Friday, January 23, 2015

The Losing Battle For Perpetual Reward

Or why you can't stay high forever.

The amphetamine high, like the cocaine high, is a marvel of biochemical efficiency. Stimulants work primarily by blocking the reuptake of dopamine molecules in the synaptic gap between nerve cells. Dopamine remains stalled in the gap, stimulating the receptors, resulting in higher dopamine concentrations and greater sensitivity to dopamine in general. Since dopamine is involved in moods and activities such as pleasure, alertness and movement, the primary results of using cocaine or speed—euphoria, a sense of well being, physical alertness, and increased energy—are easily understood. Even a layperson can tell when lab rats have been on a meth binge. The rapid movements, sniffing, and sudden rearing at minor stimuli are not that much different in principle from the outward signs of meth intoxication among higher primates.

Chemically, cocaine and amphetamine are very different compounds. Psychoactively, however, they are very much alike. Of all the addictive drugs, smoked cocaine and speed have the most direct and most devastatingly euphoric effect on the dopamine systems of the brain. Cocaine and amphetamine produce rapid classical conditioning in addicts, demonstrated by the intense cravings touched off by such stimuli as the sight of a building where the user used to buy or sell. Environmental impacts of this nature can produce marked blood flow increases to key limbic structures in abstinent addicts.

In clinical settings, cocaine users have a hard time distinguishing between equal doses of cocaine and Dexedrine, administered intravenously. As we know, it is the shape of the molecule that counts. The amphetamines are shaped like dopamine and norepinephrine, two of the three reward chemicals. Speed, then, is well suited to the task of artificially stimulating the limbic reward pathway. Molecules of amphetamine displace dopamine and norepinephrine in the storage vesicles, squeezing those two neurotransmitters into the synaptic gap and keeping them there. By mechanisms less well identified, cocaine accomplishes the same feat. Both drugs also interfere with the return of dopamine, norepinephrine, and serotonin molecules to their storage sacs, a procedure known as reuptake blocking. Cocaine works its effects primarily by blocking the reuptake of dopamine.

Amphetamine was once one of the most widely prescribed drugs in the pharmacological cornucopia. It exists in large part now as a recreational drug of choice, abuse, and addiction. The same is true of cocaine. It was replaced as a dental anesthetic long ago, in favor of non-addictive variants like Novocain. The same tragic list of statistical side effects that apply to abusers of alcohol, heroin and nicotine also apply to stimulant abusers: Increased risk of car accidents, homicides, heart attack, and strokes.

In the late 1990s, scientists at Johns Hopkins and NIDA showed that opiate receptors play a role in cocaine addiction as well. PET scans demonstrated that cocaine addicts showed increased binding activity at mu opiate receptors sites in the brain during active cocaine addiction. Take away the cocaine, and the brain must cope with too many empty dopamine and endorphin receptors. It is also easy to understand the typical symptoms of cocaine and amphetamine withdrawal: lethargy, depression, anger, and a heightened perception of pain. Both the cocaine high and the amphetamine high are easily augmented with cigarettes or heroin. These combinations result in “nucleus accumbens dopamine overflow,” a state of neurochemical super saturation similar to the results obtained with the notorious “speedball”—heroin plus cocaine.

With the arrival of smokable forms of cocaine and amphetamine, the race to pin down the biology of stimulation became even more urgent. Stimulants in smokable form—crack and ice—are even more rapidly addictive for addiction-prone users. “The reason has to do with the hydraulics of the blood supply,” a researcher at the University of Minnesota explained to me. “High concentrations are achieved with each inhalation, and sent right upstairs to the brain—but not all of the brain simultaneously. The target of the flow of blood is the limbic system, whereas the remainder of the brain is exposed to much milder concentrations.”

This extraordinarily concentrated jolt to the reward center is the reason why smokable cocaine and speed are able to pack such a wallop. The entire range of stimulative effects hits the ventral tegmental area and associated reward regions of the brain in seconds, and the focused nature of the impact yields an astonishingly pleasurable high.

But the long-term result is exactly the opposite. It may sound dour and religious, but the scientific fact of the matter is that continuous chemical pleasure extracts its fee in the end: The body’s natural stock of these neurotransmitters starts to fall as the brain, striving to compensate for the artificial flooding of the reward center, orders a general cutback in production. At the same time, the receptors for these neurotransmitters become excessively sensitive due to the frequent, often unremitting nature of the stimulation.

“It’s clear that cocaine causes depletion of dopamine, norepinephrine, serotonin—it is a general neurotransmitter depleter,” said my research source. “That may account for many of the effects we see after someone has stopped using cocaine. They’re tired, they’re lethargic, they sleep; they may be depressed, moody, and so on.” Continued abuse of stimulant drugs only makes the problem worse. One reason why cocaine and amphetamine addicts will continue to use, even in the face of rapidly diminishing returns, is simply to avoid the crushing onset of withdrawal. Even though the drugs may no longer be working as well as they once did, the alternative—the psychological cost of withdrawal—is even worse. In the jargon used by Alcoholics Anonymous, addicts generally have to get worse before they can get better.

When addicts talk about “chasing a high,” the metaphor can be extended to the losing battle of neurotransmitter levels.

[First published September 28, 2011]

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Wednesday, January 7, 2015

Rotting from the Inside

Smoking and the decline of the body. 

We all know smoking is bad for your health. It causes lung cancer and emphysema and contributes to heart disease. But that’s not the end of the list. Recently, Public Health England, a government organization, collected and analyzed research on the contribution smoking makes to other forms of internal body damage. Authored by Dr. Rachael Murray of the UK Centre for Tobacco and Alcohol Studies and the University of Nottingham, the study looked at the correlation between smoking and the musculoskeletal system, the cognitive system, dental health, and vision.

And the results of various meta-analyses are exactly as grim as we might expect. (You can download the PDF HERE.)

Bones, Muscle, and Tissue

Smoking does steady harm to the musculoskeletal system of habitual smokers. Osteoporosis in mature smokers may result from a loss of bone mineral density, a condition for which smoking “is a long established contributing risk factor.” There are a number of ways smoking can affect bone mineral density, says the report, including “decreased calcium absorption, lower levels of vitamin D, changes in hormone levels, reduced body mass, increased free radicals and oxidative stress, higher likelihood of peripheral vascular disease and direct effects of toxic components of tobacco smoke on bone cells.”

Moreover, smoking and broken bones go together like apple pie and ice cream, or in this case, bangers and mash. Overall in the UK, “current smokers have been reported to be at a 25% increased risk of any fracture,” the report concludes. The author notes that the greatest risk for smokers are seen at the hip and the lumbar spine, and women smokers in particular “were at a 17% greater risk of hip fracture at age 60, 41% at 70, 71% at 80 and 108% at 90.” The risk of fracture and the increased bone repair time decreases slowly in former smokers, and it may take 5 to 10 years before abstinent smokers see any statistical benefits.

Researchers have also documented a causal relationship between cigarette smoking and the onset of rheumatoid arthritis. But it is not known whether smoking cessation benefits existing patients with this condition.

As for soft tissue damage, a meta-analysis of 40 studies showed that smoking was associated with “a 33% increased prevalence of low back pain within the previous 12 months, 79% increased prevalence of chronic back pain and 114% increased prevalence of disabling lower back pain” among British smokers. Another study of 13,000 subjects showed that current and ex-smokers experienced up to 60% more pain in the lower back, upper neck and lower limbs than people who had never smoked. Smokers were also “74% more likely than non-smokers to have a rotator cuff tear,” Dr. Murray writes.

The Brain in Your Head

Chronic cigarette smoking hastens the decline in cognitive function that occurs with age. And there is a disturbing link between tobacco smoking and dementia: “A meta-analysis of eight studies published in 2008 reported that current smokers were 59% more likely than never-smokers to suffer Alzheimer’s disease and 35% more likely to suffer vascular dementia.” Earlier studies showed even higher risk percentages. Here, there is the possibility that smoking succession could reduce dementia onset. Two meta-analyses included in the report showed no association between former smoking and risk of dementia.

General cognitive impairment in adults over 50 is “consistently associated” with smoking, according to the UK report. “Faster declines in verbal memory and lower visual search speeds have been reported in male and female smokers aged 43 and 53, with the effect largest in those who smoked more than 20 cigarettes per day, independent of other potentially confounding factors.”

Dental Damage

Smoking is the primary cause of oral cancer, and the risk of developing it is three times less for non-smokers. Smoked and smokeless tobacco are linked to various non-malignant maladies of the soft and hard tissues in the oral cavity. Alcohol is a risk factor for oral cancer as well, “and is almost tripled in alcohol drinkers who smoke.”

Peridontitis, the inflammatory condition marked by bleeding gums and degeneration leading to tooth loss (and an associated greater risk of coronary heart disease) is three to four times as common in adult smokers. And although there are other confounding socioeconomic influences, smoking is also a risk indicator for missing teeth in older smokers and previous smokers. The increased peridontitis risk lasts for several years after smoking cessation.

As for cavities and general tooth decay (caries), “Although the association between smoking and prevalence of dental caries can be attributed to poor dental care and oral hygiene, a cross-section study with a four-year follow-up found that daily smoking independently predicts caries development in smokers.” 

A Dim View

Neovascular and atrophic age-related macular degeneration, the eye conditions that cause a gradual loss of vision, are causally related to cigarette smoking. "A recent meta-analysis reported significant increases in macular degeneration of between 78% and 358%, depending on the study design." Smokers tend to develop the disease ten years earlier than non-smokers, and heavy smokers are at particular risk.

Finally, a number of cohort and case-control studies show a statistically significant link between smoking and cataracts, the cloudy patches over the eye that cause blurred vision. In current smokers, the increased risk is pegged at about 50%. "Smoking cessation reduces risks over time, however, the larger the exposure the longer it takes for the risk to reduce and this risk is unlikely to return to that of a never smoker."

Saturday, January 3, 2015

The Greeks and the Romans on Alcohol

Wine and Beer in Antiquity

"When men drink, then they are rich and successful and win lawsuits and are happy and help their friends. Quickly, bring me a beaker of wine, so that I may wet my mind and say something clever."

"I like best the wine drunk at the cost of others."

"Persians are quite devoted to drinking wine….”                                                                   

“We should not drink like the Carmani… These people, namely, eager to prove their friendship in their drinking bouts, open the veins of the forehead, and mixing the blood which streams down in their wine, they imbibe it, in the belief that to taste each other’s blood is the highest proof of friendship.”

“The wine urges me on, the bewitching wine, which sets even a wise man to singing and to laughing gently and rouses him up to dance and brings forth words which were better unspoken.”

“This is the great evil in wine, it first seizes the feet; it is a cunning wrestler.”

 “Wine prepares the heart for love unless you take too much.”

“Three bowls only do I mix for the temperate—one to health, which they empty first, the second to love and pleasure, the third to sleep. When this is drunk up wise guests go home. The fourth bowl is ours no longer, but belongs to violence; the fifth to uproar, the sixth to drunken reveal, the seventh to black eyes.”
Dionysus, by way of Eubulus

 “The peoples of the Mediterranean began to emerge from barbarism when they learnt to cultivate the olive and the vine.”                                             

 “…the Egyptians became fond of wine and bibulous; and so a way was found among them to help those who could not afford wine, namely, to drink that made from barley; they who took it were so elated that they sang, danced, and acted in every way like persons filled with wine.”


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Tuesday, December 9, 2014

Be Wise and Beware: It's the Holiday Season

Thoughts on addiction, immoderation, and Christmas.

 The Season to be Jolly Careful 
[Paula Goodyer, Sydney Morning Herald]

“More parties, more time with family and less time at work help make Christmas special, but these ingredients can also make it harder for anyone trying to rein in their eating, drinking or drug use….”

Addiction During the Holidays: Recovered or Not, It’s Important to be Prepared 
[Adi Jaffe, Psychology Today]

“The holidays are a stressful time for everyone. Between gift-giving, travel, and keeping up with all parts of the ever-complicated modern family unit, nearly anyone can find themselves driven towards the nearest coping mechanism, whatever that may be….”

Families and Addiction: Surviving the Season of Stress
[Christina Reardon, Social Work Today]

“The holidays usually evoke images of family bliss: —Uncle Joe carving up a big turkey for a traditional family dinner, Aunt Mary bestowing her wonderful gifts, Grandmom sharing cherished stories with the children. The reality is that this dreamy scene usually is nothing more than that—a dream. For many families, the holidays can be a time of great anguish, strife, and overindulgent behavior that is later regretted….”

Addiction and the Holidays
[Danielle B. Grossman, PsychCentral]

“Ah, the holidays: Candy canes, cozy slippers, festive lights, family peace, marital joy, and grateful children. Or not. The holidays are stressful. There are the challenges of too much family, not enough family, not enough money, continual exposure to food and alcohol, and perhaps worst of all, the gap between our actual life and our fantasy life….”

Rehab for the Holidays
[Nic Sheff, The Fix]

“It’s no big revelation to say that the holidays can fucking suck—and that being around family can be stressful as hell….”

Tips for Preventing the Holiday Blues, Staying Sober

“Most people know the holidays can be a period of emotional highs and lows. Loneliness, anxiety, happiness and sadness are common feelings, sometimes experienced in startling succession. The bad news is the holiday blues can trigger relapse for people recovering from alcoholism and other drug addiction. The good news is the blues can be remedied by planning ahead….”

Addiction and Christmas Chaos 
[Candace Plattor, Vancouver Observer]

“Even before Halloween came and went, I noticed that several of my clients were already becoming quite antsy about the upcoming holiday season—for a variety of reasons. People who struggle with addictive behaviors—anything from drugs and alcohol to eating disorders, gambling, sex addiction, or relationship addiction—wondered if they would be able to maintain their sobriety when they began to actually feel the loneliness, fear, and isolation that they had used these behaviors and substances to avoid experiencing….”
The Holidays and “Food Addiction”
[Vicky Hallett, Washington Post]

“If Santa really does stuff his face with every cookie he encounters after shimmying down those chimneys, that explains the big belly. But health and fitness expert Pam Peeke might say Saint Nick's behavior also could be a sign of something commonly found south of the North Pole: food addiction….”

Holiday Season Can Trigger Substance Abuse
[WIBW, Topeka]

“The holiday season is a busy and stressful time. All the festivities - and preparing for them - also can bring a spike in substance abuse. Stormont-Vail West chemical dependency counselor Fiana Martin says alcohol is commonly served at celebrations this time of year. But she says people recovering from addiction don't have to miss out on the fun if they arrive with what she calls a safety plan….”

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Wednesday, December 3, 2014

Cigarettes and Genetic Risk

Evidence From a 4-Decade Study.

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 last year 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.

(First published March 28, 2013)

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

Monday, November 24, 2014

Why Do Patients With Schizophrenia Smoke So Many Cigarettes?

For sound neurological reasons, that's why.

(Originally published May 2, 2012, by The Dana Foundation)

For mental health workers, it is well known that an overwhelming majority of psychiatric patients diagnosed with schizophrenia are heavy cigarette smokers. Surveys have shown that at least 60 percent of patients exhibiting symptoms of schizophrenia are smokers, compared with a national average that hovers just above 20 percent. Writing in the New England Journal of Medicine, researcher Judith J. Prochaska, associate professor of psychiatry at the University of California in San Francisco, found that “smokers with serious mental illnesses are dying 25 years sooner, on average, than Americans overall.” And tobacco is one of the reasons why.

Cigarettes, long familiar in institutional settings as a tool for reinforcing desired behavior, are slowly disappearing from state hospitals. “For state inpatient psychiatric facilities responding to surveys,” says Prochaska, “the best estimate is that about half have adopted smoke-free policies.” Increasingly, acute nicotine withdrawal is a strong part of the mix for the recently admitted smoker with schizophrenia.

An earlier study by Prochaska and colleagues, published in Psychiatric Services, found that while 42 percent of psychiatric patients at a smoke-free San Francisco hospital were smokers, averaging slightly more than a pack per day, none of the smokers received a diagnosis of dependence or withdrawal, and none were offered treatment planning for smoking cessation.

“Smokers who were not given a prescription for nicotine replacement therapy were more than twice as likely to be discharged from the hospital against medical advice as nonsmokers and smokers who were given a prescription for nicotine replacement therapy,” the study concludes. The authors believe that “nicotine withdrawal left unaddressed may compromise psychiatric care…. Given the complicated relationship between mental illness and smoking, integration of cessation efforts into psychiatric care is recommended.”

During the first few hours after patients with schizophrenia enter smoke-free psychiatric emergency settings, more than half become agitated, and 6 percent are physically restrained, according to a recent study by Dr. Michael H. Allen and coworkers at the University of Colorado School of Medicine. Published in the American Journal of Psychiatry, the double-blind study looked at 40 patients admitted to the psychiatric emergency service of the Hospital of the University of Geneva, and found that a relatively safe and simple addition to the emergency stabilization of patients with schizophrenia—a 21 mg nicotine patch—markedly reduced agitation in patients who smoked. The practice of “forced abstinence,” which is the consequence of recent trends toward smoke-free institutions, may not be in the patient’s best interest—especially since formal smoking cessation programs are not always a part of hospital routine.

Allen and colleagues gave out either the nicotine patch or a placebo patch to 40 smokers recently admitted to the hospital with symptoms of schizophrenia. While agitation diminished over time in both the intervention group and the placebo group, “the intervention group had a 33 percent greater reduction in agitation at 4 hours and a 23 percent greater reduction at 24 hours.” The authors say that the differences are similar to those observed in industry trials of common antipsychotics. According to Allen, “forced tobacco abstinence may have the effect of increasing aggressive behavior.” For patients with schizophrenia, smoking works.

The importance of nicotine to patients with schizophrenia should not be underestimated. There are rational biological reasons why schizophrenics smoke. A review of earlier studies published in Psychiatric Services suggests that smokers with schizophrenic symptoms may be self-medicating to improve the processing of auditory stimuli, and to reduce the side-effects caused by common antipsychotic medications. 

“Neurobiological factors provide the strongest explanation for the link between smoking and schizophrenia,” writes Edward R. Lyon, the study’s author, “because a direct neurochemical interaction can be demonstrated.” Flaws in sensory gating, the process by which the brain lowers its response to a repeated sound, are believed to be involved in the auditory hallucinations common to people with schizophrenia. And sensory gating improves for schizophrenics after they load up on nicotine.  Other research has shown a reduction in expression of nicotinic receptors in schizophrenia, suggesting that a susceptibility to smoking and schizophrenia may be related.

Prochaska sees smoking among patients in psychiatric settings as the consequence of several factors, including clinicians' failure to treat nicotine addiction, as well as the role nicotine plays as an antidote to drug side effects. Patients are familiar with the side effects of the drugs they take, “so they smoke and it reduces the blood levels of their medications,” she says. “They’re less sedated, and they can focus more.”

This complicates the picture for psychiatric staff: Antipsychotic drugs are metabolized faster in smokers, leading to the need for higher doses of medication. Prochaska notes that tobacco smoke may inhibit the effect of commonly used drugs like haloperidol, and the inhibition “can be as high as an increase clearance of 40–98 percent for olanzapine, a costly medication.”

In an interview, Prochaska said that the heaviest smokers “may need to stay on cessation medications for an extended period, and that’s certainly better for them than smoking. Combination therapy also is recommended. In our studies, we combine the nicotine patch with gum or lozenge so they’re able to add to the patch to get sufficient coverage of withdrawal symptoms.”

Mental health professionals have traditionally argued that patients with schizophrenia do not want to quit smoking, but Prochaska’s work suggests otherwise. Patients in psychiatric settings are about as likely as the general population to want to quit smoking, her research shows. “There is growing evidence that smokers with mental illness are as ready to quit as other smokers and can do so without any threat to their mental health recovery,” she said.

By some estimates, people with psychiatric disorders make up almost half of the current U.S. market for tobacco products. As Prochaska has written, “nicotine dependence is the most prevalent substance use disorder among adult psychiatric patients, and it needs to be placed on the radar of psychiatric practice.”

It’s up to healthcare providers to get the ball rolling. “Many facilities are still struggling with it,” she says. “It’s not been in their purview traditionally, so changing the culture is a big piece of the solution. It’s very much a matter of trying to get tobacco treatment medicalized, having it be automatic, so that nicotine replacement is right there in the admitting orders. And ideally, working with patients while they are hospitalized to motivate smoking cessation, and supporting them when they leave.”

Tuesday, November 18, 2014

Another Look at Acamprosate

The most popular pharmaceutical treatment for alcoholism, explained.

(First published February 17, 2014)

“Occasionally,” reads the opening sentence of a commentary published online earlier this year in Neuropsychopharmacology, “a paper comes along that fundamentally challenges what we thought we knew about a drug mechanism.” The drug in question is acamprosate, and the mechanism of action under scrutiny is the drug’s ability to promote abstinence in alcoholics. The author of the unusual commentary is Markus Heilig, Chief of the Laboratory of Clinical and Translational Studies at the National Institute on Alcohol Abuse and Alcoholism (NIAAA).

Acamprosate, in use worldwide and currently the most widely prescribed medication for alcohol dependence in the U.S., may work by an entirely different mechanism than scientists have believed on the basis of hundreds of studies over decades. Rainer Spanagel of the Institute of Psychopharmacology at the University of Heidelberg, Germany, led a large research group in revisiting research that he and others had performed on acamprosate ten years earlier. In their article   for Neuropsychopharmacology, Spanagel and coworkers concluded that a sodium salt version of acamprosate was totally ineffective in animal models of alcohol-preferring rats.

“Surprisingly,” they write, “calcium salts produce acamprosate-like effects in three animal models…. We conclude that N-acetylhomotaurinate is a biologically inactive molecule and that the effects of acamprosate described in more than 450 published original investigations and clinical trials and 1.5 million treated patients can possibly be attributed to calcium.”

At present, the Food and Drug Administration (FDA] has approved three drugs for alcoholism— Antabuse, naltrexone, plus acamprosate in 2004. In addition, there is considerable clinical evidence behind the use of four other drugs—topiramate, baclofen, ondansetron, and varenicline. Acamprosate as marketed is the calcium salt of N-acetyl-homotaurinate, a close relative of the amino acid taurine. It has also been found effective in European studies.

What did scientists think acamprosate was doing? Various lines of research had linked acamprosate to glutamate transmission. Changes in glutamate transmission have been directly implicated in active alcoholism. A decade ago, the Spanagel group had decided that acamprosate normalized overactive glutamate systems, and hypothesized that acamprosate was modulating GABA transmission. So it became known as a “functional glutamate antagonist.”  But specific mechanisms have remained elusive ever since.

Now, as Heilig comments, “the reason it has been difficult to pin down the molecular site of acamprosate action may simply be because it does not exist. Instead, the authors propose that the activity attributed to acamprosate has all along reflected actions of the Ca++ it carries.” As the researcher paper explains it: “N-acetylhomotaurinate by itself is not an active psychotropic molecule…. We have to conclude that the proposed glutamate receptor interactions of acamprosate cannot sufficiently explain the anti-relapse action of this drug.” Further work shows that acamprosate doesn’t interact with glutamate binding sites at all.  In other words, calcium appears to be the major active ingredient in acamprosate. Animal studies using calcium chloride or calcium gluconate reduced alcohol intake in animals at rates similar to those seen in acamprosate, the researchers claim.

Subsequently, the researchers revisited the earlier clinical studies, subjected them to secondary analysis, and concluded that “in acamprosate-treated patients positive outcomes are strongly correlated with plasma Ca++ levels. No such correlation exists in placebo-treated patients.” In addition, calcium salts delivered via different carrier drugs replicated the suppression of drinking in the earlier animal findings.

Where there cues pointing toward calcium? The researchers conclude that “calcium sensitivity of the synapse is important for alcohol tolerance development, calcium given intraventricularly significantly enhances alcohol intoxication in a dose-dependent manner,” and “activity of calcium-dependent ion channels modulate alcohol drinking.”

Interestingly, in the late 50s and early 60s, there was a brief period of interest in calcium therapy for the treatment of alcoholism. In 1964, the Journal of Psychology ran an article titled “Intensive Calcium Therapy as an Initial Approach to the Psychotherapeutic Relationship in the Rehabilitation of the Compulsive Drinker.” Now it appears possible that a daily dose of acamprosate is effective for some abstinent alcoholics because it raises calcium plasma levels. Calcium supplements may be in for a round of intensive clinical testing if these findings hold up.

The authors now call for “ambitious randomized controlled clinical trials,” to directly compare “other means of the Ca++ delivery as an approach to treat alcohol addiction. Data in support of a therapeutic role of calcium would open fascinating clinical possibilities.”  Indeed it would.

Spanagel R., Vengeliene V., Jandeleit B., Fischer W.N., Grindstaff K., Zhang X., Gallop M.A., Krstew E.V., Lawrence A.J. & Kiefer F.  (2013). Acamprosate Produces Its Anti-Relapse Effects Via Calcium, Neuropsychopharmacology, 39 (4) 783-791. DOI: 10.1038/npp.2013.264

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