Disease Model of Addiction

The disease model of addiction describes an addiction as a lifelong disease involving biologic and environmental sources of origin. The traditional medical model of disease requires only that an abnormal condition be present that causes discomfort, dysfunction, or distress to the individual afflicted. The contemporary medical model attributes addiction, in part, to changes in the brain's mesolimbic pathway. The medical model also takes into consideration that such disease may be the result of other biologic, psychologic, or sociologic entities despite an incomplete understanding of the mechanisms of these entities.

Within the disease model of addiction, a genetic predisposition is believed to be present. An environmental event is also felt likely to be required. These hypotheses would explain the result of adoption and twin studies that have been carried out, indicating that twins separated at birth have a higher likelihood of concordance for addictive disease than would be expected were there not a genetic component, and indicating that these twins have a lower likelihood of concordance for addictive disease than do twins who remain together in identical environments.