Objectives: (a) To provide descriptive information about ASD-onset types among a large, well-characterized sample; (b) To determine whether parents’ beliefs about causes of ASD are associated with their reports of how ASD manifested in their children.
Methods: Data will be analyzed for children with ASD (probands; N = 2755; M age = 9 years, SD = 3.6 years, range = 4—17.9 years) who participated in the Simons Simplex Collection (SSC). Type of ASD onset will be categorized using data from the Autism Diagnostic Interview—Revised (ADI-R), according to the system used in Shumway et al. (2011). A subset of these families (n = 68) participated in an additional project that used an ASD-adapted version of the Revised Illness Perception Questionnaire (IPQ; Moss-Morris, et al., 2002) to query parents’ level of agreement with 21 possible causes of ASD. Frequencies of ASD-onset types will be presented for the entire SSC sample as a partial replication of Shumway et al. Frequencies of etiological beliefs about ASD have been calculated for the subset of families who completed the IPQ. Chi-square tests of homogeneity will be computed with data from the IPQ subsample to assess possible relationships between ASD-onset type and causal beliefs about ASD.
Results: The largest proportions of families agreed with 4 possible causes for ASD: genetics (75.8%), child’s brain structure (59.7%), will of God (46.3%), and toxins found in vaccines/immunizations (41.8%). Disagreement was espoused by the largest percentages (52.2—93.9%) for all remaining possible causes (e.g., germ/virus, my partner’s age, stress at birth), with the exception of “environmental pollution,” which was espoused in relatively equal proportions (37.4% = agree; 28.4% = neutral; 34.3% = disagree). Results regarding ASD-onset patterns and their potential associations with beliefs about causes for ASD are forthcoming.
Conclusions: Most parents disagreed with a greater number of potential causes than agreed with them (16 vs. 4 causes). A larger proportion espoused vaccines as causing ASD than in prior work (~42% vs. 33%). This is surprising, given that the SSC was marketed largely as a genetic-factors study of ASD. Additional findings regarding prevalence of ASD-onset types in the SSC and their relations to etiological beliefs about ASD will be discussed.
See more of: Clinical Phenotype
See more of: Symptoms, Diagnosis & Phenotype