According to MedlinePlus, a medical information resource established by the U.S. National Library of Medicine, drug abuse is defined as the use of illegal drugs or the misuse of prescribed or over-the-counter medication for at least a year, with negative consequences. Drugs available by prescription are often abused, and the ones most often abused are pain-relieving drugs that contain opiates. Excessive drug use can lead to physical dependence and addiction.
The Limbic System
The "Clinical Textbook of Addictive Disorders" explains that the reward pathway targeted by drugs of abuse is known in as the limbic system. This brain pathway serves to motivate activities that are vital to survival and well-being by providing feelings of pleasure and reward in response to such activity. A rewarding activity or drug of abuse stimulates a region of the brain called the ventral tegmental area, or VTA. Activation of these neurons then triggers the release of the chemical neurotransmitter dopamine in another area of the brain known as the nucleus accumbens. Dopamine release is interpreted in the brain as pleasurable.
Conditioned Associations
When the limbic system is activated and a person experiences feelings of reward, the brain makes note of the environmental conditions that were associated with the pleasurable situation, explains the "Clinical Textbook of Addictive Disorders." These memories are called conditioned associations and might include the people who were present, the location of the activity's occurrence, ambient lighting, background music and so on. A drug abuser might experience intense drug craving in response to conditioned associations.
Tolerance
When a drug is abused over a long period, the brain and the body are able to make adjustments that allow for normal functioning despite the presence of the drug, explains the "Clinical Manual of Addiction Psychopharmacology." Because of these physiological adaptations, the euphoric feelings sought by a drug abuser require higher doses of the drug. Additionally, because the drug abuser's physiologic condition has been altered, unpleasant withdrawal symptoms accompany drug abstinence. This is known as physical dependence.
Addiction
Chronic drug abuse can lead to drug addiction. Addiction is characterized by the compulsive use of and intense craving for drugs, according to the "Clinical Textbook of Addictive Disorders." The National Institute on Drug Abuse explains that long-term drug abuse changes the brain's structure and function such that decision-making and self-control are impaired. Meanwhile, an addicted individual experiences intense urges to use drugs, despite negative consequences.
Treatment
The Mayo Clinic explains that treatment for drug abuse usually consists of a combination of different therapies, such as detoxification, medication, counseling and support groups. Psychological treatments aim to help drug users to develop coping mechanisms to handle drug cravings and prevent relapse. If you think you may be suffering from a drug abuse problem, talk to your health care provider about getting help.
References
- MedLinePlus: Drug Abuse
- "Clinical Textbook of Addictive Disorders (Third Edition)"; Richard J. Frances et al.; 2005
- "Clinical Manual of Addiction Psychopharmacology"; Henry R. Kranzler, M.D. and Domenic A. Ciraulo, M.D.; 2005
- The Mayo Clinic: Drug Addiction
