Infections like rubella, herpes simplex virus (HSV), cytomegalovirus (CMV), Toxoplasma gondii are known to disrupt fetal neural development. T.gondii is an intracellular protozoan parasite which infects around one-third of the human population. It resides encysted in the brain of immunocompetent hosts. Infection can be contracted from meat containing tissue cysts,raw fruits, vegetables, soil, and contaminated water. Association between T.Gondii and Schizophrenia is well studied and a meta analysis (Torrey et al., 2007) reported 2.73 fold increase in overall odds of T. gondii seropositivity for schizophrenia.
Nora Hamdani and colleagues investigated the relationship between this infection and bipolar disorder in a case-control sero-prevalence study involving 110 BD patients (Community ) and 106 healthy controls living in France. Immunoassay methods were used to measure IgG and IgM class antibodies to T. gondii in blood sample.
None of the BD patients was in an acute phase of T. gondii infection as IgM antibodies detection was negative for the whole sample. The sero positivity to T. gondii was significantly higher in BD patients as compared to controls (76.9% vs. 48.2%; p = 0.00045). Sero-positive participants had a 3.6 fold odds of having BD as compared to sero-negative patients (OR=3.6, 95%CI=1.93– 6.75, p o0.0001). Higher levels of IL-6 was seen among BD patients as compared to controls (independent of serological status of T. gondii infection).
Conclusion: Results are similar to two previous studies, an Ethiopian study (Tedla, 2011: OR 3) and a North-American study (Pearce, 2012: OR of 2.3 ) suggesting a strong link between infection and bipolar disorders.
Psychotropic drugs have different levels of anti-Toxoplasma activity. Sodium valproate, have therapeutic indices equivalent to that of trimethoprim on protozoal activity. Fluphenazine and thioridazine have relevant anti-Toxoplasma activity. Adequate treatment of infection by T. gondii was reported to improve the efficacy of antidepressant treatment. Authors hope that this line of thinking might open up further options for future research.
Summary of the article:
Relationship between Toxoplasma gondii infection and bipolar disorder in a French sample. Hamdani N, Daban-Huard C, Lajnef M, Richard JR, Delavest M, Godin O, Guen EL, Vederine FE, Lépine JP, Jamain S, Houenou J, Corvoisier PL, Aoki M, Moins-Teisserenc H, Charron D, Krishnamoorthy R, Yolken R, Dickerson F, Tamouza R, Leboyer M. J Affect Disord. 2013 Jun;148(2-3):444-8.