Though it is certainly not the only factor, research repeatedly finds that price affects consumption of psychoactive and other drugs, even among the heaviest users. A 2007 study in Health Policy found that a 10% increase on cigarette taxes would cut tobacco consumption by 3% to 5%. Other data suggest that raising taxes reliably increases quit-smoking attempts, successful quitting and reduction in use by those who don't quit — and that's in users of nicotine, which is more than twice as addictive as marijuana.
"We know from the alcohol and tobacco literature that higher prices are a big disincentive for people using drugs," says Dr. Evan Wood, founder of the International Centre for Science in Drug Policy, who was the lead author on a recent report on marijuana regulation. (More on TIME.com:Will Legalization Increase Marijuana Use?)
"I don't think there's any doubt that heavy cannabis use is going to turn out to be price sensitive. I'm in favor of that," says Mark Kleiman, director of the drug policy analysis program at UCLA. "My view goes back to my favorite Johnny Walker Black ad that ran in the New Yorker. [It said]: if the difference in price between Johnny Walker Black and ordinary scotch matters to you, you're drinking too much."
Likewise, says Kleiman, "Anybody who would be bothered by a $2-per-joint tax is smoking too much."
Next:Set a Legal Smoking AgeMore on Time.com:See photos of cannabis cultureIs Marijuana Addictive? It Depends How You Define Addiction
However residents of California vote next week on Prop 19, the state’s marijuana-legalization initiative, polling among young people shows that they overwhelmingly favor a change in marijuana law — so it’s likely that the current state of pot prohibition won’t last forever. That leads Healthland to ask: what would be the best way to legally control marijuana? Here are our proposed regulations, with comments from drug-policy experts.