Victims of a reward deficiency syndrome? The brain reward centers of people who develop substance use disorders may be inadequately activated by events in life—a problem called the reward deficiency syndrome. With the colors red and orange indicating more brain activity, these PET scans show that before abusers of cocaine, methamphetamine, and alcohol use drugs, their reward centers (right) are generally less active than the reward centers of nonabusers (left) (Volkow et al., 2004, 2002).