With respect to the cholinergic system as a third potential neurochemical
system involved in Internet-use disorders, Montag et al. (2012)
reported a link between a genetic variation of the CHRNA4 gene
(linked to the cholinergic nicotine/acetylcholine receptor) and
Internet-use-disorder features. However, these studies have typically
involved relatively small, incompletely characterized samples
and analyses targeted to specific candidate polymorphisms. In
summary, although several initial studies give preliminary evidence
for potential genetic contributions to Internet-use disorders,
further research is needed (including from genome-wide association
studies).