The relationship between Toxoplasma gondii IgG antibodies and generalized anxiety disorder and obsessive-compulsive disorder in children and adolescents: a new approach.

Aim: Toxoplasma gondii may play a role in the development of psychiatric diseases by affecting the brain. The purpose of this study was to examine the relation between serum toxoplasma IgG positivity and obsessive-compulsive disorder (OCD) and generalized anxiety disorder (GAD) in children and adolescents.

Method: Sixty patients diagnosed with OCD and 60 patients with GAD presenting to the pediatric psychiatry clinic, together with 60 control group subjects with no psychiatric diagnosis, were included in the study. The patients were administered the State-Trait Anxiety Inventory for Children and the Children's Yale-Brown Obsessive Compulsive Scale. Serum toxoplasma IgG levels were determined from blood specimens collected from the study and control groups. The results were then compared using statistical methods.

Results: State and trait anxiety levels were significantly higher in the OCD and GAD patients than in the control group (p = .0001/.0001). Serum toxoplasma IgG levels were positive in 21 (35%) of the OCD patients, 19 (31.7%) of the GAD patients and 6 (10%) of the control group. A significant relation was determined between IgG positivity and GAD (p = .003). IgG-positive individuals were determined to have a 4.171-fold greater risk of GAD compared to those without positivity (4.171[1.529-11.378]) (p = .005). A significant relation was also determined between IgG positivity and OCD (p = .001). IgG-positive individuals were determined to have a 4.846-fold greater risk of OCD compared to those without positivity (4.846[1.789-13.126]) (p = .002).

Conclusion: This study shows that serum toxoplasma IgG positivity indicating previous toxoplasma infection increased the risk of GAD 4.171-fold and the risk of OCD 4.846-fold in children and adolescents. Further studies are now needed to investigate the relation between T. gondii infection and GAD/OCD and to determine the pathophysiology involved.