Addiction is a chronic disorder with biological, psychological, social and environmental factors influencing its development and maintenance. Typically, it falls under two categories, substance dependence, or drug addiction, and behavioral addiction such as a gambling addiction. 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.