Toxoplasma gondii infection and chronic schizophrenia: is there any association?

Abstract

Background: Toxoplasma gondii (T. gondii) infection has been identified as a risk factor for schizophrenia. Objectives: Herein, we sought to evaluate the association between T. gondii infection and clinical symptoms and quality of life in patients with schizophrenia. Methods: We conducted a cross-sectional study with 48 patients with chronic schizophrenia and 40 controls. Peripheral blood was drawn, and IgM and IgG anti-T. gondii antibodies were evaluated by Enzyme-Linked Immunosorbent Assay (ELISA). Depressive, positive and negative symptoms were assessed, respectively, by the Calgary Depression Scale (CDS) and the Positive and Negative Syndrome Scale (PANSS). Cognitive performance was assessed in patients by the Brazilian version of the Schizophrenia Cognition Rating Scale (SCoRS-BR). Quality of life was assessed by the Brazilian version of the Quality of Life in Schizophrenia scale (QLS-BR). Results: The prevalence and titers of T. gondii IgM and IgG antibodies did not differ between patients and controls. The positive serology for T. gondii IgG antibodies was not associated with illness symptoms, cognitive performance, depressive symptoms or quality of life. Discussion: Our findings suggest that toxoplasmosis infection is not associated with severity of symptoms, quality of life, cognitive or depressive symptoms in schizophrenia patients.

Effects of Toxoplasma gondii infection on cognition, symptoms, and response to digital cognitive training in schizophrenia

“…Studies indicate a relationship between startle latency response and IgG titers in schizophrenia subjects and healthy controls 23 , and that toxoplasmosis in men with schizophrenia may lead to more severe negative and cognitive symptoms and a less favorable course of the disorder compared to non-infected male subjects 24 . But many studies did not find a significant relationship between seropositivity and cognitive impairment in schizophrenia 25 – 27 . Additionally, a birth cohort found a positive association between T. gondii infection and the prevalence of mental disorders, but not specifically schizophrenia 28 .…”

Association between exposure to toxoplasmosis and major psychiatric disorders: a systematic review

“…One of them, a cross-sectional study that assessed the serological status of 48 patients with schizophrenia and 40 healthy controls, found similar seroprevalence and titers for both IgG and immunoglobulin M anti- T. gondii antibodies in both groups. 19 Another study, on the other hand, compared 34 patients with schizophrenia and 85 healthy controls, finding a seropositivity prevalence of 91.18% (95%CI 77.04-96.95) among the patients, compared to 70.59% (95%CI 60.18-79.21) among controls. The difference was considered significant (p = 0.017).…”

“…In fact, in these studies the majority of patients were being treated with psychotropics such as carbamazepine, lithium, and olanzapine and were in the chronic stage of their respective disorders. 11,19,21,26 In addition, a recently published French cohort study 52 showed that treatments with anti-toxoplasmic activity were associated with a lower volume of depressive symptoms (aOR = 0.8 [95%CI 0.7-0.9]; p = 0.01), as well as with lower rates of chronic peripheral inflammation (20.9 vs. 48.6%; aOR = 3.5 [95%CI 1.5-7.9]; p = 0.003). This is consistent with the findings of a cross-sectional study on the same drugs.…”

“…In fact, in these studies the majority of patients were being treated with psychotropics such as carbamazepine, lithium, and olanzapine and were in the chronic stage of their respective disorders. 11 , 19 , 21 , 26 …”

“…Patients diagnosed with schizoaffective or schizophreniform disorders were excluded, and both age and the type and dosage of psychotropic drugs used in treatment were controlled for. The seroprevalence was significantly higher in patient group (OR = 2.55; 95% confidence interval [95%CI] 1.59-4.09; p = 0.00001), as was the serum concentration of antibodies (71.3 6 81 international unit Alipour 18 6 Campos-Carli 19 7 Alvarado-Esquivel 20 7 Emelia 21 6 Ansari-Lari 22 9…”