Compared to some of the drugs out there, cannabis can seem relatively harmless. It doesn’t have the ruinous effects of methamphetamines or even substances like synthetic pot. But there has long been suspicion that heavy use might have long-term effects on IQ, for instance [pdf].
Factors that tend to accompany cannabis consumption, such as the use of other drugs and alcohol and, in adolescents, a tendency to skip class, have made it difficult to decisively pin a dip in IQ to marijuana use. To clear away the noise, the authors of a new study in the Proceedings of the National Academy of Sciences turned to the reams of data from the Dunedin Multidisciplinary Health and Development Study, and they’ve found that on average, by the time they reached age 38, heavy pot users diagnosed with cannabis dependence during adolescence suffered an 8-point drop in IQ.
The synthetic marijuana product Spice
Synthetic, or designer, drugs are chemical compounds that imitate the effects of marijuana, stimulants, and other recreational drugs. Unlike illegal substances, synthetics are easily accessible to users who want to get high without risking legal repercussions. Although the Federal Analog Act of 1986 prevents the sale of chemicals with structures that are “substantially similar” to those of illegal drugs, it only applies to drugs intended for human consumption. Manufacturers easily leap this hurdle by labeling their synthetic drugs as non-ingestible products such as incense, potpourri, or bath salts. Taking a different tack, the government recently passed the Synthetic Drug Abuse Prevention Act of 2012, which makes some of the popular designer drugs illegal. But did this really make synthetics less available?
Marijuana, long known as a recreational drug, has earned some respectability with its growing reputation as a pain reliever for those who suffer from cancer, multiple sclerosis, and other ailments. And now, cannabis’s seedy reputation may go entirely to pot: a new strain called Avidekel preserves the drug’s medical properties but does not get users high.
The effects of various breeds of marijuana depend on their balance of the chemicals called cannabinoids. One cannabinoid, called tetrahydrocannabinol or THC, acts on the brain’s cannabinoid receptors to create the sensation of being high. While this feeling is the goal for recreational users, it can be an unwanted side effect for patients who smoke medical marijuana to relieve their pain and then find themselves unable to work, run errands in a car, or function normally until the drug’s effects wear off. The primary reason these users turn to marijuana in the first place is a different cannabinoid, called cannabidiol, which reduces inflammation without any psychoactive side effects.
Human astrocyte. The vivid color is from GFP, not drugs.
The real news is the importance of a type of brain cells called astroglia, which have long been ignored while researchers focus on neurons. THC, the psychoactive chemical in marijuana, impairs working memory by connecting to astroglia, according to a new paper published in Cell. So the star-shaped astroglia turn out to be the real star of this study.
Drugs have a habit of making their way from our bodies into the environment: they’ve frequently been found in waste water, drinking water, and rivers (not to mention on dollar bills). But they could also be rising into the air, and a new study suggests their aerial concentrations could give scientists a clue to what, exactly, is happening on the ground below. Following up on earlier research showing that cocaine was present in the air above the cities of Taranto and Rome, Italian researchers at the Institute of Atmospheric Pollution Research in Rome took about 60 samples of air in various regions and tested for a number of contaminants, including cocaine, cannabinoids (chemicals found in marijuana), and more common pollutants, like ozone and hydrocarbons. When they looked to see whether there was a correlation between cocaine concentration and addicts’ requests for treatment in particular geographical areas, they found a very strong relationship. Weaker correlations existed between cocaine concentration and police seizures of cocaine and concentration and seizure of all kinds of illicit substances.
The team is excited about the possibility of using aerial cocaine concentration to get a sense of drug use levels, a notoriously slippery thing to measure, and possibly other activities that sometimes occur in tandem with drug use, like robberies. However, their approach didn’t turn up any significant correlations between crime-related activities and cannabinoids, which is interesting—what does that mean about the social correlates of marijuana use (or, alternatively, about the fraction of cannabinoids that actually make into the air)? If you’re worried about getting high from the air, it seems unlikely that concentrations are high enough to have an effect. But who knows—that’s a question that has yet to be addressed.
If you remember anything from statistics class, it’s probably that correlation ain’t no causation. Just because two numbers happen to go up at the same time doesn’t mean that one is causing the other to rise (or fall, or hold steady, or whatever). If there isn’t a plausible explanation for how the two might be connected, and proof that that explanation is indeed the cause, all you have is a couple of lines on a chart.
So it’s a move in the right direction when people try to suss out connections between two variables they have a hunch are related. But seeking such a connection can lead to some pretty convoluted reasoning. A new paper—unpublished, but released for discussion—claims that the passage of states’ medical marijuana laws cause decreased traffic fatalities, following on the researchers’ intuition that people might smoke pot instead of drinking alcohol if marijuana were more readily obtainable, and that driving while high is less dangerous than driving drunk. Their logic goes like this: if medical marijuana laws make pot more easily available, and people smoke more pot after laws are passed, and they buy less alcohol because of that, then there would be fewer traffic deaths.
What’s The News: Three 16-year-old teenage boys in Texas had heart attacks shortly after smoking a product called k2, or Spice, according to a study published this month in the journal Pediatrics. The report highlights a growing public health problem: the increased availability and use of synthetic cannabinoids, which when smoked mimic the effects of marijuana but typically can’t be detected in drug tests. While the U.S. Drug Enforcement Agency secured an emergency, one-year ban of five synthetic cannabinoids in March of this year, most of the hundreds of such chemicals remain basically legal, widely available, little understood, and potentially harmful.
When rats were injected with a chemical similar to marijuana’s main ingredient, THC, shortly after a undergoing a severely stressful event, they showed a significant reduction in symptoms like those seen in people with post-traumatic stress disorder. The study tested a synthetic cannabinoid called WIN 55,212-2, which was injected directly into the animals’ amygdala, a brain region involved in the regulation of emotions like fear and anxiety. Timing was important. Rats given the drug two and 24 hours after the stressor—being forced to swim for 15 minutes—appeared less “traumatized” when tested a week later, compared with those given the drug 48 hours later or given no drug at all. While the study adds to the already large and complex pile of evidence that the cannabinoid system has a vital role in regulating emotions like anxiety, it’s far from proving that cannabinoids will be useful for treating PTSD in humans.
New sea creatures, humongous stars, and cockroach antibiotics: Those are just a few reader favorites from this year in science. As 2010 comes to a close, we bring you a dozen of the most popular 80beats posts of the year.
For more great stories from the year in science, check out DISCOVER’s Top 100 Stories of the Year.
California’s Proposition 19, a November ballot initiative to legalize marijuana, has fueled the ongoing fight over the drug’s health risks. While that battle has a month to go, a new study out in the British Journal of Psychiatry this backs up the idea that pot’s cognitive impairment is all about the makeup of the marijuana you’re smoking.
Valerie Curran and colleagues studied 134 volunteers as those volunteers smoked from their private stashes in their homes. The scientists had their subjects take a series of cognitive tests, both high and sober. They then took a small portion of the pot to the lab for analysis.
Curran found striking differences in the chemical compositions of different users’ marijuana, and those differences appeared to play a large role in how well the smokers performed on the tests while high.