delusions – Toxoplasma gondii & Human Phenotype

Latent toxoplasma infection in real-world schizophrenia: Results from the national FACE-SZ cohort

February 12, 2018
Fond,G., Boyer, L. ,Schurhoff, F. ., Berna,F. , Godin, O., Bulzacka, E., Andrianarisoa, M. Brunel, ,L. ,Aouizerate, B. , Capdevielle, D.,Chereau, I. , Coulon, N., D'Amato, T. , Dubertret,C. , Dubreucq, J.,Faget, C.,. Lancon, Leignier,S., Mallet,J., Misdrahi, D., Passerieux, C., Rey,R., Schandrin,A., Urbach,M., Vidailhet,P., Llorca, P. M., Leboyer, M., Grp,F.S.
Schizophrenia Research 2018; 201: 373-380

Click for abstract

Objective: Latent Toxoplasma infection has been associated with widespread brain immune activation, increased blood brain barrier permeability, neural disruption, increased dopamine release in dopaminergic neurons, with NMDA activation and with schizophrenia (SZ) onset risk. Toxoplasma has been suggested to be a source of chronic low-grade inflammation and this inflammation has been associated with cognitive impairment in SZ. The objective of the present study were (i) to determine if latent Toxoplasma infection was associated with specific clinical features in stabilized SZ subjects, with cognitive impairment and with increased low-grade peripheral inflammation and (ii) to determine if Treatments with Anti-Toxoplasmic Activity (TATA) were associated with improved outcomes in subjects with latent Toxoplasma infection. Methods: A comprehensive 2 daylong clinical and neuropsychological battery was administered in 250 SZ subjects included between 2015 and 2017 in the national FondaMental Expert Center (FACE-SZ) Cohort. Solid phase-enzyme microplate immunoassay methods were used to measure IgG class of antibodies to T. gondii in blood sample. Latent Toxoplasma infection was defined by T. gondii IgG ratio >= 0.8, equivalent to >= 10 international units. Chronic peripheral inflammation was defined by highly sensitive Creactive protein blood level >= 3 mg/L. Results: Latent Toxoplasma infection has been found in 184 (73.6%) of this national multicentric sample. In the multivariate analyses, latent Toxoplasma infection has been significantly associated with higher PANSS negative (aOR = 1.1 [1.1-1.1], p = 0.04) and excitement subscores (aOR = 1.3 [1.1-1.6], p = 0.01), with two specific symptoms (i.e., reference delusion (aOR = 3.6 [1.2-10.6] p = 0.01) and alogia (aOR = 16.7 [2.0-134.7], p = 0.008)) and with chronic low-grade peripheral inflammation (27.2% vs. 7.6%, aOR = 3.8 [1.4-10.3], p = 0.004). Extrapyramidal symptoms remained significantly associated with latent Toxoplasma infection. On the opposite, no significant association of latent Toxoplasma infection with age, gender, age at SZ onset, suicide behavior or cognitive deficits has been found in these models (all p > 0.05). TATA were associated with lower depressive symptoms (aOR = 0.8[0.7-0.9], p = 0.01), and with lower rates of chronic peripheral inflammation (20.9% vs. 48.6%, aOR = 3.5 [1.5-7.9], p = 0.003) but not with higher cognitive scores (p > 0.05). Conclusion: The present findings suggest that Toxoplasma is almost 3 times more frequent in SZ population compared to general population in France. The potential cerebral underpinnings of the association of latent Toxoplasma infection and the above-mentioned outcomes have been discussed. Future studies should confirm that TATA may be effective to reduce Toxoplasma-associated depressive symptoms and low-grade peripheral inflammation.

The association between Toxoplasma and the psychosis continuum in a general population setting

October 2, 2017
Lindgren, M., Torniainen-Holm, M., Yolken, R., Suvisaari, J.
Schizophrenia Bulletin 2017; 43: S108-S109

Click for abstract

Background: An increased prevalence of antibodies to Toxoplasma gondii has been found to be associated with psychosis. An association with positive symptom severity in a psychosis risk sample has also been reported. However, the possible association between toxoplasma and positive symptoms in the general population is unknown. Methods: We investigated whether Toxoplasma gondii is associated with psychosis diagnoses and psychotic symptoms in the general population. We used data from Health 2000, a large health survey of the Finnish population aged 30 and older (n = 5906). Levels of IgG antibodies to Toxoplasma gondii were determined and seropositivity defined as a cutoff of 50 IU/ml. Lifetime psychotic symptoms were identified with section G of the Composite International Diagnostic Interview, Munich version (M-CIDI). The CIDI screen was considered positive if the interviewee reported any clinically relevant symptom or at least 3 symptoms regardless of clinical relevance. Lifetime psychotic disorders were screened from the sample and were diagnosed with DSM-IV using case notes and SCID-I interview. The possible diagnoses were: any psychotic disorder, functional psychosis, schizophrenia, other nonaffective psychosis, and affective psychosis. Results: The seroprevalence of Toxoplasma in the population was 13%; 12% of the participants reported at least one psychotic symptom, the most common symptoms being delusions of reference and suspicion, and 4% were considered positive for the CIDI screen. In a logistic regression model, toxoplasma seropositivity was the only significant predictor of the CIDI screen status, when other variables associated with toxoplasma were adjusted for (age, gender, education, region of residence, cat ownership, and C-reactive protein measuring inflammation). Toxoplasma infection was not associated with any psychosis diagnoses. Conclusion: In a large sample representing the whole Finnish population aged 30 and older, we found that toxoplasma infection predicted psychotic symptoms but not psychosis diagnoses. The association between psychotic symptoms and toxoplasma was not explained by inflammation.