Mom sent me a link to a recent article that appeared in The New York Times on cannabis: This Is Your Brain on Drugs by Abigail Sullivan Moore.
The gray matter of the nucleus accumbens, the walnut-shaped pleasure center of the brain, was glowing like a flame, showing a notable increase in density. “It could mean that there’s some sort of drug learning taking place,” speculated Jodi Gilman, at her computer screen at the Massachusetts General Hospital-Harvard Center for Addiction Medicine. Was the brain adapting to marijuana exposure, rewiring the reward system to demand the drug?
Dr. Gilman was reviewing a composite scan of the brains of 20 pot smokers, ages 18 to 25. What she and fellow researchers at Harvard and Northwestern University found within those scans surprised them. Even in the seven participants who smoked only once or twice a week, there was evidence of structural differences in two significant regions of the brain. The more the subjects smoked, the greater the differences.
Moderate marijuana use by healthy adults seems to pose little risk, and there are potential medical benefits, including easing nausea and pain.
The key here is moderation, which is difficult with rewarding activities. People will struggle with this, and some will never be able to effectively moderate their consumption, despite their best attempts.
But it has long been known that, with the brain developing into the mid-20s, young people who smoke early and often are more likely to have learning and mental health problems. Now researchers suggest existing studies are no longer sufficient. Much of what’s known is based on studies conducted years ago with much less powerful pot.
No surprise here. That our scientific studies have been conducted with much less powerful cannabis is a result of the hurdles that academics must pass in order to receive cannabis for study. The US National Institute on Drug Abuse (NIDA) recently opened up bidding on a contract for the 12-acre cannabis farm: I don’t follow this closely, but the University of Mississippi (‘Ole Miss) has had a monopoly on cannabis production for research since 1968.
Marijuana samples seized by the federal Drug Enforcement Agency show the concentration of THC, the drug’s psychoactive compound, rising from a mean of 3.75 percent in 1995 to 13 percent in 2013. Potency seesaws depending on the strain and form. Fresh Baked, which sells recreational marijuana in Boulder, Colo., offers “Green Crack,” with a THC content of about 21 percent, and “Phnom Penh,” with about 8 percent. The level in a concentrate called “Bubble Hash” is about 70 percent; cartridges for vaporizers, much like e-cigarettes, range from 15 to 30 percent THC.
Cultivation techniques have been boiled down to an exact science. The trend towards increased potency should continue, given reduced barriers to information exchange and the growing number of institutions that offer courses on hydroponics.
High-THC marijuana is associated with paranoia and psychosis, according to a June article in The New England Journal of Medicine. “We have seen very, very significant increases in emergency room admissions associated with marijuana use that can’t be accounted for solely on basis of changes in prevalence rates,” said Nora D. Volkow, director of the National Institute on Drug Abuse and a co-author of the THC study. “It can only be explained by the fact that current marijuana has higher potency associated with much greater risk for adverse effects.” Emergency room visits related to marijuana have nearly doubled, from 66,000 in 2004 to 129,000 in 2011, according to the Substance Abuse and Mental Health Services Administration.
As alarming as this sounds, I would speculate that the majority of ER visits stem from the user biting off more than they can chew. I believe that the number of cases of paranoia would drop if cannabis consumption were no longer taboo. To disprove my hypothesis, one could study data on ER admissions from those states that have moved to legalize cannabis for recreational use, weighted for the surveyed population at the time of data collection.
Higher potency may also accelerate addiction. “You don’t have to work so hard to get high,” said Alan J. Budney, a researcher and professor at Dartmouth’s medical school. “As you make it easier to get high, it makes a person more vulnerable to addiction.” Among adults, the rate is one of 11; for teenagers, one of six.
Professor Budney is requested to present his data; else I see no reason to believe his claim on account of his credentials.
Concerns over increasing potency, and rising usage among the young, is giving new urgency to research.
For the Harvard-Northwestern study, published in the April issue of The Journal of Neuroscience, the team scanned the brains of 40 young adults, most from Boston-area colleges. Half were nonusers; half reported smoking for one to six years and showed no signs of dependence. Besides the seven light smokers, nine used three to five days a week and four used, on average, daily. All smokers showed abnormalities in the shape, density and volume of the nucleus accumbens, which “is at the core of motivation, the core of pleasure and pain, and every decision that you make,” explained Dr. Hans Breiter, a co-author of the study and professor of psychiatry and behavioral sciences at Northwestern’s medical school.
Nothing new here. The debate about cannabis use’s link with amotivational syndrome goes on.
Similar changes affected the amygdala, which is fundamental in processing emotions, memories and fear responses.
What is already known is that in casual users, THC can disrupt focus, working memory, decision making and motivation for about 24 hours. “The fact that we can see these structural effects in the brain could indicate that the effects of THC are longer lasting than we previously thought,” said Dr. Gilman, an instructor in psychology at Harvard’s medical school.
The study was preliminary and small, and attempts to replicate it are underway. Meanwhile, Dr. Gilman is trying to figure out how the findings relate to brain function and behavior.
One day in September, she was assessing Emma, a student who said her smoking — almost every day — didn’t interfere with school, work or other obligations. For $100 to go toward study-abroad plans, Emma politely plowed through nearly three hours of tests on cognitive functions that are or might be affected by THC, like the ability to delay gratification (would it be better to have $30 tonight or $45 in 15 days?) and motivation (a choice between computer games, the harder one offering a bigger payoff). For memory, Emma listened to lists of words, repeating back those she recalled. Next came risk. Would she bungee jump? Eat high-cholesterol food? (“These kids tend to be risk takers, particularly with their own health and safety,” Dr. Gilman said.)
A final test: Did Emma crave a joint? Her response: somewhat.
Dr. Gilman is concerned about pot’s impact on the college population. “This is when they are making some major life decisions,” she said, “choosing a major, making long-lasting friendships.”
This much is true. One could make the case that college students know too little about the world and of themselves to be making such major life decisions, but I digress.
Dr. Volkow noted another problem: Partying on a Saturday night may hinder studying for a test or writing a paper due on Monday. “Maybe you won’t have the motivation to study, because there’s no reward, no incentive,” she said.
There’s a larger, more systemic problem behind this, and it comes down to our collective self-control. We’ve been conditioned to want things now.
Evidence of long-term effects is also building. A study released in 2012 showed that teenagers who were found to be dependent on pot before age 18 and who continued using it into adulthood lost an average of eight I.Q. points by age 38. And last year at Northwestern, Dr. Breiter and colleagues also saw changes in the nucleus accumbens among adults in their early 20s who had smoked daily for three years but had stopped for at least two years.
They had impaired working memories as well. “Working memory is key for learning,” Dr. Breiter said. “If I were to design a substance that is bad for college students, it would be marijuana.”
The first sentence of the first paragraph is alarming, but one has to bear in mind that scientific studies are sometimes flawed. Here is a Washington Post article addressing that particular 2012 study. The original study is entitled, Persistent cannabis users show neuropsychological decline from childhood to midlife, and the full paper can be found here.
More work should be done to better understand cannabis use, and these studies are a step in the right direction. While the tone of the article is decidedly alarmist, one would do well to read further into the studies mentioned here, and to follow current developments if time allows. My personal views on cannabis evolve the more that I read on the subject. Anyone who has an interest in cannabis should examine NORML’s Principles of Responsible Cannabis Use.
Consider especially the fourth point: Resist Abuse
Use of cannabis, to the extent that it impairs health, personal development or achievement, is abuse, to be resisted by responsible cannabis users.
Abuse means harm. Some cannabis use is harmful; most is not. That which is harmful should be discouraged; that which is not need not be.
Wars have been waged in the name of eradicating “drug abuse”, but instead of focusing on abuse, enforcement measures have been diluted by targeting all drug use, whether abusive or not. If cannabis abuse is to be targeted, it is essential that clear standards be developed to identify it.