Archive for March, 2010

Common mechanisms of drug abuse and obesity

Some of the same brain mechanisms that fuel drug addiction in humans accompany the emergence of compulsive eating behaviors and the development of obesity in animals, according to research funded by the National Institute on Drug Abuse (NIDA), a component of the National Institutes of Health.

The study, conducted by researchers at the Scripps Research Institute, was released today in the online version of Nature Neuroscience and will also appear in the journal’s May 2010 print issue. When investigators gave rats access to varying levels of high-fat foods, they found unrestricted availability alone can trigger addiction-like responses in the brain, leading to compulsive eating behaviors and the onset of obesity.

Addiction and Obesity

“Drug addiction and obesity are two of the most challenging health problems in the United States,” said Dr. Nora D. Volkow, director of NIDA. “This research opens the door for us to apply some of the knowledge we have gathered about drug addiction to the study of overeating and obesity.”

Both obesity and drug addiction have been linked to a dysfunction in the brain’s reward system. In both cases overconsumption can trigger a gradual increase in the reward threshold—requiring more and more palatable high fat food or reinforcing drug to satisfy the craving over time.

Researchers conducted this study in three groups of male rats over a 40-day period. Each day, the three groups had unlimited access to standard lab food. In addition, two of the groups also had access to high-fat, cafeteria style foods for short (one-hour) or long (18-23 hours) periods.

After 40 days, all groups were denied access to the high-fat foods. Throughout the study, researchers observed the feeding behaviors of each group, noting caloric intake, weight gain, and brain response.

The results support the notion that type 2 dopamine receptors (D2DR)—brain receptors that have been shown to play a key role in addiction—also play a key role in the rats’ heightened response to food. In fact, as the rats became obese, the levels of D2DR in the brain’s reward circuit decreased. This drop in D2DR is similar to that previously seen in humans addicted to drugs like cocaine or heroin.

Insight Into Obesity

“The results of this study could provide insight into a mechanism for obesity,” said Paul J. Kenny, one of the study’s co-authors and an associate professor at the Scripps Jupiter, Fla., research facility. “It’s possible that drugs developed to treat addiction may also benefit people who are habitual overeaters.”

Study results also suggest that environmental factors, such as increased or unlimited access to high-fat food options, can contribute to the problem of obesity.

“Hopefully, this study will change the way people think about eating,” said Paul Johnson, a co-author and graduate student in the department of molecular therapeutics. “It demonstrates how just the availability of food can trigger overconsumption and obesity.”

March 31st, 2010  in Substance Abuse No Comments »

Teenagers programmed to take risks

In research published in the journal Cognitive Development, children, adolescents and adults aged 9-35 years chose between risky and safe options in a computer gambling game. Scientists found that the teenagers took the most risks compared with the other groups, with the most risky behavior seen in 14-year olds.

The results suggest that teenagers are good at weighing up the pros and cons of their decisions (unlike children) but take risks because they enjoy the thrill of a risky situation more than other age groups – especially when they have a ‘lucky escape’.

Choosing to Take Risks

“The reason that teenagers take risks is not a problem with foreseeing the consequences. It was more because they chose to take those risks,” said Dr Stephanie Burnett from the UCL Institute of Cognitive Neuroscience, and the lead author.

“This is the first evidence from a lab-based study that adolescents are risk-takers. We are one step forward in determining why teenagers engage in extremely risky behaviors such as drug use and unsafe sex,” she added.

The study involved 86 boys and men who were asked to play computer games, during which they made decisions in order to win points. After each game scientists measured the participants’ emotional response by recording how satisfied or dissatisfied they were with the outcome.

They found that the onset of the teenage years marked an increase in how much enjoyment resulted from winning in a ‘lucky escape’ situation. This could help explain why teenagers are more likely to take bigger risks.

Risky Activities During Teens

“The onset of adolescence marks an explosion in ‘risky’ activities – from dangerous driving, unsafe sex and experimentation with alcohol, to poor dietary habits and physical inactivity. This contributes to the so-called ‘health paradox’ of adolescence, whereby a peak in lifetime physical health is paradoxically accompanied by high mortality and morbidity.

“Understanding why adolescents take such risks is important for public health interventions and for families,” said Dr Sarah-Jayne Blakemore, also from the UCL Institute for Cognitive Neuroscience, and co-author of the research.

TigerDirect

March 26th, 2010  in Alcohol No Comments »

Risky drinkers less likely to seek medical care

Women and men who engage in frequent heavy drinking report significantly worse health-related practices, according to a Kaiser Permanente Center for Health Research study in the journal Addiction Research & Theory.

For the study, researchers surveyed 7,884 members of the Kaiser Permanente Northwest integrated health plan in Oregon and Washington. They found that risky drinkers have attitudes and practices that may adversely affect their long-term health and that people who drink at hazardous levels were less likely than other categories of drinkers to seek routine medical care.

At-Risk Drinkers

Risky drinking was defined in three different ways to account for both short and long-term alcohol-related risks: 1) those who, on average, drank three or more drinks per day, 2) women who consumed four or more drinks during one sitting, or men who drank five or more drinks during one sitting, or 3) people identified as at-risk drinkers using a commonly used screening tool.

“The main finding here is that risky drinkers also engage in other behaviors–such as relieving stress with alcohol and cigarettes, not wearing seatbelts, unhealthy eating and not regularly seeing their doctors–that put their health at risk,” said study lead author Carla Green, a senior investigator at the Kaiser Permanente Center for Health Research. “Physicians should not only be concerned about patients’ heavy drinking, but also these other health-related practices.”

The study, funded by the National Institute on Alcohol Abuse and Alcoholism, is the first to examine the relationship between drinking patterns and health while taking into account a wide-range of other factors that might influence that relationship.

Drinking Patterns and Health

Those factors include diet, exercise, stress management, sleep practices, seat belt use, income, education, obesity, as well as feelings about seeing the doctor, skepticism toward medical care, and attitudes about personal ability to influence health.

“Our study found that men and women who drank the most had less collaborative relationships with their doctors and were more likely to dislike going to the doctor. They were also less confident they could change their own health-related practices and more likely to think health is a matter of good fortune,” Green said.

While the study clearly showed a negative relationship between health and daily, heavy drinking, it also found that moderate drinking was associated with better health. In fact, on a standard health status survey, people who drank one-to-three drinks daily reported slightly better health than all other categories of drinkers, including life-long abstainers, former drinkers, light drinkers (less than one drink a day) and heavier drinkers (three or more drinks per day). People who drank moderately were also more likely to have better health-related attitudes and practices, and more likely to seek routine medical care.

Moderate Drinkers Healthier

“Even after taking these other health-related attitudes and practices into account, there was still a small but independent relationship between moderate drinking and better self-assessed health,” said Michael Polen, study co-investigator at the Kaiser Permanente Center for Health Research. “Previous research has linked moderate alcohol drinking with cardiovascular benefits, so that might be the underlying reason moderate drinkers report better health. It’s also possible that there are additional factors we didn’t measure that account for this positive relationship.”

The study was conducted by reviewing mail-survey responses of 7,884 Kaiser Permanente members from 2002 and 2003. The survey was linked to two years of electronic health records and service use data to study how drinking patterns affect willingness to seek health care. Each of the members, aged 18 to 64, responded to a survey that measured physical and mental health as well as health-related attitudes and practices.

March 24th, 2010  in Alcoholism No Comments »

Proteins may point to alcohol use test

Measuring a set of protein changes in the blood linked to alcohol use may potentially lead to a more accurate diagnostic test than those currently available, according to Penn State College of Medicine researchers.

“The challenge in alcohol abuse as opposed to substance abuse — things like cocaine or heroin or PCP — is that alcohol is a perfectly legal substance for those over 21,” said Willard M. Freeman, Ph.D., department of pharmacology and lead investigator. “Unlike routine testing for illicit drugs, you can’t just look for a trace of alcohol because many people enjoy a drink in a responsible manner and alcohol is very quickly metabolized. Discriminating between excessive and responsible levels of drinking makes this a greater challenge.”

Proteins Predict Alcohol Use

Penn State Hershey researchers, working for two-and-a-half years in cooperation with Kathleen A. Grant, Ph.D., at the Oregon National Primate Research Center, identified a set of 17 proteins in the blood that accurately predicted alcohol usage 90 percent of the time in non-human primates. Researchers were able to separate usage into three categories — no alcohol use, drinking up to two drinks per day and drinking at least six drinks per day.

Protein levels rose and declined depending on alcohol consumption.

“We observed that the levels of some proteins increased or decreased with as little as one or two drinks a day,” Freeman said. “These same changes occurred with heavier levels of drinking. We also found other proteins that responded only to heavy levels of drinking. Combined, these proteins allow us to classify subjects into non-drinking, alcohol-using, and alcohol-abusing groups.”

The researchers are continuing their work, first by determining whether the changes measured return to normal levels with cessation of drinking. Second, they are looking for additional proteins to both increase accuracy and provide alternates if some of the initial 17 do not work in humans.

Working with groups around the world, Penn State Hershey researchers — led by Freeman and Kent Vrana, chair, department of pharmacology — plan to collect blood from people undergoing inpatient treatment for alcohol abuse.

Testing for Abstinence

“We’ll collect blood throughout their stay to see if the patients’ protein pattern reverts from an excessive drinking pattern to a pattern that’s indicative of alcohol abstinence,” Freeman said.

The goal is to create a diagnostic test for alcohol consumption that may be used in areas of public safety like aviation or national security, for parole conditions and for helping physicians determine if a patient may have an alcohol abuse problem. Currently there are tests that try to address this issue, but Freeman said these tests are not sensitive and specific enough to serve as diagnostics.

“Many of these tests rely on just one protein,” he said. “The limitation to this approach is that these tests often look at proteins produced by the liver. While these proteins increase with excessive alcohol intake, they also increase with any type of injury to the liver. For example, a lot of prescription drugs are hard on the liver. These tests let us know that the liver is being stressed but can’t discriminate between excessive drinking and other conditions, which therefore reduces the utility of these tests.

“That’s where we see the promise in this panel of proteins. The proteins are produced by a number of organs including the liver, the muscle, and the brain. This unique fingerprint that is indicative of alcohol abuse is less likely to be produced by unrelated conditions.”

Freeman stresses, a diagnostic test would not be testing for alcoholism, but rather, alcohol intake.

Amount of Drinking Test

“In a strictest use of the words, alcoholism is a psychological diagnosis as opposed to a level of drinking,” he said. “The Diagnostic and Statistical Manual really classifies alcohol abuse and alcoholism based on how alcohol is interfering with your life. Obviously we can’t use a blood test to say yes, your drinking is interfering with your home life. But the amount of drinking and the amount of problems it causes in your life are tightly correlated.

“We envision, a number of years down the line if this becomes a diagnostic test, that if the test indicates that you’re drinking a lot, it would prompt a referral to a specialist in alcohol abuse and alcoholism. This test could provide an objective indicator to help people begin addressing what may really be a problem in their lives.”

March 24th, 2010  in Alcohol No Comments »

Older nonsmokers gain most from tobacco ban

Older people who have never smoked benefit most from smoking bans, a study suggests.

A study in New Zealand showed that, three years after a smoking ban on all workplaces was introduced, hospital admissions for heart attacks among men and women aged 55-74 fell by 9 per cent. This figure rose to 13 per cent for 55-74 year olds who had never smoked.

Overall, the research showed heart attacks among people aged 30 and over fell by an average of 5 per cent in the three years following the ban.

The study, involving scientists from the University of Edinburgh, examined trends in acute heart attacks following a change in legislation. The ruling, which updates a previous law in which smoking was outlawed in some public places, makes smoking illegal in all workplaces including bars and restaurants.

Fewer Heart Attacks

Researchers also found that heart attacks were reduced for ex-smokers of all ages, and that there was a greater decrease in hospital admissions for men compared with women.

In addition, the study found that people in more affluent neighbourhoods benefited more from the ban than those in poorer areas. This may be because they visit cafes and restaurants more often or because they are more likely to use the smoking ban as an incentive to quit.

Dr Jamie Pearce, of the University of Edinburgh’s School of GeoSciences, who took part in the study, said: “This short-term research indicates a link between a smoking ban in bars and restaurants and a reduction in severe heart attacks. However, more work is needed to look at the effects of the ban in greater detail.”

The study, carried out with the Universities of Otago and Canterbury in New Zealand and the University of Southampton, was published in the Australian and New Zealand Journal of Public Health.


March 18th, 2010  in Tobacco No Comments »

Smoking, but not past alcohol abuse, may impair mental function

Men and women with a history of alcohol abuse may not see long-term negative effects on their memory and thinking, but female smokers do, a new study suggests.

In a study of 287 men and women ages 31 to 60, researchers found that those with past alcohol-use disorders performed similarly on standard tests of cognitive function as those with no past drinking problems.

The findings were not as positive when it came to tobacco, however.

Cognitive Function Impaired

In general, women who had ever been addicted to smoking had lower scores on certain cognitive tests than their nonsmoking counterparts. The same pattern was not true of men, however, the researchers report in the Journal of Studies on Alcohol and Drugs.

The reasons for the disparate findings on alcohol and smoking are not fully clear. Nor do they necessarily mean that serious alcohol problems would not affect long-term memory and other cognitive abilities; most study participants who had ever had drinking problems met the criteria for alcohol abuse rather than the more serious diagnosis of dependence.

Alcohol abuse was diagnosed when people reported one symptom of problem drinking — drinking and driving, for instance, or failing to meet work or school obligations as a result of drinking. Dependence, on the other hand, required people to have at least three symptoms — such as needing to drink more and more to achieve the same effects and experiencing physical withdrawal symptoms when they did not drink.

Alcoholics Not ‘Doomed’

If more study participants had been alcohol dependent, the findings on cognition might have been different, says lead researcher Dr. Kristin Caspers, an assistant research scientist in the department of psychiatry at the University of Iowa in Iowa City.

But the bottom line, she says, is that people with a history of alcohol abuse appear not to be “doomed” to suffer cognitive effects when current levels of drinking are in the light to moderate range.

The findings are based on assessments of 115 men and 169 women with an average age of 43. Overall, 45 percent of men and 37 percent of women met the criteria for lifetime alcohol abuse, and 13 percent and nearly 4 percent, respectively, had a lifetime history of alcohol dependence. One quarter of women and 18 percent of men had a history of tobacco dependence.

Overall, women who reported having ever smoked 20 or more cigarettes a day scored lower than nonsmokers on tests of executive function — that is, “higher-order” brain functions that include the ability to reason, plan and organize. The scores were, however, all within normal range.

Estrogen a Factor?

As for why smoking was related to cognitive scores only among women, it’s possible that there is a role for estrogen, according to Caspers.

Animal research suggests that nicotine lowers blood estrogen levels and may inhibit the positive effects of the hormone on brain cells. Sixty percent of the women in the current study were between the ages of 40 and 54, when menopause usually occurs. In theory, nicotine may exacerbate any brain-cell effects of fluctuating estrogen levels in women as they age, the researchers speculate.

March 16th, 2010  in Tobacco No Comments »

R-rated movies increase likelihood of underage drinking

R-rated movies portray violence and other behaviors deemed inappropriate for children under 17 year of age. A new study finds one more reason why parents should not let their kids watch those movies: adolescents who watch R-rated movies are more likely to try alcohol at a young age.

Published in Prevention Science, a scientific journal of the Society for Prevention Research, the study of 6,255 children examined the relationship between watching R-rated movies and the probability of alcohol use across different levels of “sensation seeking,” which is a tendency to seek out risky experiences.

Sensation Seeking

The study was funded by the National Institute on Alcohol Abuse and Alcoholism and conducted by James D. Sargent, MD, a pediatrician at Dartmouth Medical School. The children were surveyed every 8 months for a period of two years from 2003 through 2005.

“The study found that watching R-rated movies affected the level of sensation seeking among adolescents. It showed that R-rated movies not only contain scenes of alcohol use that prompt adolescents to drink, they also jack up the sensation seeking tendency, which makes adolescents more prone to engage in all sorts of risky behaviors” Sargent said.

“There is another take home point in the findings. When it comes to the direct effect on alcohol use, the influence of R-rated movies depends on sensation seeking level. High sensation seekers are already at high risk for use of alcohol, and watching a lot of R-rated movies raises their risk only a little. But for low sensation seekers, R-rated movies make a big difference. In fact, exposure to R-rated movies can make a low sensation seeking adolescent drink like a high sensation seeking adolescent.” Sargent explained.

The Dartmouth pediatrician said that one possible explanation is high sensation seeking adolescents tend to get their experiences out on the street. They hang around other high sensation seekers, who are also engaging in risky behaviors, so there is less room for movies to make a difference in their risk for alcohol use.

R-Rated Movies and Alcohol

“The message to parents is clear. Take the movie ratings literally. Under 17 should not be permitted to see R-rated movies,” Sargent said.

The study was based on telephone surveys of 6,522 adolescents aged 10-14 years. Parental consent and adolescent consent was obtained prior to interviewing each respondent. To protect confidentiality, adolescents indicated their answers to sensitive questions by pressing numbers on the telephone, rather than speaking aloud. The study sample mirrored the U.S. adolescent population with respect to age, sex, household income and census region, but with a slightly higher percentage of Hispanics and a slightly lower percentage of Blacks.

Sensation seeking was based on how individual subjects identified with statements like: “I like to do scary things, I like to do dangerous things, I often think there is nothing to do, and I like to listen to loud music.” Adolescents were also asked if they had ever tried alcohol that their parents were not aware of. This excluded adolescents who initiated drinking with sips of alcohol provided by parents. R-rated movie watching was measured by asking respondents if they had watched a random selection of movie titles drawn from box office hits during 2003 that had grossed at least $15 million. The movie titles included movies that had G (general audience), P/G (parental guidance) and R (restricted) ratings.

March 13th, 2010  in Alcohol No Comments »

New insight on how fast nicotine peaks in the brain

Nicotine takes much longer than previously thought to reach peak levels in the brains of cigarette smokers, according to new research conducted at Duke University Medical Center.

Traditionally, scientists thought nicotine inhaled in a puff of cigarette smoke took a mere seven seconds to be taken up by the brain, and that each puff produced a spike of nicotine. Using PET imaging, Duke investigators illustrate, for the first time, that cigarette smokers actually experience a steady rise of brain nicotine levels during the course of smoking a whole cigarette.

The findings, scheduled to appear online in the Early Edition of Proceedings of the National Academy of Sciences (PNAS), could lead to more effective treatments for smoking addiction.

Nicotine Accumulates in the Brain

“Previously it was thought that the puff-by-puff spikes of nicotine reaching the brain explained why cigarettes are so much more addictive than other forms of nicotine delivery, like the patch or gum,” says Jed Rose, Ph.D., director of the Duke Center for Nicotine and Smoking Cessation Research. “Our work now calls into question whether addiction has to do with the puff-by-puff delivery of nicotine. It may actually depend in part on the overall rate at which nicotine reaches and accumulates in the brain, as well as the unique habit and sensory cues associated with smoking.”

Yet, when the researchers compared 13 dependent smokers to 10 non-dependent smokers, they were surprised to find the dependent smokers had a slower rate of nicotine accumulation in the brain. “This slower rate resulted from nicotine staying longer in the lungs of dependent smokers, which may be a result of the chronic effects of smoke on the lungs,” surmises Rose.

The difference in rate of nicotine accumulation in the brain doesn’t explain why some people become addicted to cigarettes and others don’t. “Even if you correct for the speed of delivery, our study showed the non-dependent smokers eventually experienced the same high levels of nicotine in their brain as dependent smokers, yet they did so without becoming dependent. The real mystery is why.”

Sensitivity to Nicotine

Rose says the absence of addiction in these smokers could be due to genetic differences, differences in the way they smoke, or differences in the psychological effects they derive. “We’re still not able to fully explain why these people are able to smoke without becoming addicted.”

Despite the questions raised, the study provides important insights into the role of the speed and level of brain nicotine levels, and which receptors in the brain are at work. “Different receptors respond to nicotine at different levels of sensitivity,” says Rose. “Knowing the levels of nicotine that are really getting to the brain gives us clues as to which receptors are more likely to be important for the dependence-producing effects of cigarette smoking.”

March 9th, 2010  in Tobacco No Comments »

Warning to parents: Look for signs of K2

In the last month, Anthony Scalzo, M.D., professor of toxicology at Saint Louis University, has seen nearly 30 cases involving teenagers who were experiencing hallucinations, severe agitation, elevated heart rate and blood pressure, vomiting and, in some cases, tremors and seizures. All of these teens had smoked a dangerous, yet legal substance known as K2 or “fake weed.”

According to Scalzo, K2, an unregulated mixture of dried herbs, is growing in popularity because it is legal, purported to give a high similar to marijuana and believed to be natural and therefore safe.

Many Adverse Effects

“K2 may be a mixture of herbal and spice plant products, but it is sprayed with a potent psychotropic drug and likely contaminated with an unknown toxic substance that is causing many adverse effects. These toxic chemicals are neither natural nor safe,” said Scalzo, who also directs the Missouri Regional Poison Control Center at SSM Cardinal Glennon Children’s Medical Center.

What makes K2 so dangerous? Further testing is needed, but Scalzo says the symptoms, such as fast heart beat, dangerously elevated blood pressure, pale skin and vomiting suggest that K2 is affecting the cardiovascular system of users. It also is believed to affect the central nervous system, causing severe, potentially life-threatening hallucinations and, in some cases, seizures.

While JWH 018, a synthetic man-made drug, similar to cannabis, may be responsible for the hallucinations, Scalzo suspects that there is another unknown toxic chemical being sprayed on K2.

Mixture is Not ‘Natural’

K2, also known as “spice,” has been sold since 2006 as incense or potpourri. It sells for approximately $30 to $40 per three gram bag, which is comparable in cost to marijuana, and is available over the Internet.

“K2 use is not limited to the Midwest; reports of its use are cropping up all over the country. I think K2 is likely a bigger problem than we’re aware of at this time,” Scalzo said.

Legislators in Missouri currently are considering a proposed ban of K2, which Scalzo supports. In the meantime, he says that parents should be on the lookout for warning signs such as agitation, pale appearance, anxiety or confusion due to hallucinations.

“Look for dried herb residues lying around your kids’ room. Chances are they are not using potpourri to make their rooms smell better or oregano to put on their pizza,” Scalzo said.

March 8th, 2010  in Substance Abuse 1 Comment »

Cocaine-related deaths rise in warm weather

In a study published in the journal Addiction, researchers in the United States have discovered that accidental overdose deaths involving cocaine rise when the average weekly ambient temperature passes 24 degrees Celsius (75 degrees Fahrenheit). Using mortality data from New York City’s Office of the Chief Medical Examiner for 1990 through 2006, and temperature data from the National Oceanic and Atmospheric Association, researchers found that accidental overdose deaths that were wholly or partly attributable to cocaine use rose significantly as the weekly ambient temperature passed 24 degrees Celsius. The number of cocaine-related overdose deaths continued to rise as temperatures continued to climb.

Cocaine Increases Body Temperature

Cocaine-related overdose deaths increase as the ambient temperature rises because cocaine increases the core body temperature, impairs the cardiovascular system’s ability to cool the body, and decreases the sense of heat-related discomfort that ordinarily motivates people to avoid becoming overheated. Cocaine users who become overheated (hyperthermic) can overdose on lower amounts of cocaine because their bodies are under more stress.

The study’s findings correct previous research that associated an increase in cocaine-related mortality with much higher temperatures (31.1 degrees Celsius, or 87.9 degrees Fahrenheit). Because cocaine-related overdose fatalities begin to rise at lower ambient temperatures than was previously thought, it is now apparent that cocaine users are at risk for longer periods of each year. Between 1990 and 2006, the average weekly temperature in New York City rose above 24 degrees Celsius for about seven weeks per year.

Deaths Linked to Temperature Rise

The study showed no difference in the number of drug overdoses in New York City among those weeks where the average temperature was between -10 and 24 degrees Celsius. Above 24 degrees Celsius, however, there were 0.25 more drug overdoses per 1,000,000 residents per week for every two degrees increase in weekly average temperature. Given that over 8.2 million people live in New York City, the study’s findings predict that at least two more people per week will die of a drug overdose in the city for each two degree rise in temperature above 24 degrees Celsius, compared to weeks with average temperatures of 24 degrees and below.

The authors of this study point out the need for public health interventions in warm weather, such as delivering health-related warnings to high-risk groups. Prevention efforts could also include making air conditioning available in locations where cocaine use is common such as urban areas with a known high prevalence of cocaine use, and within those urban areas, particular neighbourhoods with elevated numbers of cocaine-related deaths or arrests. As lead author Dr. Amy Bohnert explains, “Cocaine users are at a high risk for a number of negative health outcomes and need public health attention, particularly when the weather is warm.”

March 3rd, 2010  in Illegal Drugs No Comments »