Obsessions in children with autism or Asperger's Syndrome: Content analysis in terms of core domains of cognition

Baron-Cohen, S. and Wheelwright, S. (1999) British Journal of Psychiatry, 175, 484-490.

We report a survey of the content of obsessions in children with autism spectrum conditions. We use the term obsessions narrowly, to indicate strong, repetitive interests. We predicted that obsessions would not cluster randomly, but rather would occur significantly more often in the domain of ‘folk physics’ (an interest in how things work), and significantly less often in the domain of ‘folk psychology’ (an interest in how people work).

Results: Both predictions were confirmed.

There is no evidence that in autism the obsession is distressing or unwanted ego-dystonic. In the present study we asked parents to report on the content of their child’s obsessions, with the aim of establishing a taxonomy of obsessions in autism spectrum conditions.

Sample: Group 1 comprised 92 parents of children with autism (n=50), Asperger syndrome (n=32), or autism spectrum (n=10). Group 2 comprised 33 parents of children with Tourette syndrome, seven of whom had comorbid attention-deficit hyperactivity disorder (ADHD) and nine of whom had obsessional behaviours.

The obsessional interests in autism are wholly different from the neurotic obsessionality seen in patients with OCD. For example, a child with autism may have an obsessional collection of names and types of lizard, or an obsessional collection of meteorites. In contrast, a patient with OCD may have checking obsessions (e.g. a need to check the gas taps repeatedly) or washing obsessions (an excessive need to get rid of germs on their hands or clothes). Hence, whereas the patient with OCD has obsessions that typically involve fears of danger and harm, and unwanted thoughts that are ego-dystonic and intrusive, and which the patient tries to get rid of through performing compulsions, people with autism spectrum conditions typically follow their interests or hobbies to an extreme and narrow degree, to that they come experts in their chosen field.