In 1972, The National Commission on Marijuana and Drug Abuse did the most comprehensive study to date, called Marijuana, A Signal of Misunderstanding. This study, commissioned by Congress, found that moderate marijuana smoking presents no significant risk to the user or to society, and recommended that the country "decriminalize" minor marijuana offenses; i.e., that penalties be removed for personal use and possession. So far, only 11 states have decriminalized marijuana, and the federal government shows no sign of following suit.
In Amsterdam, The Netherlands, after a short rise, use by young people actually went down after that country decriminalized marijuana.
Testimony of R. Keith Stroup, Esq before the Subcommittee on Crime Judiciary Committee 3/6/96 :
A 1993 Rand Corporation study that compared drug use in states that had decriminalized marijuana versus those that had not, found that where marijuana was more available -- the states that had decriminalized -- hard drug abuse as measured by emergency room episodes decreased. In short, what science and actual experience tell us is that marijuana tends to substitute for the much more dangerous hard drugs like alcohol, cocaine, and heroin.
An economic analysis of the effects of decriminalization of marijuana usage found that states that had reduced penalties for marijuana possession experienced a rise in marijuana use and a decline in alcohol use with the result that fatal highway accidents decreased. This would suggest that, far from causing "carnage", legal marijuana might actually save lives.
Nearly one-third of Americans live in states which have now had a 15-20 year real-world experience with marijuana decriminalization, and the experience has been overwhelmingly favorable. Contrary to the fears expressed by some, marijuana usage rates (both the percentage reporting having ever used marijuana, and the frequency of use by those who do smoke) are the same in states that have decriminalized and in states where marijuana smokers are still arrested. Nor has there been any change in attitudes toward marijuana use among young people (high school seniors) in those states. In short, the evidence indicates that we can stop arresting marijuana smokers without harmful consequences.
Every major study on the subject concludes that marijuana use is not a threat to society, and its possession for personal use should be decriminalized. Why is our government ignoring the evidence in favor of a policy that has clearly failed?