In The Politics of Autism, I write:
Autism often involves a range of other co-occurring conditions: intellectual disabilities (e.g., low IQ); delays in gross motor skills (e.g., walking, throwing) and fine motor skills (e.g., writing); attention problems and hyperactivity; anxiety; self-injurious behavior; unusual sensitivity to certain sounds, smells, or feelings; extreme food selectivity; and sleep disorders. For autistic people and their families, the co-occurring conditions may cause as much anguish as the autism itself.
G.N. Soke and colleagues have an article at The Journal of Autism and Developmental Disorders titled "Prevalence of Co-occurring Medical and Behavioral Conditions/Symptoms Among 4- and 8-Year-Old Children with Autism Spectrum Disorder in Selected Areas of the United States in 2010."
We compared the prevalence of various medical and behavioral co-occurring conditions/symptoms between 4- and 8-year-olds with autism spectrum disorder (ASD) from five sites in the Autism and Developmental Disabilities Monitoring Network during the 2010 survey year, accounting for sociodemographic differences. Over 95% of children had at least one co-occurring condition/symptom. Overall, the prevalence was higher in 8- than 4-year-olds for 67% of co-occurring conditions/symptoms examined. Further, our data suggested that co-occurring conditions/symptoms increased or decreased the age at which children were first evaluated for ASD. Similarly, among the 8-year-olds, the prevalence of most co-occurring conditions/symptoms was higher in children with a previous ASD diagnosis documented in their records. These findings are informative for understanding and screening co-occurring conditions/symptoms in ASD.
From the article:
[F]indings from this study are informative and useful to policymakers, clinicians, and earlyintervention specialists. These data may inform policymakers on the type of screening programs that may provide the best opportunity to capture most co-occurring conditions/symptoms during routine evaluations of children with ASD. Since co-occurring conditions can be found even at a young age, clinicians may use these data to support screening for co-occurring conditions/symptoms and provide specific interventions. As reported by others, the high prevalence and the diversity of co-occurring conditions/symptoms in ASD suggest the need for a comprehensive system of care for these children. Assessment of co-occurring conditions/symptoms at an early age may provide opportunity for early identification of children with ASD, since these conditions/symptoms increase the likelihood to be in contact with different health care providers.