Strokes in Young People

Drug use as a risk factor.

(First published 12-09-12)

When a stroke happens to anyone under the age of 55, a major suspect is drugs, specifically the stimulants—methamphetamine and cocaine. In the journal Stroke, researcher Brett Kissela and his associates provided additional evidence to support that unpleasant truth.

“We know that even with vascular risk factors that are prevalent—smoking, high blood pressure—most people still don’t have a stroke until they’re older,” Kissela said in a Reuters article. “When a young person has a stroke, it is probably much more likely that the cause of their stroke is something other than traditional risk factors.”

The modest study involved residents of Cincinnati and Northern Kentucky who had suffered a stroke before turning 55. The researchers found that the rate of substance abuse among the stroke group was higher than in control populations. This doesn’t prove that drug or alcohol addiction lead directly to strokes, since drug users often have additional risk factors for stroke and heart disease, particularly if they are also cigarette smokers.

But the suspected link between strokes and young drug abusers is by no means a new one. In 2007, scientists at the University of Texas Southwestern Medical Center in Dallas published a massive survey of more than 3 million records of Texas hospital patients from 2000 through 2003 in the Archives of General Psychiatry. This gigantic database gave the researchers access to the records of virtually every stroke patient in the state of Texas. The researchers found that strokes associated with amphetamine use among young people 18 to 44 years of age represented a rapidly growing category. In fact, the Texas group found that “the rate of strokes among amphetamine abusers was increasing faster than the rate of strokes among abusers of any other drug.”

Curiously, amphetamine and cocaine are responsible for different kinds of strokes. An ischemic stroke, the classic blood clot, is caused by a blockage of blood vessels to the brain. Hemorrhagic strokes result from bleeding caused by the rupture of a weakened blood vessel. In general, hemorrhagic strokes are more severe and more likely to cause death. And what the researchers found was more bad news for speed freaks: “Amphetamine abuse was strongly associated with hemorrhagic stroke, but not with ischemic stroke.” Cocaine abuse was more robustly linked to ischemic strokes. So, it’s not surprising that when it comes to drug and fatal strokes, the clear winner was amphetamine. It’s not entirely clear what causes the difference, but the investigators pointed out that meth injections in lab animals can cause microhemorrhaging, heart attacks, fragmentation of capillary beds, and something called “poor vascular filling.” For cocaine, the culprits are vasoconstriction and disrupted regulation of blood pressure.

More than 14 percent of strokes in hospitals “were accounted for by abuse of drugs,” the researchers wrote. The data showed that for patients with hemorrhagic strokes, “only amphetamine abuse, coagulation defects, and hypertension were strong independent predictors of in-hospital death.”

So what can we conclude? Either the number of speed users in these communities is increasing, or the existing speed communities are using the drug more intensely. Since the rate of increase of speed use was relatively modest during the study years, the researchers concluded that “increased rate in our hospital population is because of the increased intensity of methamphetamine use.” Meaning higher dosages, stronger meth, and more needles.

Sadly, much of this has been known since it least 1990. In that year, research published in the Annals of Internal Medicine, based on a study of stroke victims at San Francisco General Hospital, concluded that “the possibility of serious and sometimes fatal cerebrovascular accidents in people taking potent stimulants and using the intravenous route of administration is not as widely known as it needs to be.”

About 800,000 people in the U.S. suffer a stroke each year, according to figures from the U.S. Centers for Disease Control and Prevention. Strokes are considered America’s leading cause of serious long-term disability.

de los Rios F., Kleindorfer D.O., Khoury J., Broderick J.P., Moomaw C.J., Adeoye O., Flaherty M.L., Khatri P., Woo D. & Alwell K.;  (2012). Trends in Substance Abuse Preceding Stroke Among Young Adults: A Population-Based Study, Stroke, 43 (12) 3179-3183. DOI: 10.1161/STROKEAHA.112.667808

The Genetics of Smoking

Evidence from a 40-year study. 
 
(First published March 28, 2013)

Pediatricians have often remarked upon it: Give one adolescent his first cigarette, and he will cough and choke and swear never to try another one. Give a cigarette to a different young person, and she is off to the races, becoming a heavily dependent smoker, often for the rest of her life. We have strong evidence that this difference in reaction to nicotine is, at least in part, a genetic phenomenon.

But so what? Is there any practical use to which such knowledge can be put? As it turns out, the answer may be yes. People with the appropriate gene variations on chromosomes 15 and 19 move very quickly from the first cigarette to heavy use of 20 or more cigarettes per day, and have more difficulty quitting, according to a report  published in JAMA Psychiatry. From a public health point of view, these findings add a strong genetic rationale to early smoking prevention efforts— especially programs that attempt to “disrupt the developmental progression of smoking behavior” by means of higher prices and aggressive enforcement of age restrictions on smoking.

What the researchers found were small but identifiable differences that separated people with these genetic variations from other smokers. The gene clusters in question “provide information about smoking risks that cannot be ascertained from a family history, including information about risk for cessation failure,” according to authors Daniel W. Belsky, Avshalom Caspi, and colleagues at the University of North Carolina and Duke University.

The group looked at three prominent genome-wide association studies of adult smoking to see if the results could be applied to “the developmental progression of smoking behavior.” They used the data from the genome work to analyze the results of a 38-year prospective study of 1,037 New Zealanders, known as the Dunedin Study. A total of 405 cohort members in this study ended up as daily smokers, and only 20% of the daily smokers ever achieved cessation, defined as a year or more of continual abstinence.

The researchers came up with a multilocus genetic risk score (GRS) based on single-nucleotide polymorphisms associated with smoking behaviors. Previous meta-analyses had identified several suspects, specifically a region of chromosome 15 containing the CHRNA5-CHRNA3-CHRNB4 gene cluster, and a region of chromosome 19 containing the gene CYP2A6. These two clusters were already strong candidate genes for the development of smoking behaviors. For purpose of the study, the GRS was calculated by adding up the alleles associated with higher smoking quantity. The genetic risk score did not pertain to smoking initiation, but rather to the number of cigarette smoked per day.

When the researchers applied these genetic findings to the Dunedin population cohort, representing ages 11 to 38, they found that an unfortunate combination of gene types seemed to be pushing some smokers toward heavy smoking at an early age. Individuals with a high GRS score “progressed more rapidly to heavy smoking and nicotine dependence, were more likely to become persistent heavy smokers and persistently nicotine dependent, and had more difficulty quitting,” according to the study. However, these effects took hold only when young smokers “progressed rapidly from smoking initiation to heavy smoking during adolescence.” The variations found on chromosomes 15 and 19 influence adult smoking “through a pathway mediated by adolescent progression from smoking initiation to heavy smoking.”

Curiously, the group of people who had the lowest Genetic Risk Scores were not people who had never smoked, but rather people who smoked casually and occasionally—the legendary “chippers,” who can take or leave cigarettes, sometimes have one late at night, or a couple at parties, without ever falling victim to nicotine addiction. These “light but persistent smokers” were accounted for “with the theory that the genetic risks captured in our score influence response to nicotine, not the propensity to initiate smoking.”

Naturally, the study has limitations. Everyone in the Dunedin Study was of European descent, and the life histories ended at age 38. Nor did the study take smoking bans or different ages into account. The study cries out for replication, and hopefully that won’t be long in coming.

Could information of this sort be used to identify high-risk young people for targeted prevention programs? That is the implied promise of such research, but no, probably not. The gene associations are not so dramatic as to cause youngsters with the “bad” alleles to inevitably become chain smokers, nor do the right set of genes confer protection against smoking. It’s not that simple. However, the study is definitely one more reason to push aggressive smoking prevention efforts aimed at adolescents.

Belsky D.W.  Polygenic Risk and the Developmental Progression to Heavy, Persistent Smoking and Nicotine DependenceEvidence From a 4-Decade Longitudinal StudyDevelopmental Progression of Smoking Behavior, JAMA Psychiatry,   1. DOI: 10.1001/jamapsychiatry.2013.736

Graphics Credit: http://neurologicalcorrelates.com/

Why Will Power Fails

How to strengthen your self-control.

(First published August 12, 2013)

Reason in man obscured, or not obeyed,
Immediately inordinate desires,
And upstart passions, catch the government
From reason; and to servitude reduce
Man, till then free.
—John Milton, Paradise Lost

What is will power? Is it the same as delayed gratification? Why is will power “far from bulletproof,” as researchers put it in a recent article for Neuron? Why is willpower “less successful during ‘hot’ emotional states”? And why do people “ration their access to ‘vices’ like cigarettes and junk foods by purchasing them in smaller quantities,” despite the fact that it’s cheaper to buy in bulk?

 Everyone, from children to grandparents, can be lured by the pull of immediate gratification, at the expense of large—but delayed—rewards. By means of a process known as temporal discounting, the subjective value of a reward declines as the delay to its receipt increases. Rational Man, Economic Man, shouldn’t behave in a manner clearly contrary to his or her own best interest. However, as Crockett et. al. point out in a recent paper in Neuron “struggles with self-control pervade daily life and characterize an array of dysfunctional behaviors, including addiction, overeating, overspending, and procrastination.”

Previous research has focused primarily on “the effortful inhibition of impulses” known as will power. Crockett and coworkers wanted to investigate another means by which people resist temptations. This alternative self-control strategy is called precommitment, “in which people anticipate self-control failures and prospectively restrict their access to temptations.” Good examples of this approach include avoiding the purchase of unhealthy foods so that they don’t constitute a short-term temptation at home, and putting money in financial accounts featuring steep penalties for early withdrawal. These strategies are commonplace, and that’s because people generally understand that will power is far from foolproof against short-term temptation. People adopt strategies, like precommitment, precisely because they are anticipating the possibility of a failure of self-control. We talk a good game about will power and self-control in addiction treatment, but the truth is, nobody really trusts it—and for good reason.  The person who still trusts will power has not been sufficiently tempted.

The researchers were looking for the neural mechanisms that underlie precommitment, so that they could compare them with brain scans of people exercising simple self-control in the face of short-term temptation.

After behavioral and fMRI testing, the investigators used preselected erotic imagery rated by subjects as either less desirable ( smaller-sooner reward, or SS), or more highly desirable ( larger-later reward, or LL). The protocol is complicated, and the analysis of brain scans is inherently controversial. But previous studies have shown heightened activity in three brain areas when subjects are engaged in “effortful inhibition of impulses.” These are the dorsolateral prefrontal cortex (DLPFC), the inferior frontal gyrus (IFG), and the posterior parietal cortex (PPC). But when presented with opportunities to precommit by making a binding choice that eliminated short-term temptation, activity increased in a brain region known as the lateral frontopolar cortex (LFPC).  Study participants who scored high on impulsivity tests were inclined to precommit to the binding choice.

In that sense, impulsivity can be defined as the abrupt breakdown of will power. Activity in the LFPC has been associated with value-based decision-making and counterfactual thinking. LFPC activity barely rose above zero when subjects actively resisted a short-term temptation using will power.  Subjects who chose the option to precommit, who were sensitive to the opportunity to make binding choices about the picture they most wanted to see, showed significant activity in the LFPC. “Participants were less likely to receive large delayed reward when they had to actively resist smaller-sooner reward, compared to when they could precommit to choosing the larger reward before being exposed to temptation.”

Here is how it looks to Molly Crockett and her fellow authors of the Neuron article:

Precommitment is adaptive when willpower failures are expected…. One computationally plausible neural mechanism is a hierarchical model of self-control in which an anatomically distinct network monitors the integrity of will-power processes and implements precommitment decisions by controlling activity in those same regions. The lateral frontopolar cortex (LFPC) is a strong candidate for serving this role.

None of the three brain regions implicated in the act of will power were active when opportunities to precommit were presented.  Precommitment, the authors conclude, “may involve recognizing, based on past experience, that future self-control failures are likely if temptations are present. Previous studies of the LFPC suggest that this region specifically plays a role in comparing alternative courses of action with potentially different expected values.” Precommitment, then, may arise as an alternative strategy; a byproduct of learning and memory related to experiences “about one’s own self-control abilities.”

There are plenty of caveats for this study: A small number of participants, the use of pictorial temptations, and the short time span for precommitment decisions, compared to real-world scenarios where delays to greater rewards can take weeks or months. But clearly something in us often knows that, in the immortal words of Carrie Fisher, “instant gratification takes too long.” For this unlucky subset, precommitment may be a vitally important cognitive strategy. “Humans may be woefully vulnerable to self-control failures,” the authors conclude, “but thankfully, we are sometimes sufficiently far-sighted to circumvent our inevitable shortcomings.” We learn—some of us—not to put ourselves in the path of temptation so readily.


Photo Credit: http://cassandralathamjones.wordpress.com/

In Praise of Neurogenesis

A little sweat pays big dividends in recovery.

Scientists have long known that activities like learning, socialization and physical activity—key components of “environmental enrichment”—lead to the growth and development of nerve tissue that will become new brain cells, a process called neurogenesis. Such enrichment can include all manner of stimuli, but a group of researchers at the National Institute on Aging and the National Institute on Drug Abuse (NIDA) wanted to find out exactly how much of that neurogenic stimulus is due solely to exercise. Writing in the journal Learning and Memory, Tali Kobilo and coworkers went back to that most basic of lab experiments, mice running on an exercise wheel. Using a variety of conditions to permutate the mix of enrichment, running, running with other enrichment, and controls, the investigators concluded: “Here we show that running is the critical factor in stimulating adult hippocampal neurogenesis and enhancing mature BDNF [brain-derived neurotrophic factor] peptide levels. Moreover, enrichment in the absence of running does not increase adult hippocampal neurogenesis or BDNF levels in the hippocampus.” In addition: “New cell proliferation, survival, neuron number, and neurotrophin levels were enhanced only when running was accessible” to the test animals. “We conclude that exercise is the critical factor mediating increased BDNF levels and adult hippocampal neurogenesis.”

As a treatment modality for drug and alcohol addiction, physical exercise is often effective, quite well studied—and free. It is the most boring, the most mundane, the most predictable exhortation of them all—or perhaps the second most predictable, after the admonition to Eat Less.

Perhaps, suggests Jennifer Matesa in her book, The Recovering Body , it would be well to remember that doctors are not “paid to prescribe exercise.” She quotes Harvard’s biology professor Daniel E. Lieberman: “It is often said that exercise is medicine, but a more correct statement is that insufficient regular exercise is abnormal and pathological.” Matesa musters a chorus of trainers and exercise-oriented recovery experts to bolster her argument that simple exercise remains the single most overlooked element in most people’s recovery programs.

Matesa, whom I first encountered as the author of the excellent blog Guinevere Gets Sober, and later worked with at the online addiction and recovery magazine, The Fix, offers advice to “clean up the wreckage and recover the body’s health” during sobriety, and divides her book into five practices: exercise, nutrition, sleep, sexuality, and mindfulness meditation.

Body recovery is complex, Matesa writes. “You’re raising the levels of endorphins and dopamine in the body. You’re reregulating the body’s metabolism—its capacity to burn energy efficiently. You’re not just exercising biceps and triceps and deltoids or even chest, back, legs, and core. You’re also exercising the internal organs: heart, lungs, circulatory system, central nervous system (including the brain), and digestive system. You’re even exercising the skin by making it sweat.”

While one of the best things about exercise is that you can start at any point, with or without prior experience, there is a sense in which former jocks may have an edge here. Matesa interviews a former sports freak and recovering heroin addict who found her way back to the “cognitive- and muscle-memory” that gave her a head start in understanding what a fitness program is composed of. One thing that prevents people from working out, the former jock says, “is that they don’t know what to do and they feel overwhelmed. And we addicts get overwhelmed easily.”

A medical director of a Palm Beach detox center suggested that “twelve minutes of exercise per day with a heart rate of greater than one hundred twenty beats per minute” is enough to restore healthy sleeping patterns, for example. “The people who do that, their sleep architecture returns to normal in half the time that it takes people who don’t exercise. Twelve minutes.”

Matesa’s credentials as a recovering addict are impressive: alcohol abuse and opiate addiction, compulsive overeating, and shoplifting. As with many addictive shoplifters, she didn’t even need the things she stole. “The security woman pulled me into a messy, windowless back room, shut the door, looked me up and down, noted my Coach bag and middle-class clothing, regarded the stolen property in her hand [cheap earbuds], and said slowly, ‘you need to seek help.’” The book is published by Hazelden, and Matesa hews to the basic structure of 12 Step recovery programs. She also backs the controversial thinking of Dr. Gabor Mate, who believes that all addictions are the result of adverse childhood experiences, not genetics or any other physiological predilection.

Despite the years she logged with opiates, “my first chemical of abuse was sugar, my first addictive behavior was eating…. I eat sugar because it does all kinds of things drugs do…. when I was a kid, my diet was at least 80 percent refined and processed food, and almost all of that, essentially, was sugar. At age ten, I looked forward to my after-school snack the way my Dad looked forward to his first beer when he got home.”

She notes that a number of published studies have shown that “addicts in the first six months of recovery use sweet foods and refined, processed foods—junk food—to satisfy cravings for drugs and alcohol.” In addition, “sensible eating habits are seldom part of recovery strategies in detox and rehab facilities—this was a concern echoed by a number of treatment experts I talked with.”

“Recovery does not promise beauty or riches, everlasting affection and security or even sustained peace of mind,” Matesa concludes. “It promises that we’ll be able to negotiate one day—this one—in our right minds, awake. We get good at what we practice.”

Graphics Credit: http://www.thesportinmind.com/articles/exercise-addiction/

Alcohol and Your Heart

Health benefits of moderate drinking come under fire.

One of those things that “everybody knows” about alcohol is that a drink or two per day is good for your heart. But maybe not as good for your heart as no drinks at all.

Joint first authors Michael V. Holmes of the Department of Epidemiology and Public Health at University College in London, and Caroline E. Dale at the London School of Hygiene & Tropical Medicine in London, recently published a multi-site meta-analysis of epidemiological studies centering on a common gene for alcohol metabolization. The report, published in the UK journal BMJ, brings “the hypothesized cardioprotective effect of alcohol into question,” according to the authors.

People who are born with a particular variant in the gene controlling for the expression of alcohol dehydrogenase, the major enzyme involved in converting alcohol into waste products, will show the familiar flush reaction when they drink. Alcohol, literally, can make many of them sick. This genetic variant, in combination with other enzymes, can be strongly protective against alcohol, and is much more commonly found among Asian populations. Roughly 40% of Japanese, Korean, and Northeastern Chinese populations show the characteristic “Asian glow” to one degree or another if they choose to drink.  (One reason why this effect isn't better known is that the condition is close to nonexistent in Westerners).

 People with this alcohol dehydrogenase deficiency, the researchers found, not only consume less alcohol, for obvious reasons, but “had lower, not higher, odds of developing coronary heart disease regardless of whether they were light, moderate, or heavy drinkers.”  Here are the conclusions in detail: “Carriers of the rs1229984 A-allele had lower levels of alcohol consumption and exhibited lower levels of blood pressure, inflammatory biomarkers, adiposity measures, and non-HDL cholesterol, and reduced odds of developing coronary heart disease, compared with non-carriers of this allele.”

The authors conclude that "reduction of alcohol consumption, even for light to moderate drinkers, is beneficial for cardiovascular health.”

How does this work? The researchers aren’t completely sure, but note that the “most widely proposed mechanism” is an increase in high-density lipoprotein (HDL) cholesterol. “Although an HDL cholesterol raising effect of alcohol has been reported in experimental studies, the small sample size and short follow-up means existing studies may be prone to bias,” thereby limiting their usefulness. Moreover, the BMJ study itself found “no overall difference between allele carriers and non-carriers in HDL concentration.”

Like most meta-studies, this one has its strengths and weaknesses. The study used a large sample size, used detailed alcohol phenotypic data, and didn't have to deal with the inherent biases of observational-type studies. On the minus side, the lack of a connection between the allele in question and HDL levels is troubling, and stroke data was lacking.

But overall, the authors believe that "social pressure in heavier drinking cultures is unlikely to override the effect of the genetic variant on alcohol consumption."

In retrospect, there have been some trouble spots along the way: A 2008 study in Current Atherosclerosis Reports concluded:

In the absence of large randomized trials of moderate alcohol consumption and heart failure, we cannot exclude residual confounding or unmeasured confounding as possible explanations for the observed relationships. Thus, for patients who do not consume any alcohol, it would be premature to recommend light-to-moderate drinking as a means to lower the risk of heart failure, given the possible risk of abuse and resulting consequences.

At present, the American Heart Association does not recommend drinking any amount of wine or other alcoholic beverages in order to gain potential health benefits.


Holmes M.V.,  L. Zuccolo,  R. J. Silverwood,  Y. Guo,  Z. Ye,  D. Prieto-Merino,  A. Dehghan,  S. Trompet,  A. Wong &  A. Cavadino &  (2014). Association between alcohol and cardiovascular disease: Mendelian randomisation analysis based on individual participant data, BMJ, 349 (jul10 6) g4164-g4164. DOI: http://dx.doi.org/10.1136/bmj.g4164

Photo credit: http://qsystem.gblifesciences.com/

The Chemistry of Modern Marijuana

Is low-grade pot better for you than sinsemilla?

First published September 3, 2013.

Australia has one of the highest rates of marijuana use in the world, but until recently, nobody could say for certain what, exactly, Australians were smoking. Researchers at the University of Sydney and the University of New South Wales  analyzed hundreds of cannabis samples seized by Australian police, and put together comprehensive data on street-level marijuana potency across the country. They sampled police seizures and plants from crop eradication operations. The mean THC content of the samples was 14.88%, while absolute levels varied from less than 1% THC to almost 40%.  Writing in PLoS ONE, Wendy Swift and colleagues found that roughly ¾ of the samples contained at least 10% total THC. Half the samples contained levels of 15% or higher—“the level recommended by the Garretsen Commission as warranting classification of cannabis as a ‘hard’ drug in the Netherlands.”

In the U.S., recent studies have shown that THC levels in cannabis from 1993 averaged 3.4%, and then soared to THC levels in 2008 of almost 9%. THC loads more than doubled in 15 years, but that is still a far cry from news reports erroneously referring to organic THC increases of 10 times or more.

CBD, or cannabidiol, another constituent of cannabis, has garnered considerable attention in the research community as well as the medical marijuana constituency due to its anti-emetic properties. Like many other cannabinoids, CBD is non-psychoactive, and acts as a muscle relaxant as well. CBD levels in the U.S. have remained consistently low over the past 20 years, at 0.3-0.4%. In the Australian study, about 90% of cannabis samples contained less than 0.1% total CBD, based on chromatographic analysis, although some of the samples had levels as high as 6%.

The Australian samples also showed relatively high amounts of CBG, another common cannabinoid. CBG, known as cannabigerol, has been investigated for its pharmacological properties by biotech labs. It is non-psychoactive but useful for inducing sleep and lowering intra-ocular pressure in cases of glaucoma.

CBC, yet another cannabinoid, also acts as a sedative, and is reported to relieve pain, while also moderating the effects of THC. The Australian investigators believe that, as with CBD, “the trend for maximizing THC production may have led to marginalization of CBC as historically, CBC has sometimes been reported to be the second or third most abundant cannabinoid.”

Is today’s potent, very high-THC marijuana a different drug entirely, compared to the marijuana consumed up until the 21st Century? And does super-grass have an adverse effect on the mental health of users? The most obvious answer is, probably not. Recent attempts to link strong pot to the emergence of psychosis have not been definitive, or even terribly convincing. (However, the evidence for adverse cognitive effects in smokers who start young is more convincing).

It’s not terribly difficult to track how ordinary marijuana evolved into sinsemilla. Think Luther Burbank and global chemistry geeks. It is the historical result of several trends: 1) Selective breeding of cannabis strains with high THC/low CBD profiles, 2) near-universal preference for female plants (sinsemilla), 3) the rise of controlled-environment indoor cultivation, and 4) global availability of high-end hybrid seeds for commercial growing operations. And in the Australian sample, much of the marijuana came from areas like Byron Bay, Lismore, and Tweed Heads, where the concentration of specialist cultivators is similar to that of Humboldt County, California.

The investigators admit that “there is little research systematically addressing the public health impacts of use of different strengths and types of cannabis,” such as increases in cannabis addiction and mental health problems. The strongest evidence consistent with lab research is that “CBD may prevent or inhibit the psychotogenic and memory-impairing effects of THC. While the evidence for the ameliorating effects of CBD is not universal, it is thought that consumption of high THC/low CBD cannabis may predispose users towards adverse psychiatric effects….”

The THC rates in Australia are in line with or slightly higher than average values in several other countries. Can an increase in THC potency and corresponding reduction in other key cannabinoids be the reason for a concomitant increase in users seeking treatment for marijuana dependency? Not necessarily, say the investigators. Drug courts, coupled with greater treatment opportunities, might account for the rise. And schizophrenia? “Modelling research does not indicate increases in levels of schizophrenia commensurate with increases in cannabis use.”

One significant problem with surveys of this nature is the matter of determining marijuana’s effective potency—the amount of THC actually ingested by smokers. This may vary considerably, depending upon such factors as “natural variations in the cannabinoid content of plants, the part of the plant consumed, route of administration, and user titration of dose to compensate for differing levels of THC in different smoked material.”

Wendy Swift and her coworkers call for more research on cannabis users’ preferences, “which might shed light on whether cannabis containing a more balanced mix of THC and CBD would have value in the market, as well as potentially conferring reduced risks to mental wellbeing.”

Graphics Credit: http://www.ironlabsllc.co/view/learn.php

Swift W., Wong A., Li K.M., Arnold J.C. & McGregor I.S. (2013). Analysis of Cannabis Seizures in NSW, Australia: Cannabis Potency and Cannabinoid Profile., PloS one, PMID: 23894589

Synthetic Cannabis Can Cause Cyclic Vomiting

Another reason to skip "Spice."

Cannabinoid hyperemesis,  as it is known, was not documented in the medical literature until 2004. Case studies of more than 100 patients have been reported since then. The biomedical researcher who blogs as Drugmonkey has documented cases of hyperemesis that had been reported in Australia and New Zealand, as well as Omaha and Boston in the U.S.

As Drugmonkey reported, patients who are heavy marijuana smokers, and who experience cyclic nausea and vomiting, “discovered on their own that taking a hot bath or shower alleviated their symptoms. So afflicted individuals were taking multiple hot showers or baths per day to obtain symptom relief.”

A recent report in Mayo Clinic Proceedings by Dr. Benjamin L. Bick and colleagues documents the 3rd reported case of the syndrome in a regular user of synthetic Spice-style products, rather than marijuana. It’s now clear that THC isn’t necessary for triggering the rare but highly unpleasant vomiting cycle in a small fraction of users.

“A 29-year-old man presented with a 2-year history of recurrent episodes of severe nausea and vomiting with epigastric pain,” according to the authors. Drug tests were negative, including tests for THC. “For his more recent symptoms, he was evaluated multiple times in the primary care setting and emergency department. At each visit he denied use of any ‘illicit substances or drugs’ since he quit using marijuana.”

“Hot showers for up to an hour provided relief. He reported experiencing similar symptoms more than 5 years previously when he was regularly smoking marijuana, and these symptoms resolved with the cessation of cannabis.”

The patient eventually admitted to regularly smoking products sold as K2 and Kryptonite, containing “unidentified and uncertain synthetic cannabinoid agonists marketed as ‘legal’ herbal incense.”

The Mayo clinicians offer diagnostic criteria for cannabis hyperemesis, which include “long-term cannabis use, cyclic nausea and vomiting, resolution with cessation of cannabis, relief of symptoms with hot showers, abdominal pain, and weekly use of marijuana.” And theirs is the third published report of cannabis hyperemesis in a male patient after synthetic cannabinoid use. “After 6 months abstinence,” they report, “he noted complete resolution of symptoms.”

The researchers conclude that “synthetic cannabinoids can be potent agonists of the cannabinoid CB1 receptors, which are the same receptors by which THC produces its effects.” While only three Spice-related incidents of hyperemesis syndrome have thus far been identified, it may go unrecognized in patients using synthetic cannabinoids:

 A urine drug screen negative for THC may point physicians away from this syndrome, and patients may not report use if they believe they are using herbal products rather than illicit drugs. Therefore, regardless of negative urine drug screen results and patient denial of cannabis use, physicians should have a high index of suspicion for synthetic CH syndrome in patients who present with classic symptoms of cyclic emesis.

Sarah A. Buckley and Nicholas M. Mark at the NYU School of Medicine, after reviewing 16 published papers on the syndrome,  asked the obvious question: "How can marijuana, which is used in cancer clinics as an anti-emetic, cause intractable vomiting? And why would symptoms abate in response to high temperature?"

We don't know the answer, but Buckley and Mark note that "cannabis disrupts autonomic and thermoregulatory functions of the hippocampal-hypothalamic-pituitary system," which is loaded with CB-1 receptors. The researchers conclude, however, that the link between marijuana and thermoregulation "does not provide a causal relationship" for what they refer to as "this bizarre learned behavior.”

Bick B.L. &  Thomas F. Mangan (2014). Synthetic Cannabinoid Leading to Cannabinoid Hyperemesis Syndrome, Mayo Clinic Proceedings, 89 (8) 1168-1169. DOI: http://dx.doi.org/10.1016/j.mayocp.2014.06.013

Photo credit: http://www.aquaticcreationsnc.com/custom.htm