Are anorexia nervosa and bulimia nervosa separate disorders?
GROUND: Anorexia nervosa (AN) and bulimia nervosa (BN) are classified as separate and distinct clinical disorders. Recently, there has been support for a transdiagnostic theory of eating disorders, which would reclassify them as one disorder. OBJECTIVE: To determine whether AN and BN are a single disorder with one cause or separate disorders with different causes. METHOD: Hill’s Criteria of Causation were used to test the hypothesis that AN and BN are one disorder with a single cause. Hill’s Criteria of Causation demand that the minimal conditions are needed to establish a causal relationship between two items which include all of the following: strength of association, consistency, temporality, biological gradient, plausibility, coherence, experimental evidence and analogy. RESULTS: The hypothesis that AN and BN have a single cause did not meet all of Hill’s Criteria of Causation. Strength of association, plausibility, analogy and some experimental evidence were met, but not consisten
