Drug abuse refers to the systematic use of drugs for pleasure (rather than medical) reasons.
To be classified as as a disorder it has to have most of the following characteristics:-
- It results in physical, mental, and/or emotional harm to the abuser and/or the people in the abusers life,
- The user requires increasing dosages to achieve the same kind of "high,"
- Such a significant portion of the abuser's time is dedicated to thinking, using, and acquiring drugs that their life becomes impacted.
 Users not addicted
A "chipper" (when it's not a machine for shredding old Christmas trees) is a person who uses many different drugs while avoiding addiction to any specific one. Chippers may, for example, smoke pot on a daily basis, but use "harder" drugs less often enough that they don't become addicts.  Chippers may be at risk of becoming addicts.
 Drugs subject to abuse
Virtually every drug can be abused, though some are much more harmful than others, and some are relatively harmless but extremely addictive. Alcohol, amphetamines, barbiturates, caffeine, nicotine and opiates are by far the most widely used drugs.
The Health Officers Council of British Columbia released a study in 2005 entitled A Public Health Approach To Drug Control in Canada, which studied the effects of drugs on Canucks. Well, it is assumed everybody knows that all the French-loving arctic hippies do is smoke weed and act "commie".
 The war on drugs
It has been argued that the War on Drugs has actually increased rates of drug abuse, as was seen during the alcohol prohibition era. Since usage is pushed into back alleys there are no checks on usage, purity, restriction of sales.
It is also an extremely expensive system to maintain, from the cops policing the drugs, the court system and the jail to hold people for a crime that ultimately harms no one but themselves -- assuming it even harms them. The cost per day to keep a drug user in jail varies from 50-300 dollars a day. Money that could probably be better spent in education and rehab.
But it looks good for politicians and makes our private prison system lots of profit.