Association between schizophrenia and syphilis: a retrospective study in Xiamen, China

Previous studies have shown that patients with mental illnesses such as schizophrenia have a higher risk for syphilis infection. However, the clinical characteristics of psychotic patients who are infected with syphilis remain unknown. The aim of this study was to investigate the prevalence of syphilis in psychotic patients in Xiamen and to compare the social function and serum biochemical markers between schizophrenia patients with and without syphilis.

There were a total of 1586 psychotic patients screened for syphilis from May 2016 to August 2017 in Xiamen Mental Health Center. We retrospectively studied 87 schizophrenia patients in this study. The NOSIE-30 score and serum biochemical markers were analyzed for all schizophrenia patients.

The seroprevalence of syphilis was 3.3% (52/1586) in our study. Schizophrenia patients infected with syphilis (SCZ-S) showed a higher irritability score compared with patients without syphilis (SCZ-C) (p < 0.05). Similarly, the serum CK, CK-MB, K and Cl values were significantly higher in the SCZ-S group than in the SCZ-C group (P < 0.05). In addition, the CK levels in SCZ-S drug-free patients were significantly higher than in drug-free patients in the SCZ-C group (P < 0.05).

The seroprevalence of syphilis was 3.3% (52/1586) in our study, which revealed that psychotic patients were at high risk of being infected with Treponema pallidum. In addition, schizophrenia patients infected with syphilis can be more irritable and could have disrupted electrolyte and CK and CK-MB levels.