Drug Abuse

"Drug abuse is the use of illegal drugs, or the misuse of prescription or over-the-counter drugs for at least a year with negative consequences".¹

http://www.parentfurther.com/sites/default/files/images/Drugs.jpg?1300484605

Drug: is a chemical that alters the functioning of living tissues². Drugs can be used medically to improve health of an individual. However, when drugs are used in excessive amounts for non medical purposes, this is called drug abuse³. Some prescription drugs may be abused, such as tranquilizers (e.g. valium=addictive), antibiotics (overuse for minor infections), steroids (e.g. hormones used as performance enhancers by athletes), or even caffeine.

Reference 

1. http://www.nlm.nih.gov/medlineplus/ency/article/001945.htm

2. Anne Tindale, Biology: A concise revision course for CXC. Stanley Thornes (Publishers) Ltd.

3. Caribbean Examination Council. Biology, Resource for teachers. Book 5