The results showed that the heritability of AN was 0.56 in the narrow DSM-IV criteria and 0.31 in the narrow criteria general DSM-IV. The narrow criteria were the full DSM-IV criteria, while the broad criteria were the full DSM-IV criteria, excluding amenorrhea. This distinction is particularly interesting because the current DSM-V no longer requires amenorrhea to meet all diagnostic criteria. Study result shows that heritability can have a significant impact on the development of anorexia.