Low-Density Lipoprotein Cholesterol Is a Possible Blood Biomarker of Schizoid Personality Traits among Females

Lower serum levels of low-density lipoprotein cholesterol (LDL-C) have been suggested to indicate higher suicide risk and various psychiatric symptoms. Previously, we reported that lower serum LDL-C levels are associated with loneliness, social phobia, isolated life with little social support, and lower trust in others among young non-clinical females. Thus, we hypothesize that schizoid personality traits may be associated with lower serum LDL-C. We here verified this hypothesis using non-clinical data and clinical data with schizophrenia. Using the database from the Midlife in Japan (MIDJA), a cohort of residents living in Tokyo, we analyzed whether schizoid-related interpersonal characteristics were associated with LDL-C. In addition, we assessed the association between blood biomarkers including LDL-C and schizoid personality traits in 101 adult non-clinical volunteers. Finally, we evaluated the interaction between LDL-C and social decision making of patients with schizophrenia. In female non-clinical volunteers, serum LDL-C level was a predictive factor and negatively correlated with schizoid personality traits. Female patients with schizophrenia, whose serum LDL-C levels were lower, tended not to trust other females. The present findings suggest that LDL-C may influence schizoid personality traits in females, which provide a basis for further investigation into the biological aspects of schizoid personality disorder.