Positive and negative schizotypy personality traits are lower in individuals on ketogenic diet in a non-clinical sample

Schizotypal personality comprises traits such as odd beliefs, perceptual abnormalities, and social difficulties; these traits are distributed throughout the general population. While not meeting the clinical threshold for schizophrenia or schizotypal personality disorder, schizotypal personality traits still provide insights for understanding early clinical risk factors. Ketogenic diet reportedly reduces psychotic symptoms in preclinical and clinical studies. Therefore, we investigated whether ketogenic diet is associated with lower schizotypal traits in the general population. Participants following a ketogenic or other diet were recruited using opportunity sampling. Individuals completed a survey investigating general demographic, socioeconomic, health, diet and lifestyle questions, followed by the Schizotypal Personality Questionnaire - Brief Revised version (SPQ-BR). We found that individuals following a ketogenic diet (n = 118) had lower ideas of reference, magical thinking, suspiciousness, unusual perceptions, constricted affect, social anxiety scores, cognitive (positive) perceptual scores, interpersonal (negative) scores and total SPQ-BR compared to individuals on the other diets (n = 139). Magical thinking, constricted affect, social anxiety, cognitive perceptual, interpersonal scores and total SPQ-BR scores remained significant when we controlled for body mass index (BMI) and age. Disorganised features were not influenced by ketogenic diet. The longer individuals adhered to a ketogenic diet the lower their positive and negative schizotypy traits. These findings highlight that ketogenic diet is associated with lower non-clinical schizotypal personality traits. Our results suggest that ketogenic diet might have potential prophylactic properties for individuals at-risk for psychosis.