Estimations of the number people with mental diseases associated with toxoplasmosis and identification of risk factors by continent

Strong evidence exists based on metanalysis of the relationship between toxoplasmosis and many psychiatric diseases: schizophrenia, bipolar disorder, and suicidal behavior. Herein, we estimate the number of cases based on the attributable fraction due to toxoplasmosis on these diseases. The population attributable fraction of mental disease associated with toxoplasmosis was 20,4% for schizophrenia; 27,3% for bipolar disorder; and 0,29% for suicidal behavior (self-harm). The lower and upper estimated number of people with mental disease associated with toxoplasmosis was 4 ' 816.491 and 5 ' 564.407 for schizophrenia; 6 ' 348.946 and 7 ' 510.118,82 for bipolar disorder; and 24.310 and 28.151 for self-harm; for a global total lower estimated number of 11 ' 189.748 and global total upper estimated number of 13 ' 102.678 people with mental disease associated with toxoplas-mosis for the year 2019. According to the prediction through the Bayesian model of risk factors for toxoplasmosis associated with mental disease, these varied in importance geographically; thus, in Africa, the most important risk factor was water contamination and in the European region, the cooking conditions of meats. Toxoplasmosis and mental health should be a research priority given the enormous potential impact of reducing this parasite in the general population.

Automated summary

There is strong evidence from meta-analysis indicating a relationship between toxoplasmosis and various psychiatric diseases including schizophrenia, bipolar disorder, and suicidal behavior. This study estimates the number of cases by assessing the attributable fraction of these diseases due to toxoplasmosis. The population attributable fraction for mental diseases associated with toxoplasmosis is 20.4% for schizophrenia, 27.3% for bipolar disorder, and 0.29% for suicidal behavior. The estimated number of individuals with mental diseases associated with toxoplasmosis ranges from 4,816,491 to 5,564,407 for schizophrenia, 6,348,946 to 7,510,118.82 for bipolar disorder, and 24,310 to 28,151 for self-harm. Globally, the lower estimated number is 11,189,748 and the upper estimated number is 13,102,678 for the year 2019. Geographic variations in the importance of risk factors for toxoplasmosis associated with mental diseases are observed, with water contamination being the most important risk factor in Africa and cooking conditions of meats being important in the European region. Given the potential impact of reducing this parasite on the general population, toxoplasmosis and mental health should be a research priority.