Addiction is a chronic disorder with biological, psychological, social and environmental factors influencing its development and maintenance. About half the risk for addiction is genetic. Genes affect the degree of reward that individuals experience when initially using a substance (e.g., drugs) or engaging in certain behaviors (e.g., gambling), as well as the way the body processes alcohol or other drugs. Heightened desire to re-experience use of the substance or behavior, potentially influenced by psychological (e.g., stress, history of trauma), social (e.g., family or friends’ use of a substance), and environmental factors (e.g., accessibility of a substance, low cost) can lead to regular use/exposure, with chronic use/exposure leading to brain changes.
These brain changes include alterations in cortical (pre-frontal cortex) and sub-cortical (limbic system) regions involving the neuro-circuitry of reward, motivation, memory, impulse control and judgment. This can lead to dramatic increases in cravings for a drug or activity, as well as impairments in the ability to successfully regulate this impulse, despite the knowledge and experience of many consequences related to the addictive behavior.