BACKGROUND:

Obsessions and compulsions may occur in the post-streptococcal disorders Sydenham's chorea and paediatric autoimmune neuropsychiatric disorders associated with streptococcus (PANDAS). The proposed mediators are anti-basal ganglia antibodies (ABGA).

AIMS:

We tested the hypothesis that post-streptococcal autoimmunity may have a role in'idiopathic'obsessive-compulsive disorder (OCD).

METHOD:

We examined 50 children with OCD for ABGA using enzyme-linked immunosorbent assay (ELISA) and western immunoblotting. The findings were compared with paediatric autoimmune (n=50), neurological (n=100) and streptococcal (n=40) controls.

RESULTS:

The mean ABGA binding on ABGA binding on ELISA was elevated in the patient cohort compared with all control groups (P<0.005 in all comparisons). Western immunoblotting revealed positive antibody binding (as seen in Sydenham's chorea) in 42% of the patient cohort compared with 2-10% of control groups (P<0.001 in all comparisons).

CONCLUSIONS:

Our findings support the hypothesis that central nervous system autoimmunity may have a role in a significant subgroup of cases of OCD. Further study is required to examine whether the antibodies concerned are pathogenic.