Key Takeaway:
- A 2023 review of 17 studies found that cat ownership risk was linked to a higher likelihood of schizophrenia-related disorders.
- Researchers reported that people exposed to cats had roughly twice the odds of developing schizophrenia-related conditions.
- The evidence does not prove causation, and scientists say larger, higher-quality studies are needed to confirm the link.
A review of 17 studies conducted across 11 countries found that cat ownership risk is linked to a higher likelihood of schizophrenia-related disorders. However, researchers emphasize that more rigorous studies are needed to determine whether this relationship is truly causal.
Review Finds Significant Association Across Studies
Researchers at the Queensland Center for Mental Health Research analyzed studies published over the past 44 years and reported a significant association between cat ownership and schizophrenia-related conditions.
The 2023 review, led by psychiatrist John McGrath, examined research from countries including the United States and the United Kingdom. After reviewing the evidence, the team found that people exposed to cats had approximately twice the odds of developing schizophrenia-related disorders compared with those who were not exposed.
“Our review provides support for an association between cat ownership and schizophrenia-related disorders,” the authors wrote in the study.
The theory of cat ownership risk in relation to schizophrenia dates back to 1995, when researchers proposed that exposure to the parasite Toxoplasma gondii could be a contributing factor.
Researchers Examine Possible Role of Parasites
T. gondii reproduces in cats and can spread to humans through contact with infected cat feces, contaminated water, or undercooked meat.
Health experts estimate that about 40 million people in the United States carry the parasite, often without symptoms. Researchers have found that T. gondii can enter the central nervous system and may influence neurotransmitters involved in brain function.
Previous studies have linked the parasite to personality changes, psychotic symptoms, and neurological disorders, including schizophrenia. However, researchers caution that an association does not prove the parasite causes these conditions or that the infection originated from cats.
Some studies included in the review suggested that childhood exposure to cats may increase the likelihood of developing schizophrenia later in life. Others found no meaningful connection.
Study Limitations Leave Questions Unanswered
The researchers emphasized that the available evidence has significant limitations.
Fifteen of the 17 studies reviewed used a case-control design, which can identify associations but cannot establish cause and effect. Several studies were also rated as low quality.
“There is a need for more high-quality studies in this field,” the authors wrote.
Results varied widely across studies. One study reported no significant link between cat ownership risk before age 13 and schizophrenia, but it did identify an association when focusing specifically on exposure between ages nine and 12.
Another U.S. study involving 354 psychology students found no connection between cat ownership and schizotypy, a measure of traits associated with schizophrenia. However, participants who reported cat bites scored higher on those measures than those who had not been bitten.
A separate study found that cat bites were associated with elevated scores on tests measuring unusual psychological experiences. Researchers suggested that other pathogens, including Pasteurella multocida, could play a role.
McGrath and his colleagues said larger and more representative studies are needed before firm conclusions can be drawn.
The authors noted that future research should clarify whether cat ownership risk is a genuine factor that modifies the likelihood of mental disorders, or if the observed association is better explained by other environmental and biological influences.
Visit Healthcare 360 Magazine For The Most Recent Information.
