Association Between Childhood Exposure to Pet Cats and Later Diagnosis of Schizophrenia: A Case-Control Study in Saudi Arabia

There is an increasing number of reports suggesting an effect of adverse environmental factors during vulnerable periods of prenatal and perinatal development in the etiology of schizophrenia. Cat-transmitted infections, especially Toxoplasma gondii, are possible risk factors for the later development of schizophrenia. We conducted a case-control study to examine childhood cat ownership in 78 patients with schizophrenia (cases), 78 outpatients with depression and anxiety disorders (control group one), and 78 outpatients with no psychiatric history (control group two). Cat ownership before the age of 13 was reported by 52.6%, 44.9%, and 24.4% of patients in cases, control group one, and control group two, respectively. Compared with non-psychiatric patients, patients with schizophrenia were 3.4 times more likely to report owning cats in their childhood (odds ratio (OR)=3.441; p=0.000; 95% confidence interval (CI)=1.740-6.804). Compared with both control groups, the likelihood of owning a cat as a child was 2.1 times more among cases (OR=2.093; p=0.008; 95% CI=1.203-3.640). Age, female gender, and family history appeared to be positively associated with cat ownership and schizophrenia. This study supports the evidence of a relationship between childhood exposure to pet cats and the later development of schizophrenia. Further in-depth research is needed to clarify the relationship between exposure to pet cats in childhood and later diagnosis of schizophrenia, adjusting for potential confounders.