Dependence has both physical and psychological components. Physical dependence refers to the body’s physiological adaption due to continuous use of the drug. Over time, the body will develop a tolerance to the drug, causing withdrawal symptoms to arise when use is abruptly discontinued. Psychological dependence is a state of mind that influences the user to continuously use the drug, or the belief or perception that the user needs the drug to function.  Both physical and psychological dependence are highly influential in continued use or relapse. An individual may continue drug use to avoid withdrawal symptoms (physical dependence), or to experience euphoria, satisfaction, or pleasure (psychological dependence).