Researchers at Columbia University have published a study that suggests a link between childhood-onset OCD and strep infections.  The study, published in Molecular Psychiatry (August 11, 2009), shows a link between the antibodies produced in response to strep infections, and the development of both OCD and tics commonly seen in Tourette’s Syndrome.

This study furthers earlier research that led to the conceptualization of a specific subtype of OCD called PANDAS, which stands for pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections.  Initial research in the 1990’s came about as a result of reports that some children were experiencing severe, sudden-onset OCD and tics after having gotten ill with strep throats.  In these cases, a child would go to bed one night feeling perfectly healthy, and wake up the next morning with strep throat and severe OCD and tics.  When these cases were treated with antibiotics for the strep infection, the OCD and tic symptoms dramatically diminished.

The original theorizing and research on PANDAS was conducted by Susan Swedo, MD at the National Institute for Mental Health (NIMH).  Swedo and her team of researchers found that these kids with strep and OCD also had hightened levels of strep antibodies.  This led to their theorizing that the antibodies were possibly causing neurological changes that led to the rapid onset of OCD and tic symptoms.  Then, in 2000, Swedo and her colleagues published research that showed these children had swelling in the basal ganglia of their brains similar to the swelling seen when brains are attacked by the body’s immune system in other diseases.

In the latest study, researchers gave mice immunizations with inactivated strep bacteria (much like human immunizations, which are also based on inactivated forms of specific bacteria).  These mice developed compulsive, repetitive behaviors similar to those seen in human OCD.  The key point here is that the mice were not exposed to live strep, but merely to the immunization, which in turn led to the production of antibodies (which is the purpose of an immunization), and to the appearance of OCD symptoms.

Researchers then injected antibodies from these mice into other, non-immunized mice.  This second group of mice also developed OCD-like symptoms.  Put together, this research shows that it is the antibodies that cause the OCD-like symptoms in these mice, which supports Swedo’s earlier theorizing that it is the antibodies that are causing the PANDAS OCD.

So it appears that in some cases, childhood-onset OCD can be caused by the immune system doing its job of creating antibodies to fight strep infection.  This contributes to a growing body of research that indicates that OCD has its origins in neurological / biological pathology, be it bacteria or genetics.

•Tom Corboy, MFT, is the director of the OCD Center of Los Angeles, a private, outpatient clinic specializing in Cognitive-Behavioral Therapy (CBT) for the treatment of Obsessive-Compulsive Disorder (OCD) and related conditions.  In addition to individual therapy, the center offers six weekly therapy groups, as well as online therapy, telephone therapy, and intensive outpatient treatment.  To contact the OCD Center of Los Angeles, click here.