Substances of abuse affect cognition in a number of ways.One of its indirect effects include craving, which has been an important factor to relapse to substance abuse.Peer-induced craving is a powerful form of this construct.The brain mechanisms involved in drug craving or the urge have been studied in recent years.As the social contagion and wrong association in peer groups are the main causes to substance abuse and relapse, understanding the mechanisms involved in processing a peers thought and behavior will be beneficial in the rehabilitation treatment.This literature review highlights the short-term neurotoxieity of drugs of abuse and its long-term consequence of cognitive deficits in the brain and mind of abusers, including adults, adolescences and prenatal exposure of drugs of abuse, as well as the genetic factors associated.The review also provides a window into complex social-cognitive relations in which drug abusers not only try to think of what the other abusers are thinking or behaving, but also attempt to measure and seek craving responses to external and internal related stimuli-i.e.why and what the others craving reaction affect ones thoughts and behaviors.