Schizophrenia and spp. Infection: A Pilot Case-Control Study.

Recently, infections with emerging zoonotic bacteria of the genus have been reported in association with a range of central nervous system (CNS) symptoms. Currently, it remains unknown if spp. infection is associated with symptoms of schizophrenia/schizoaffective disorder (SCZ/SAD). The objective of this study was to determine if there is an association between species infection and SCZ/SAD. A secondary objective was to determine if SCZ/SAD symptoms were more severe among participants with documented spp. infection. Using a case-control study design, 17 cases and 13 controls were evaluated with a series of clinical and cognitive assessments. Blood samples were collected and tested for spp. infection using serological, microbiological, and molecular techniques. People with SCZ/SAD were more likely than healthy volunteers to have spp. DNA in their bloodstream, with 11 of 17 cases (65%) positive by spp. droplet digital PCR (ddPCR). In comparison, only one healthy volunteer was spp. ddPCR positive (8%,  = 0.0024). Based on serology, spp. exposure was common among people with SCZ/SAD (12 of 17) as well as among healthy volunteers (12 of 13), with no significant difference between the groups ( = 0.196). Within the case group of people with SCZ/SAD, there was no significant difference in SCZ/SAD severity scores between people with and without ddPCR evidence of spp. infection. This pilot study provides preliminary evidence in support of future investigations that should examine a potential contribution of spp. infection to SCZ/SAD.