Aims: The aim of this study is to investigate differences in HSPA8 polymorphisms between first-episode psychotic (FEP) schizophrenic patients and healthy participants after adjustment for temperamental personality traits.

Main methods: This study included fifty drug-naive schizophrenic patients with an FEP and fifty healthy participants who served as controls. Genotyping of HSPA8 polymorphisms was performed in patients and healthy subjects as well. Personality characteristics were assessed using the standardized Greek version of the Alternative Five-Factor Zuckerman-Kuhlman Personality Questionnaire (ZKPQ).

Key findings: Our results showed that FEP patients presented a polymorphism differentiation related to the HSPA8 gene (rs1136141), and a higher frequency of T carriers compared to healthy controls was observed. The HSP8A polymorphism and the levels of Neuroticism as measured by the Alternative Five-Factor ZKPQ were the variables most closely and independently associated with FEP in multiple logistic regression analysis, and the odds of being assessed with a FEP was 2.8 times greater in T carriers compared to non-carriers.

Significance: Present findings indicate a role of HSP8A in FEP and underline the importance of including personality traits in the study of the factors associated with the development of schizophrenia.