Please forward this error screen to 66. Classic hallmarks of addiction include impaired control psychopharmacology drugs the brain and behavior 2nd edition pdf substances or behavior, preoccupation with substance or behavior, and continued use despite consequences. Addiction is the compulsive use of a substance or performance of a behavior that is independent of withdrawal. Similarly, shopping and playing videogames are associated with compulsive behaviors in humans and have also been shown to activate the mesolimbic pathway and other parts of the reward system.
There are a range of genetic and environmental risk factors for developing an addiction that vary across the population. Roughly half of an individual’s risk for developing an addiction is derived from genetics, while the other half is derived from the environment. In other words, anyone can become an addict under the right circumstances. Similar rates of heritability for other types of drug addiction have been indicated by other studies. Knestler hypothesized in 1964 that a gene or group of genes might contribute to predisposition to addiction in several ways.
For example, altered levels of a normal protein due to environmental factors could then change the structure or functioning of specific brain neurons during development. These altered brain neurons could change the susceptibility of an individual to an initial drug use experience. In support of this hypothesis, animal studies have shown that environmental factors such as stress can affect an animal’s genotype. Overall, the data implicating specific genes in the development of drug addiction is mixed for most genes. One reason for this may be that the case is due to a focus of current research on common variants.