Family and twin studies suggest modest but significant heritability of FA in different age groups. Analysis of familial transmission using 27 families with EEG available from both parents and at least two offspring showed a significant correlation of r=.46 between mean parent and offspring values, which is a proxy measure for heritability, with the assumption that familial resemblance arises from genetic, rather than environmental commonality of family members (Anokhin and Rohrbaugh, 1998). This study also showed a significant familial association between FA and comorbid depression and alcoholism. However, generalizability of this study may be limited because the sample included families selected for high incidence of alcoholism, along with control families.
