Gene‐environment interaction between the brain‐derived neurotrophic factor Val66Met polymorphism, psychosocial stress and dietary intake in early psychosis

Aim The brain‐derived neurotrophic factor (BDNF) is a major participant in the regulation of food intake and may play a role in the regulation of the stress response. We aimed to investigate whether there is a gene‐environment interaction in the relationship between stress and BDNF Val66Met polymorphism in relation to dietary patterns in a sample of subjects with early psychosis. Methods We studied 124 early psychotic disorder (PD) patients, 36 At‐Risk Mental States (ARMS) and 62 healthy subjects (HS). Dietary patterns were examined by a dietician. Physical activity, life stress and perceived stress were assessed by validated questionnaires. BDNF Val66Met polymorphism (rs6265) was genotyped. A gene‐environment interaction was tested with multiple linear regression analysis while adjusting for covariates. Results Perceived stress was not associated with calorie intake in HS. In ARMS subjects, Met‐carriers who presented low‐perceived stress were associated with increased caloric intake. Conversely, those who presented high‐perceived stress were associated with reduced caloric intake. In PD, perceived stress was neither associated with increased calorie intake without an effect by BDNF genotype nor a gene‐environment interaction. Perceived stress was associated with food craving in PD patients, independent of genotype, and in ARMS or HS who were Val homozygous. Conclusions This study suggests that the common Val66Met polymorphism of the BDNF gene may modulate the relationship between life stress and calorie intake in subjects at risk for psychosis.