Like diabetes cancer and heart disease, addiction is caused by a combination of behavioral environmental and biological factors. Genetic risks factors account for about half of the likelihood that an individual will develop addiction. The consequences of untreated addiction often include other physical and mental health disorders that require medical attention if left untreated over time. Addiction becomes more severe disabling and life threatening. How substance use changes the Brain? People feel pleasure when basic needs such as hunger, thirst and sex are satisfied. In most cases these feelings of pleasure are caused by the release of certain chemicals in the brain. Most addictive substances cause the brain to release high levels of these same chemicals that are associated with pleasure or reward. Over time ,continued release of these chemicals causes changes in the brain systems involved in reward motivation and memory .when these changes occur a person may need the