rate compared to norms for illness concepts. Although accurate in estimating their child's understanding of the definition and cause of their sibling's diagnosis, parents tended to overestimate their child's understanding of the disorder's impact.