JUN 10, 2024 7:00 AM PDT

Cat Scratch Bacteria Linked to Higher Incidence of Psychosis

WRITTEN BY: Annie Lennon

Adults with psychosis are three times more likely to have Bartonella DNA in their blood than those without. The findings suggest that vector-borne pathogens like Bartonella could play a role in various mental health conditions. The corresponding study was published in Frontiers in Psychiatry

Cat scratch disease (CSD), also known as Bartonellosis, is a bacterial infection caused by Bartonella henselae. Most infections occur following scratches from domestic or feral cats. Of at least 45 different Bartonella species, 18 are known to infect humans. Improved methods for detecting Bartonella infection have led to diagnoses of Bartonelloses in some patients with psychiatric symptoms. 

In the current study, researchers investigated whether exposure to or infection with Bartonella is linked to psychosis. To do so, they recruited 116 participants, including 29 controls without psychosis, 16 who had symptoms but had not received a formal diagnosis, 7 children or adolescents with psychosis, 44 adults with psychosis, and 20 relatives or a participant with psychosis. 

Ultimately, the researchers found that 43.2% of adults with psychosis had Bartonella DNA in their bloodstream, compared to 14.3% of adult controls. From further tests, the researchers were able to identify which Bartonella species was present in 18 of the 31 participants with Bartonella in their blood. A majority—11 out of 18—had Bartonella henselae. 

“This study provides further support for an association between Bartonella species infection and psychosis and may have important clinical implications,” said study author Dr. Brian Fallon, Professor at Columbia University Irving Medical Center, in a press release, “However, it is worth emphasizing that association does not prove causality; other factors may account for the association.”

“The other significant finding was that the frequency of positive antibody tests for Bartonella infection was not significantly different for the controls versus the individuals with psychosis; this suggests that exposure to Bartonella is common in the general population and that reliance on serologic test results alone can be misleading,” he concluded. 


Sources: Neuroscience News, Frontiers in Psychiatry

About the Author
Bachelor's (BA/BS/Other)
Annie Lennon is a writer whose work also appears in Medical News Today, Psych Central, Psychology Today, and other outlets.
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