The causes of orthorexia nervosa are not known and are likely complex in nature. Predisposing factors might include genetics, a family or personal history of dieting or disordered/restrictive eating, personality traits (e.g., perfectionism, impulsivity, health anxiety, low self-esteem), mental disorders (e.g., OCD), problematic social media use, or a history of being bullied.[1][2][3][4][5]
Ultimately, more research specific to orthorexia nervosa is needed to better understand its causes.