Toxoplasma gondii and other risk factors for schizophrenia: an update.

The failure to find genes of major effect in schizophrenia has refocused attention on nongenetic, including infectious factors. In a previous study, antibodies to Toxoplasma gondii were found to be elevated in 23 studies of schizophrenia (OR 2.73; 95% CI 2.10-3.60). The current study replicates this finding with 15 additional studies (OR 2.71; 95% CI 1.93-3.80) and compares this with other identified schizophrenia risk factors. The highest risk factors are having an affected mother (relative risks [RR] 9.31; 95% CI 7.24-11.96), father (RR 7.20; 95% CI 5.10-10.16), or sibling (RR 6.99; 95% CI 5.38-9.08) or being the offspring of immigrants from selected countries (RR 4.5; 95% CI 1.5-13.1). Intermediate risk factors, in addition to infection with T. gondii, include being an immigrant from and to selected countries (RR 2.7; 95% CI 2.3-3.2), being born in (RR 2.24; 95% CI 1.92-2.61) or raised in (RR 2.75; 95% CI 2.31-3.28) an urban area, cannabis use (OR 2.10-2.93; 95% CI 1.08-6.13), having minor physical anomalies (OR 2.23; 95% CI 1.42-3.58), or having a father 55 or older (OR 2.21-5.92; 95% CI 1.46-17.02). Low-risk factors include a history of traumatic brain injury (OR 1.65; 95% CI 1.17-2.32), sex abuse in childhood (OR 1.46; 95% CI 0.84-2.52), obstetrical complications (OR 1.29-1.38; 95% CI 1.00-1.84), having a father 45 or older (OR 1.21-1.66; 95% CI 1.09-2.01), specific genetic polymorphisms (OR 1.09-1.24; 95% CI 1.06-1.45), birth seasonality (OR 1.07-1.95; 95% CI 1.05-2.91), maternal exposure to influenza (RR 1.05; 95% CI 0.98-1.12), or prenatal stress (RR 0.98-1.00; 95% CI 0.85-1.16).

[1]  Xiao-Guang Chen,et al.  Analysis of the antibodies anti-Toxoplasma gondii by ELISA based on two diagnostic antigens: rSAG1 and rBAG1 , 2011, Acta Parasitologica.

[2]  K. Laurens,et al.  A systematic meta-review grading the evidence for non-genetic risk factors and putative antecedents of schizophrenia , 2011, Schizophrenia Research.

[3]  D. Rujescu,et al.  GWA study data mining and independent replication identify cardiomyopathy-associated 5 (CMYA5) as a risk gene for schizophrenia , 2011, Molecular Psychiatry.

[4]  M. Cannon,et al.  Is traumatic brain injury a risk factor for schizophrenia? A meta-analysis of case-controlled population-based studies. , 2011, Schizophrenia bulletin.

[5]  M. Järvelin,et al.  Meta-analysis of paternal age and schizophrenia risk in male versus female offspring. , 2011, Schizophrenia bulletin.

[6]  T. Shibre,et al.  Serum antibodies to Toxoplasma gondii and Herpesvidae family viruses in individuals with schizophrenia and bipolar disorder: a case-control study. , 2011, Ethiopian medical journal.

[7]  J. Dubey,et al.  Toxoplasma gondii infection and schizophrenia: a case control study in a low Toxoplasma seroprevalence Mexican population. , 2011, Parasitology international.

[8]  Chunyu Liu,et al.  After GWAS: searching for genetic risk for schizophrenia and bipolar disorder. , 2011, The American journal of psychiatry.

[9]  A. Daryani,et al.  Serological survey of Toxoplasma gondii in schizophrenia patients referred to Psychiatric Hospital, Sari City, Iran. , 2010, Tropical biomedicine.

[10]  S. Alavi,et al.  Toxoplasma gondii infection in first-episode and inpatient individuals with schizophrenia. , 2010, International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases.

[11]  R. Seime,et al.  Sexual abuse and lifetime diagnosis of psychiatric disorders: systematic review and meta-analysis. , 2010, Mayo Clinic proceedings.

[12]  A. Dirican,et al.  The role of latent toxoplasmosis in the aetiopathogenesis of schizophrenia--the risk factor or an indication of a contact with cat? , 2010, Folia parasitologica.

[13]  Gerty J. L. M. Lensvelt-Mulders,et al.  SCHIZOPHRENIA AND 1957 PANDEMIC OF INFLUENZA: META-ANALYSIS , 2010, Schizophrenia Research.

[14]  O. Koru,et al.  Possible role of toxoplasmosis in patients with first-episode schizophrenia* , 2010, Turkish Journal of Medical Sciences.

[15]  Tyrone D. Cannon,et al.  Paternal age as a risk factor for schizophrenia: How important is it? , 2009, Schizophrenia Research.

[16]  Pall I. Olason,et al.  Common variants conferring risk of schizophrenia , 2009, Nature.

[17]  H. Hashemi,et al.  Relation Between Toxoplasma Gondii Infections and Schizophrenia , 2009 .

[18]  John W. Pinney,et al.  A Unique Dual Activity Amino Acid Hydroxylase in Toxoplasma gondii , 2009, PloS one.

[19]  F. Dogruman-Al,et al.  A possible relationship between Toxoplasma gondii and schizophrenia: A seroprevalence study , 2009, International journal of psychiatry in clinical practice.

[20]  Elliot S. Gershon,et al.  Genetic associations with schizophrenia: Meta-analyses of 12 candidate genes , 2008, Schizophrenia Research.

[21]  John P A Ioannidis,et al.  Systematic meta-analyses and field synopsis of genetic association studies in schizophrenia: the SzGene database , 2008, Nature Genetics.

[22]  A. Aker,et al.  The schizophrenia and Toxoplasma gondii connection: Infectious, immune or both? , 2008, Advances in therapy.

[23]  R. Yolken,et al.  Are some cases of psychosis caused by microbial agents? A review of the evidence , 2008, Molecular Psychiatry.

[24]  Peter B. Jones,et al.  Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review , 2007, The Lancet.

[25]  O. Geçici,et al.  Anti-Toxoplasma gondii antibodies in patients with schizophrenia--preliminary findings in a Turkish sample. , 2007, Schizophrenia bulletin.

[26]  R. Yolken,et al.  Antibodies to Toxoplasma gondii in patients with schizophrenia: a meta-analysis. , 2007, Schizophrenia bulletin.

[27]  R. Schwarcz,et al.  Toxoplasma gondii and schizophrenia: linkage through astrocyte-derived kynurenic acid? , 2007, Schizophrenia bulletin.

[28]  D. Hinze‐Selch,et al.  A controlled prospective study of toxoplasma gondii infection in individuals with schizophrenia: beyond seroprevalence. , 2007, Schizophrenia bulletin.

[29]  B. Maher,et al.  Minor physical anomalies in schizophrenia: A meta-analysis , 2007, Schizophrenia Research.

[30]  P. Gorwood,et al.  Paternal ages below or above 35 years old are associated with a different risk of schizophrenia in the offspring , 2007, European Psychiatry.

[31]  S. Lawrie,et al.  Cannabis as a risk factor for psychosis: systematic review , 2005, Journal of psychopharmacology.

[32]  Ronnie Driver,et al.  Biostatistics: a Methodology for the Health Sciences , 2005 .

[33]  R. Buchanan,et al.  Summer birth and deficit schizophrenia: a pooled analysis from 6 countries. , 2004, Archives of general psychiatry.

[34]  R. Kahn,et al.  No relationship between risk of schizophrenia and prenatal exposure to stress during the Six-Day War or Yom Kippur War in Israel , 2003, Schizophrenia Research.

[35]  H. Möller,et al.  Summer birth and deficit schizophrenia. , 2003, The American journal of psychiatry.

[36]  Peter B. Jones,et al.  Obstetric complications and schizophrenia: historical and meta-analytic review. , 2002, The American journal of psychiatry.

[37]  P. Mortensen,et al.  Evidence of a dose-response relationship between urbanicity during upbringing and schizophrenia risk. , 2001, Archives of general psychiatry.

[38]  P. Andersen,et al.  Effects of family history and place and season of birth on the risk of schizophrenia. , 1999, The New England journal of medicine.

[39]  E. Cantor-Graae,et al.  Schizophrenia and migration: a meta-analysis and review. , 2005, The American journal of psychiatry.

[40]  J. van os,et al.  The environment and schizophrenia: the role of cannabis use. , 2005, Schizophrenia bulletin.

[41]  H. Shatat,et al.  Seropositivity of toxoplasmosis in patients with schizophrenia. , 2005, The Journal of the Egyptian Public Health Association.

[42]  E. Torrey,et al.  A systematic review and meta-analysis of Northern Hemisphere season of birth studies in schizophrenia. , 2003, Schizophrenia bulletin.

[43]  Xu Shi-e.  Contrast study on schizophrenia's toxoplasmosis infection rate , 2003 .

[44]  R. Murray,et al.  Schizophrenia and complications of pregnancy and labor: an individual patient data meta-analysis. , 1999, Schizophrenia bulletin.