The stigma of drug addiction and crime. Alcoholism and addiction have been classified as medical illnesses by the American Medical Association since the 1950s. The distinction has done little to treat addiction as a disease rather than as a moral defect or a criminal matter. There is a definitive link between crime and drug addictions that primarily contributes to the illegal status of commonly abused drugs.
Not only is it illegal to carry many of these drugs, but lowering a person's inhibitions when under the influence can encourage them to commit other crimes. The types of crimes a person can commit when using drugs are broad and depend on a variety of sub-factors, but regardless, drug users are more likely than non-users to commit crimes. Petty theft to obtain drugs and satisfy their cravings when they are desperate is another way drugs influence people to commit crimes. Whether the person affected is addicted to illegal drugs or prescription drugs, the effect on their life can be disastrous.
In addition to the many health problems that come with drug addiction, there are many other areas of a person's life that will be adversely affected. It's hard to maintain healthy relationships with other people when drug addiction has taken hold. While it's easy to see how funding an illegal drug addiction would affect a person's finances, it's a different situation for those who are addicted to prescription drugs, at least at first. It may not be immediately obvious why drug addiction is a social problem, but it is estimated that, for every person with an addiction, another five are adversely affected, and they are not always the people closest to the addict.
The most permanent effect of drug addiction is death, which is more likely due to addiction due to the increase in tolerance that leads to overdose.