There is no single cause for alcoholism. Alcoholism can run in families, but a person's emotions, physical health and upbringing also play a role in the development of this disease. Chemical Dependency Drug abuse occurs when someone takes any drug for purposes other than for what the drug was intended or in a manner or quantity other than directed. This includes use of drugs that are considered illegal or used illegally, as well as prescription drugs. A drug addiction is the compulsive and continued use of a drug, or the loss of control over its use, despite the consequences.
Drug dependence has both psychological and physical characteristics.
If unable to obtain the drug, the person who is addicted may experience symptoms of distress or withdrawal and a need or craving to take the drug again. Signs of chemical dependency vary with the type of drug and the person abusing the drug. Some signs of chemical dependency include unpredictable behavior, such as being agitated one minute and lethargic the next. Some addicted people have difficulty sleeping, while others sleep for long periods of time. Those abusing drugs also often lose interest in eating, have dazed or expressionless eyes, flushed skin and a runny nose.