At this time, theories about the cause(s) of BDD are speculative. Most likely there are multiple factors, including biological, psychological and sociocultural, that contribute to its etiology. Neurochemical factors, such as abnormalities in the brain chemical serotonin, may make some people more likely to express the symptoms of BDD. However, psychological factors such as teasing about one's appearance during childhood, family's or peers' emphasis on appearance or trauma or sexual abuse might also be risk factors for the expression of symptoms. Finally, media messages about appearance might worsen the condition in some vulnerable individuals with BDD.