This finding suggests that cannabis withdrawal symptoms are partly influenced by familial (possibly including genetic) factors not overlapping with heritability of use and heavy use of cannabis. Furthermore, using a family-based sample, Ehlers et al. (2010) found a heritability of 26% for experiencing cannabis withdrawal symptoms. However, their sample was ascertained for alcoholism making the results less generalizable, they took a genomic variance components approach to compute heritability which can be less robust than the classical twin design, and their measure of cannabis withdrawal did not include all DSM-5 symptoms.
