Regression in Children with ASD: Associations with Parents' Beliefs about Causes of ASD

Background: Parent-reported developmental regression occurs in an average of one-third of children with autism spectrum disorder (ASD). While prospective, clinician-rated studies detect higher rates of skill losses, understanding parent perception of this phenomenon is valuable, as it may subsequently color parents’ thoughts about ASD and decisions they make on behalf of their families. Limited data suggest that parents who observed regression in their children were significantly more likely to believe that external factors—most often vaccines—caused ASD (Goin-Kochel & Myers, 2005). Fears about immunizations causing autism is now one of the leading reasons behind a growing trend of delayed or refused vaccine uptake (Offit, 2008), which has important public-health ramifications (e.g., increased disease outbreaks). Understanding more about how regression shapes parents’ beliefs and actions is key to developing targeted education efforts.

Objectives: (a) To provide descriptive information about regression status across three related samples; (b) To assess parents' degree-of-agreement with various potential causes of ASD; and (c) To determine whether child history of regression is associated with beliefs about causes of ASD.

Methods: Data were analyzed for children with ASD (probands; N=2758; M age=9 years, SD=3.6 years, range=4—17.9 years) who participated in the Simons Simplex Collection (SSC). Regression was defined according to the Autism Diagnostic Interview—Revised (ADI-R), with rates of language and social-skill losses calculated for the full SSC sample; SSC probands from the Baylor College of Medicine (BCM) site (n=203); and a subset of BCM probands who were recontacted for additional data collection (n=68), including parents' beliefs about causes of ASD via the Revised Illness Perception Questionnaire (IPQ-R; Moss-Morris, et al., 2002). Frequencies of agreement/disagreement with possible ASD etiologies were calculated for the IPQ-R's 21 closed-ended items about potential causes. Qualitative analyses were used to categorize parents’ open-ended rankings of their top three beliefs about causes of ASD. ANOVA’s were conducted to determine whether parents’ degree-of-agreement with various etiologies differed according to their child’s regression status.

Results: Regression rates were only slightly higher in the BCM samples: full SSC=29.5%, full BCM=34%, recontacted BCM=35.3%. The five causes that families most frequently endorsed were genetics (75.8%), child’s brain structure (59.7%), will of God (46.3%), toxins found in vaccines (41.8%), and environmental pollution (37.4%). Parent-provided causes were organized into 10 categories, with genetics/heredity being first-ranked among the largest proportion of parents (42.6%); however, external factors were ranked (i.e., 1^st, 2^nd, or 3^rd) by nearly 84% of families as causing ASD. Parents who reported regression in their children were more likely to agree with “toxins in vaccines” (F[1,66]=3.74, p=.05) and “environmental pollution”  (F[1,66]=3.25, p=.07) as causes.

Conclusions: Findings support an association between parent-reported regression in children with ASD and parental endorsement of vaccines/external mechanisms as causing autism, even within this small subsample. That so many also endorsed “will of God” may reflect potential geographical and/or cultural differences within the BCM subsample. Replication of this study at other SSC sites will elucidate varying belief patterns by locale for targeted education efforts.