Drug Misuse- refers to the use of a drug for purposes for which it was not attended or using a drug in excessive quantities.
Drug abuse is the use of illicit drugs, or the abuse of prescription or over-the-counter drugs. The abuse of legitimate drugs (prescription or over-the-counter) can happen when people use the drugs in a manner or in quantities other than directed, or for purposes that are not legitimate. See also drug abuse first aid and drug abuse and dependence.
The misuse and abuse of prescription drugs is a big problem in today's society. While the difference between the two is slight, the thin line between drug misuse and drug abuse can make a big difference in the degree of danger you are facing if you engage in either.Read more: Drug Misuse Vs. Drug Abuse | eHow.com
Withdrawal- Discontinuation of the use of an addictive substance. The symptoms of withdrawal include headache, diarrhea, and tremors and can range from mild to life threatening, depending on the extent of the body's reliance on the addictive substance
Addiction is characteried by the presence of tolerance (needing more and more of the drug to achieve the same effect) Drug addiction is a state of physical or psychological dependence on a drug.
Physical dependency refers to a state resulting from chronic use of a drug that has produced tolerance and where negative physical symptomsof withdrawal result from abrupt discontinuation or dosage reduction. Physical dependence can develop from low-dose therapeutic use of certain medications and antidepressants, as well as misuse of recreational drugs- wikipedia
Physiological dependency compulsive use of a substance despite significant problems resulting from such use. Although tolerance and withdrawal were previously defined a s necessary and sufficient for dependence, they are currently only two of several possible criteria.