Relationship of food allergy with quality of life and sleep in psychiatric patients

Aim Few studies have examined the relationship between food allergy (FA) and psychiatric disorders. We aimed to examine the possible relationship of FA with quality of life (QOL) and sleep in adult patients with psychiatric disorders. Methods Of the 812 participants (451 females, mean age: 42.7 ± 11.3 years), 430 had schizophrenia/schizoaffective disorder, 106 had depression, 124 had bipolar disorder, 40 had anxiety disorders, 38 had developmental disorders, and 11 had eating disorders; 63 were other cases. We documented FA and sleep disturbance via a questionnaire. QOL was assessed with the Medical Outcomes Study 8‐Item Short‐Form Health Survey (SF‐8 Japanese version). Results There were 126 patients (15.5%) reporting FA. SF‐8 physical component summary (PCS) and mental component summary (MCS) scores were both significantly lower among individuals with FA than those without. Moreover, PCS and MCS scores decreased as the number of allergens increased. Sleep disturbance was common among patients (76.0%). The proportions of individuals with sleep disturbance and nocturnal awakening were significantly higher in the group with FA, with the proportions increasing with higher number of allergens. Conclusion We obtained the first evidence that FA is associated with impaired QOL and sleep in psychiatric patients, which can be improved by avoiding exposure to food allergens. Food allergy was found to be associated with poorer quality of life mentally as well as physically. Food allergy was also associated with sleep disturbance, nocturnal awakening, in particular. The associations became stronger as the number of food allergens increased.