While a genetic overlap between social behaviors and addictive processes may explain the phenotypic overlap, specific biological mechanisms have not been elucidated. However, many intriguing lines of evidence exist. For example, it is possible that “narcotic addiction operates partially through mechanisms which ensured mammalian social bonding over the course of evolution” (46), as supported, for instance, by involvement of the opioid system in separation distress. It has also been noted (4) that illicit drug abuse, a common behavioral attribute in deviant social groups, may be part of the repertoire of affiliative and reproductive behavior consistent with Zahavi's handicap principle (47), where potentially socially disabling (e.g., resulting in imprisonment) behavioral/personality characteristics convey a fitness benefit in a deviant group and provide group protection. Drug abuse is also associated with insecure attachment (48,49) and can be a key for transition from parental to (delinquent) peer affiliation influence.
