Genetic: Numerous studies have been undertaken that show a possible genetic predisposition toward eating disorders.
Biochemical:Eating behavior is a complex process controlled by the neuroendocrine system. Abnormalities within the neuroendocrine system such as irregularities in the manufacture, amount or transmission of certain neurotransmitters, hormones or neuropeptides may adversely affect eating behavior.
o serotonin: a neurotransmitter involved in depression also has an inhibitory affect on eating behavior
o norepinephrine is both a neurotransmitter and an hormone; abnormalities in either capacity may affect eating behavior
o dopamine:which in addition to being a precursor of norepinephrine and epinephrine is also a neurotransmitter which regulates the rewarding property of food
Hypothalumus-pituatary-adrenal-axis (HPA axis):Part of the neuroendocrine system which is responsible for the manufacture of adrenaline and cortisol. Dysregulation of the HPA-axis has been associated with eating disorders.
Immune System: studies have shown that a majority of patients with anorexia and bulimia nervosa have elevated levels of autoantibodies that affect hormones and neuropeptides that regulate appetite control and the stress response. There may be a direct correlation between autoantibody levels and associated psychological traits.
Lesions: studies have shown that lesions to the right frontal lobe or temporal lobe can cause the pathological symptoms of an eating disorder.
Tumors: tumors in various regions of the brain have been implicated in the development of abnormal eating patterns.
brain calcificaton: a study highlights a case in which prior calcification of the right thalumus may have contributed to development of anorexia nervosa.
Obstetric complications. There have been studies done which show obstetric and perinatal complications such as maternal anemia, very pre-term birth (32<wks.), being born small for gestational age and sustaining a cephalhematoma at birth increase the risk factor for developing either anorexia nervosa or bulimia nervosa.