"According to the National Institute on Drug Abuse, the three classes of prescription drugs that are often abused include:
Opioids used to treat pain. Central nervous system (CNS) depressants, such as benzodiazepines (Xanax, Valium, Ativan, Klonopin), used to treat anxiety and sleep disorders."
And medical professionals are prone to dole them out willy nilly at the least provocation. Opioids effect the brain even with the first dosage. And the longer you are on them the more likely you will be addicted like this lovely high school teenager in the article above, who turned into a hard-core heroin addict after a knee injury.
Then of course when the behaviour becomes irrational on the drugs, the psychiatrists start making a living by giving mental illness labels to these same people and prescribe a whole slew of different drugs and it all just becomes a vicious cycle.
The drug companies initially convinced the doctors to try these drugs on their patients saying they were harmless, which they turned out not to be but instead were highly addictive. Big Pharma is out to make a buck and they don't care about the harm done.
"Prescription drug abuse causes the largest percentage of deaths from drug overdosing. Of the 22,400 drug overdose deaths in the US in 2005, opioid painkillers were the most commonly found drug, accounting for 38.2% of these deaths." - (drugfreeworld.org)
When someone is in pain you don't prescribe the hard core drug first to a young patient who has never taken drugs unless a Drug Company offers to buy you a new car for trying them and you are an un-ethical GP. And it turns out doctors see it as a right to work this way and not a moral or ethical issue. If you a moral doc, you prescribe the milder, non-addictive stuff first.