The difference in susceptibility to addiction is considered to be related to genetic influences. Very few people are able to return to occasional use after becoming addicted. Patients with a substance use disorder often begin taking a substance to achieve a desirable pharmacologic effect. When the drug use is continued to relieve personal problems or used as a coping mechanism, dependence may develop. When the individual becomes dependent on the drug, a genetically associated psychological mechanism leads to an alteration of the brain function. This is a feature of central nervous system (CNS) drugs that leads to addiction.
Genetic factors significantly contribute, approximately 50%, to the likelihood that an individual will develop an addiction. Environmental factors, cultural influences and resilient behaviors learned by the individual impact the extent to which genetic factors exert their influence.1
Other factors that may contribute to the genetic expression of addiction include:1