Clinic Notes: Obsessive-Compulsive Disorder (OCD) and the Immune System

Children with OCD are sometimes misdiagnosed with autism. Children with autism do perseverate, line up toys, and like to have their environment a certain way. They also do not like change, will do better on a strict schedule, and often engage in repetitious, self-stimulatory behavior. But usually they have the other symptoms that are not seen in the child with OCD. Low serotonin levels are implicated in both disorders and often both are treated with medications that increase serotonin levels although the improvement, if any, is usually small. A recent study in mice links OCD to problems in the immune system. It was already known that PANDAS, an abbreviation for Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections, causes OCD in a subset of children and worsens tics in children with Tourette's Syndrome. Children with autism often have more infections than normally developing children and this has led to the hypothesis that autism could be an immune disorder. At this point the evidence for this hypothesis in not compelling, but wouldn't it be interesting if autism turns out to be an immunity problem.