Teens who routinely smoke marijuana risk a long-term drop in their IQ, a new study suggests.

The researchers didn’t find the same IQ dip for people who became frequent users of pot after 18. Although experts said the new findings are not definitive, they do fit in with earlier signs that the drug is especially harmful to the developing brain.

Study participants from New Zealand were tested for IQ at age 13, likely before any significant marijuana use, and again at age 38. The mental decline between those two ages was seen only in those who started regularly smoking pot before age 18.

The governor will call for the decriminalization of possession of small amounts of marijuana in public view, administration officials said. Advocates of such a change say the offense has ensnared tens of thousands of young black and Latino men who are stopped by the New York City police for other reasons but after being instructed to empty their pockets, find themselves charged with a crime.

The police in New York City made 50,684 arrests last year for possession of a small amount of marijuana, more than for any other offense, according to an analysis of state data by Harry G. Levine, a sociologist at Queens College. 

Update: Mayor Bloomberg supports Cuomo’s plan.

A self-selected group of boys at Punahou School who loved basketball and good times called themselves the Choom Gang. Choom is a verb, meaning “to smoke marijuana.”

As a member of the Choom Gang, Barry Obama was known for starting a few pot-smoking trends. The first was called “TA,” short for “total absorption.” To place this in the physical and political context of another young man who would grow up to be president, TA was the antithesis of Bill Clinton’s claim that as a Rhodes scholar at Oxford he smoked dope but never inhaled.

Along with TA, Barry popularized the concept of “roof hits”: when they were chooming in the car all the windows had to be rolled up so no smoke blew out and went to waste; when the pot was gone, they tilted their heads back and sucked in the last bit of smoke from the ceiling.

When you were with Barry and his pals, if you exhaled precious pakalolo (Hawaiian slang for marijuana, meaning “numbing tobacco”) instead of absorbing it fully into your lungs, you were assessed a penalty and your turn was skipped the next time the joint came around. “Wasting good bud smoke was not tolerated,” explained one member of the Choom Gang, Tom Topolinski…

Barry also had a knack for interceptions. When a joint was making the rounds, he often elbowed his way in, out of turn, shouted “Intercepted!,” and took an extra hit. No one seemed to mind.

In another section of the [senior] yearbook, students were given a block of space to express thanks and define their high school experience. … Nestled below [Obama’s] photographs was one odd line of gratitude: “Thanks Tut, Gramps, Choom Gang, and Ray for all the good times.” … A hippie drug-dealer made his acknowledgments; his own mother did not.

300 economists, including three nobel laureates, have signed a petition calling attention to the findings of a paper by Harvard economist Jeffrey Miron, which suggests that if the government legalized marijuana it would save $7.7 billion annually by not having to enforce the current prohibition on the drug. The report added that legalization would save an additional $6 billion per year if the government taxed marijuana at rates similar to alcohol and tobacco.

That’s as much as $13.7 billion per year…

[Marijuana] dispensaries, and even landlords of dispensary-operators, all over California, Colorado and Montana have been getting menacing letters. Many have closed shop. Growers and users are by turns livid and scared. Some have protested. Others have ducked back into the black market, as in the old days before medical marijuana was allowed.

The question is why the federal government is doing this. On the one hand there is a federal law, the Controlled Substances Act, which recognises no exception for medical marijuana and thus considers all use and trade of it criminal. But on the other hand the Obama administration originally signalled that it would not deliberately clash with the states about weed. In the so-called Ogden memo of 2009, the Justice Department advised its lawyers to leave small-beer marijuana enforcement to the states and focus on graver crimes.

But then, last year, the administration issued the Cole memo (these things are named after the deputy attorneys-general who draft them). It seemed, in dense verbiage, to suggest that the Ogden memo had been misunderstood, and that federal prosecutors should indeed go after the cannabis trade, especially if they suspect that serious money is being made.

The overall effect has been to confuse everybody and leave matters entirely at the discretion of individual prosecutors. Thus there are few signs of federal aggression in New Mexico, Rhode Island or Vermont, for instance. Rather, the crackdown appears to be occurring in just six federal districts—the four in California, and those in Montana and Colorado.

To Ethan Nadelmann, the head of the Drug Policy Alliance, which lobbies for an end to the failed “war on drugs”, this suggests that six federal prosecutors may be acting on their own, perhaps even in conflict with the Obama administration. The president, in this scenario, is too afraid to touch anything that looks soft on drugs in an election year and stands weakly by.

States do not like it. Democratic and Republican legislators from five medical-marijuana states have written an open letter to Barack Obama to end the “chaos” and leave this matter to the states. Christine Gregoire and Lincoln Chafee, governors of Washington state and Rhode Island, have asked the federal government to reclassify marijuana from a Schedule I drug (like heroin, say) to a Schedule II drug (like morphine) so that doctors can at least prescribe it safely in certain circumstances. Vermont, Colorado, Hawaii, and Connecticut have joined in the request. Ms Gregoire has already found herself having to veto a medical-marijuana bill she supports for fear that her state employees may be indicted by federal prosecutors. To all the good reasons for drug reform can now be added this classically conservative one: states’ rights.