When a regular user stops taking the drug, the body experiences the physiological trauma known as withdrawal. Psychological dependence occurs when taking drugs becomes the center of the user's life. Psychological dependence on drugs can destroy ties to family and friends, as well as cause the user to abandon outside interests, values, and goals. The user goes from taking drugs to feel good, to taking them to keep from feeling bad. Over time, drug use itself heightens the bad feelings and can leave the user suicidal.
Drugs can remain in the body long after use has stopped.
The extent to which a drug is retained in the body depends on the drug's chemical composition. Such accumulations of drugs and their slow release over time may have effects on the mind and body weeks or even months after drug use has stopped. Drugs can interfere with memory, sensation, and perception. They distort experiences and cause a loss of self-control that can lead users to harm themselves and others. Drugs interfere with the brain's ability to take in, sort, and synthesize information.