The association between Toxoplasma gondii seropositivity and respectively Bipolar Disorder (BD) and Schizophrenia/Schizoaffective disorder (SZ) is one of the most studied link between one pathogen and psychiatric disorders. The aim of the present study was thus to retrospectively determine if the administration of an antipsychotic and/or a mood stabilizer having known in vitro Anti-Toxoplasmic Activity (TATA+) was associated with a better clinical outcome in a population of 152 BD or 114 SZ patients and seropositive for T. gondii infection compared to patients receiving a treatment without anti-toxoplasmic activity (TATA-).
This multicenter study was conducted in an academic public hospital during a 3-years period between 2009 and 2011. All consecutive inpatients and outpatients with SZ or BD diagnosis with a stable treatment for more than 4 weeks were recruited. socio-demographic and clinical characteristics measured with validated scales as well as a serological status for toxoplasmic infection were included. Treatments were classified according to their in vitro antitoxoplasmic activity. A multivariate model was used to determine the clinical characteristics that were significantly different between patients receiving a treatment with no antitoxoplasmic activity compared to others.
BD patients with positive serum antibodies against T. gondii presented more lifetime depressive episodes (p=0.048) after adjustment for age, sex and sociodemographic characteristics when treated by drug having no anti-toxo activity, compared to patients having received drugs with anti-toxo activity. A significant difference was not found in BD toxonegative patients and in SZ toxopositive or toxonegative patients.
It seems to be of importance to consider prescribing a drug with a clear anti-toxoplasmic activity (TATA+) for BD patients seropositive to T. gondii, in particular valproate that was found as the mood stabilizer with the highest antitoxoplasmic activity. Prospective randomized controlled trials are warranted to confirm this preliminary data.