Posts tagged smoking
Articles and news from the latest research reports.
Neural reward response may demonstrate why quitting smoking is harder for some
For some cigarette smokers, strategies to aid quitting work well, while for many others no method seems to work. Researchers have now identified an aspect of brain activity that helps to predict the effectiveness of a reward-based strategy as motivation to quit smoking.
The researchers observed the brains of nicotine-deprived smokers with functional magnetic resonance imaging (fMRI) and found that those who exhibited the weakest response to rewards were also the least willing to refrain from smoking, even when offered money to do so.
"We believe that our findings may help to explain why some smokers find it so difficult to quit smoking," said Stephen J. Wilson, assistant professor of psychology, Penn State. "Namely, potential sources of reinforcement for giving up smoking — for example, the prospect of saving money or improving health — may hold less value for some individuals and, accordingly, have less impact on their behavior."
The researchers recruited 44 smokers to examine striatal response to monetary reward in those expecting to smoke and in those who were not, and the subsequent willingness of the smokers to forego a cigarette in an effort to earn more money.
"The striatum is part of the so-called reward system in the brain," said Wilson. "It is the area of the brain that is important for motivation and goal-directed behavior — functions highly relevant to addiction."
The participants, who were between the ages of 18 and 45, all reported that they smoked at least 10 cigarettes per day for the past 12 months. They were instructed to abstain from smoking and from using any products containing nicotine for 12 hours prior to arriving for the experiment.
Each participant spent time in an fMRI scanner while playing a card-guessing game with the potential to win money. The participants were informed that they would have to wait approximately two hours, until the experiment was over, to smoke a cigarette. Partway through the card-guessing task, half of the participants were informed that there had been a mistake, and they would be allowed to smoke during a 50-minute break that would occur in another 16 minutes.
However, when the time came for the cigarette break, the participant was told that for every 5 minutes he or she did not smoke, he or she would receive $1 — with the potential to earn up to $10.
Wilson and his colleagues reported in a recent issue of Cognitive, Affective and Behavioral Neuroscience that they found that smokers who could not resist the temptation to smoke also showed weaker responses in the ventral striatum when offered monetary rewards while in the fMRI.
"Our results suggest that it may be possible to identify individuals prospectively by measuring how their brains respond to rewards, an observation that has significant conceptual and clinical implications," said Wilson. "For example, particularly ‘at-risk’ smokers could potentially be identified prior to a quit attempt and be provided with special interventions designed to increase their chances for success."
One third of all brain aneurysms rupture: the size is not a significant risk factor
Approximately one third of all brain aneurysms rupture during a patient’s lifetime, resulting in a brain haemorrhage. A recent Finnish study demonstrates that, unlike what was previously assumed, the size of the aneurysm does not significantly impact the risk of rupture.
(Image credit: Miikka Korja)
The new Finnish study established that approximately one third of all aneurysms and up to one fourth of small aneurysms will rupture during a patient’s lifetime. The lifetime risk for rupture of a brain aneurysm depends heavily on the patient’s overall load of risk factors.
The risk of rupture is particularly high for female smokers with brain aneurysms of seven millimetres or more in diameter.
What surprised the researchers most was that the size of an aneurysm had little impact on its risk for rupture, particularly for men, despite a previously presumed correlation. In addition, the risk of rupture among non-smoking men was exceptionally low.
This is not to say that aneurysms in non-smoking men never rupture, but that the risk is much lower than we previously thought. This means treating every unruptured aneurysm may be unnecessary if one is discovered in a non-smoking man with low blood pressure, says Docent Seppo Juvela, University of Helsinki.
The study, published in Stroke 22nd May, is unique in that it monitored aneurysm patients over their entire lifetimes, whereas typical follow-up studies last only between one and five years in duration. The study is also exceptionally broad in scope.
It is unlikely that another similar, non-selected lifetime follow-up study on aneurysm patients will ever be conducted again, Juvela states.
Current care practices are based largely on the results of previous, shorter studies. Such studies have shown that the size of the aneurysm is the most significant factor predicting its risk for rupture. Consequently, small aneurysms have often been left untreated.
It is difficult to conduct reliable epidemiological research in brain aneurysms. The past 10–15 years have seen a distortion in the field due to a very limited group of researchers determining the direction for research. Now the situation is clearly changing, and clinically reasonable, population-based studies using non-selected data are on the rise again, states Docent Miikka Korja of the HUCS neurosurgery clinic.
(Source: uutiset.helsinki.fi)
Smoking’s toll on mentally ill analyzed
Those in the United States with a mental illness diagnosis are much more likely to smoke cigarettes and smoke more heavily, and are less likely to quit smoking than those without mental illness, regardless of their specific diagnosis, a new study by researchers from the Yale School of Medicine shows.
They also found variations in smoking rates and likelihood of quitting among different diagnoses of mental illness. The results are reported in the April issue of the journal Tobacco Control.
Thirty-nine percent of adults with a psychiatric diagnosis smoked compared to 16% without a diagnosis, according to data from the National Epidemiologic Survey on Alcohol and Related Conditions analyzed by researchers. Two out of every three people with drug use disorder smoke, compared to one out of three with social phobia.
“We know that smokers with mental illness are more susceptible to smoking-related disease, and those with mental illness die 25 years earlier than adults without mental illness,” said Sherry McKee, associate professor of psychiatry, and senior author on the study. “Effective smoking cessation treatments are available and we know that smokers with mental illness can quit smoking. We need to address why smokers with mental illness are not being treated for their smoking.”
Over the three-year study period, 22% of smokers with no psychiatric disorders were able to quit smoking, whereas rates of quitting among those with psychiatric disorders were 25% lower. Rates of quitting were lowest among those with dysthymia (10%), agoraphobia (13%), and social phobia (13%). “We also found that individuals with multiple diagnoses had the lowest quit rates,” added Philip Smith, lead author on the study.
This study adds to evidence that smokers with mental illness consume nearly half of all cigarettes in the United States, despite making up a substantially smaller proportion of the population.
Researchers and policymakers are increasingly calling attention to this important public health issue, and this study helps point to a need for interventions and policy that directly help individuals with mental illness quit smoking.
Smoking may dull obese women’s ability to taste fat and sugar
Cigarette smoking among obese women appears to interfere with their ability to taste fats and sweets, a new study shows. Despite craving high-fat, sugary foods, these women were less likely than others to perceive these tastes, which may drive them to consume more calories.
M. Yanina Pepino, PhD, assistant professor of medicine at Washington University School of Medicine in St. Louis, and Julie Mennella, PhD, a biopsychologist at the Monell Center in Philadelphia, where the research was conducted, studied four groups of women ages 21 to 41: obese smokers, obese nonsmokers, smokers of normal weight and nonsmokers of normal weight. The women tasted several vanilla puddings containing varying amounts of fat and were asked to rate them for sweetness and creaminess, a measure of fat content.
“Compared with the other three groups, smokers who were obese perceived less creaminess and sweetness,” Pepino said. “They also derived less pleasure from tasting the puddings.”
The findings are published in the April issue of the journal Obesity.
Pepino cautioned that the study only identified associations between smoking and taste rather than definitive reasons why obese smokers were less likely to detect fat and sweetness. But the findings imply that the ability to perceive fat and sweetness — and to derive pleasure from food — is compromised in female smokers who are obese, which could contribute to the consumption of more calories.
“Obese people often crave high-fat foods,” she said. “Our findings suggest that having this intense craving but not perceiving fat and sweetness in food may lead these women to eat more. Since smoking and obesity are risk factors for cardiovascular and metabolic diseases, the additional burden of craving more fats and sugars, while not fully tasting them, could be detrimental to health.”
Interestingly, it was the combination of smoking and obesity that created something of a “double-whammy” because smokers who were not overweight could perceive fat and sweetness that was similar to women who did not smoke.
Previous studies have linked smoking to increased food cravings and greater consumption of fat, regardless of whether a smoker is obese. Studies also have found that smokers tend to have increased waist-to-hip ratios. That is, they tend to be shaped more like apples than pears, another risk factor for heart disease and metabolic problems.
The findings contribute to a growing body of knowledge that challenges the lingering perception that smoking helps a person maintain a healthy weight.
“Women are much more likely than men to take up smoking as an aid to weight control,” Pepino said. “But there is no good evidence showing that it helps maintain a healthy weight over the long term. And in the case of obese women who smoke, it appears the smoking may make things even worse than previously thought.”
(Source: news.wustl.edu)
Nicotine Withdrawal Weakens Brain Connections Tied to Self-Control Over Cigarette Cravings
People who try to quit smoking often say that kicking the habit makes the voice inside telling them to light up even louder, but why people succumb to those cravings so often has never been fully understood. Now, a new brain imaging study in this week’s JAMA Psychiatry from scientists in Penn Medicine and the National Institute on Drug Abuse (NIDA) Intramural Research Program shows how smokers suffering from nicotine withdrawal may have more trouble shifting from a key brain network—known as default mode, when people are in a so-called “introspective” or “self-referential” state— and into a control network, the so-called executive control network, that could help exert more conscious, self-control over cravings and to focus on quitting for good.
The findings help validate a neurobiological basis behind why so many people trying to quit end up relapsing—up to 80 percent, depending on the type of treatment—and may lead to new ways to identify smokers at high risk for relapse who need more intensive smoking cessation therapy.
The brain imaging study was led by researchers at University of Pennsylvania’s new Brain and Behavior Change Program, led by Caryn Lerman, PhD, who is also the deputy director of Penn’s Abramson Cancer Center, and Elliot Stein, PhD, and collaborators at NIDA. They found that smokers who abstained from cigarettes showed weakened interconnectivity between certain large-scale networks in their brains: the default mode network, the executive control network, and the salience network. They posit that this weakened connectivity reduces smokers’ ability to shift into or maintain greater influence from the executive control network, which may ultimately help maintain their quitting attempt.
“What we believe this means is that smokers who just quit have a more difficult time shifting gears from inward thoughts about how they feel to an outward focus on the tasks at hand,” said Lerman, who also serves as the Mary W. Calkins professor in the Department of Psychiatry. “It’s very important for people who are trying to quit to be able to maintain activity within the control network— to be able to shift from thinking about yourself and your inner state to focus on your more immediate goals and plan.”
Prior studies have looked at the effects of nicotine on brain interconnectivity in the resting state, that is, in the absence of any specific goal directed activity. This is the first study, however, to compare resting brain connectivity in an abstinent state and when people are smoking as usual, and then relate those changes to symptoms of craving and mental performance.
For the study, researchers conducted brain scans on 37 healthy smokers (those who smoke more than 10 cigarettes a day) ages 19 to 61 using functional magnetic resonance imaging (fMRI) in two different sessions: 24 hours after biochemically confirmed abstinence and after smoking as usual.
Imaging showed a significantly weaker connectivity between the salience network and default mode network during abstinence, compared with their sated state. Also, weakened connectivity during abstinence was linked with increases in smoking urges, negative mood, and withdrawal symptoms, suggesting that this weaker internetwork connectivity may make it more difficult for people to quit.
Establishing the strength of the connectivity between these large-scale brain networks will be important in predicting people’s ability to quit and stay quit, the authors write. Also, such connectivity could serve as a clinical biomarker to identify smokers who are most likely to respond to a particular treatment.
“Symptoms of withdrawal are related to changes in smokers’ brains, as they adjust to being off of nicotine, and this study validates those experiences as having a biological basis,” said Lerman. “The next step will be to identify in advance those smokers who will have more difficultly quitting and target more intensive treatments, based on brain activity and network connectivity.”
(Source: uphs.upenn.edu)
Want a good night’s sleep in the new year? Quit smoking
As if cancer, heart disease and other diseases were not enough motivation to make quitting smoking your New Year’s resolution, here’s another wake-up call: New research published in the January 2014 issue of The FASEB Journal suggests that smoking disrupts the circadian clock function in both the lungs and the brain. Translation: Smoking ruins productive sleep, leading to cognitive dysfunction, mood disorders, depression and anxiety.
"This study has found a common pathway whereby cigarette smoke impacts both pulmonary and neurophysiological function. Further, the results suggest the possible therapeutic value of targeting this pathway with compounds that could improve both lung and brain functions in smokers," said Irfan Rahman, Ph.D., a researcher involved in the work from the Department of Environmental Medicine at the University of Rochester Medical Center in Rochester, N.Y. "We envisage that our findings will be the basis for future developments in the treatment of those patients who are suffering with tobacco smoke-mediated injuries and diseases.
Rahman and colleagues found that tobacco smoke affects clock gene expression rhythms in the lung by producing parallel inflammation and depressed levels of brain locomotor activity. Short- and long- term smoking decreased a molecule known as SIRTUIN1 (SIRT1, an anti-aging molecule) and this reduction altered the level of the clock protein (BMAL1) in both lung and brain tissues in mice. A similar reduction was seen in lung tissue from human smokers and patients with chronic obstructive pulmonary disease (COPD). They made this discovery using two groups of mice which were placed in smoking chambers for short-term and long-term tobacco inhalation. One of the groups was exposed to clean air only and the other was exposed to different numbers of cigarettes during the day. Researchers monitored their daily activity patterns and found that these mice were considerably less active following smoke exposure.
Scientists then used mice deficient in SIRT1 and found that tobacco smoke caused a dramatic decline in activity but this effect was attenuated in mice that over expressed this protein or were treated with a small pharmacological activator of the anti-aging protein. Further results suggest that the clock protein, BMAL1, was regulated by SIRT1, and the decrease in SIRT1 damaged BMAL1, resulting in a disturbance in the sleep cycle/molecular clock in mice and human smokers. However, this defect was restored by a small molecule activator of SIRT1.
"If you only stick to one New Year’s resolution this year, make it quitting smoking," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. “Only Santa Claus has a list longer than that of the ailments caused or worsened by smoking. If you like having a good night’s sleep, then that’s just another reason to never smoke.”
Heavy smokers could be helped to kick the habit by having their brains zapped with electromagnetic pulses, new research suggests.
Repeated use of a high frequency magnet to stimulate the brain helps some smokers quit for up to six months after treatment, an Israeli study found.
The smokers had already tried a range of treatments, from patches to psychotherapy, raising hopes that brain stimulation could be an effective alternative for those who had so far failed to kick the habit.
Abraham Zangen of Ben Gurion University told the annual meeting of the Society for Neuroscience in San Diego, California, that more than half the smokers given high-frequency magnetic pulses quit.
More than a third were still abstaining six months on.
'Our research shows us that we may actually be able to undo some of the changes to the brain caused by chronic smoking,' said Dr Zangen.
'We know that many smokers want to quit or smoke less and this could help put a dent in the number one cause of preventable deaths.'
Dr Zangen’s team recruited 115 heavy smokers aged between 21 and 70 who were interested in quitting but who had failed in doing so on at least two previous attempts.
They then split the smokers into three groups, giving them either high frequency repeated Transcranial Magnetic Stimulation (rTMS), low frequency rTMS, or placebo treatment for 13 days.
Repeated high frequency Transcranial Magnetic Stimulation (rTMS) is a non-invasive technique that uses magnetic fields to stimulate large areas of neurons in the brain.
The researchers focused on stimulating the prefrontal cortex and the insula, which are the two brain areas associated with nicotine addiction.
Before each session, Dr Zangen got one of his PhD students to light a cigarette and take a drag in front of half the smokers in each group to awaken their cravings.
This was to make sure the smokers’ attention was directed at their addiction and not some other craving, said Dr Zangen.
The results were striking. Nearly half - 44 per cent - of the smokers who received the cue before their rTMS session gave up immediately after the 13-day course, with 33 per cent still of the smokes six months later.
Overall, participants who received high frequency rTMS smoked less and were more likely to quit, with success rates four times that of the low frequency group and more than six times greater than the placebo group.
Dr Zangen’s team are now planning a much larger trial involving smokers in several countries, which is set to start in the next few months.
He told The Guardian: ‘It’s quite easy to quit for a few days, or even for a few weeks, but if we can help people quit for more than three months, then they are actually quite unlikely to relapse later on.’
Dr Zanger did reveal that he has a financial interest in the company which provided the Transcranial Magnetic Stimulation equipment used in the study.
Smoking during pregnancy may increase risk of bipolar disorder in offspring
A study published today in the American Journal of Psychiatry suggests an association between smoking during pregnancy and increased risk for developing bipolar disorder (BD) in adult children. Researchers at the New York State Psychiatric Institute and the Department of Epidemiology at the Mailman School of Public Health at Columbia University, in collaboration with scientists at the Kaiser Permanente Division of Research in Oakland, California, evaluated offspring from a large cohort of pregnant women who participated in the Child Health and Development Study (CHDS) from 1959-1966. The study was based on 79 cases and 654 comparison subjects. Maternal smoking during pregnancy was associated with a twofold increased risk of BD in their offspring.
Smoking during pregnancy is known to contribute to significant problems in utero and following birth, including low birth weight and attentional difficulties. This is the first study to suggest an association between prenatal tobacco exposure and BD, a serious psychiatric illness marked by significant shifts in mood that alternate between periods of depression and mania. Symptoms typically become noticeable in the late teens or early adulthood.
"These findings underscore the value of ongoing public health education on the potentially debilitating, and largely preventable, consequences that smoking may have on children over time," said Alan Brown, MD, MPH, senior author and Professor of Clinical Psychiatry and Epidemiology at the New York State Psychiatric Institute, Columbia University and Mailman School of Public Health.
The authors wrote: “Much of the psychopathology associated with prenatal tobacco exposure clusters around the ‘externalizing’ spectrum, which includes attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), conduct disorder (CD), and substance abuse disorders. Although not diagnostically classified along the externalizing spectrum, BD shares a number of clinical characteristics with these disorders, including inattention, irritability, loss of self-control, and proclivity to drug/alcohol use.” In effect, children who were exposed to tobacco smoke in utero may exhibit some symptoms and behaviors that are found in BD.
A previous study by Dr. Brown and colleagues found that flu virus in pregnant mothers was associated with a fourfold increased risk that their child would develop BD.
(Image: istockphoto)
Research attributes high rates of smoking among mentally ill to addiction vulnerability
People with mental illness smoke at much higher rates than the overall population. But the popular belief that they are self-medicating is most likely wrong, according to researchers at the Indiana University School of Medicine. Instead, they report, research indicates that psychiatric disease makes the brain more susceptible to addiction.
As smoking rates in the general population have fallen below 25 percent, smoking among the mentally ill has remained pervasive, encompassing an estimated half of all cigarettes sold. Despite the well-known health dangers of tobacco consumption, smoking among the mentally ill has long been widely viewed as “self-medication,” reducing the incentive among health care professionals to encourage such patients to quit.
"This is really a devastating problem for people with mental illness because of the broad health consequences of nicotine addiction," said R. Andrew Chambers, M.D., associate professor of psychiatry at the IU School of Medicine. "Nicotine addiction is the number one cause of premature illness and death in the United States, and most of that morbidity and mortality is concentrated in people with mental illness."
In a report published recently in the journal Addiction Biology, the research team lead by Dr. Chambers reported the results of experiments using an established animal model of schizophrenia in which rats display a neuropsychiatric syndrome that closely resembles the disease.
Both the schizophrenia-model rats and normal rats were given access to intravenous self-administration of nicotine.
"The mentally ill rats acquired nicotine use faster and consumed more nicotine," Dr. Chambers said. "Then when we cut them off from access to nicotine, they worked much harder to restore access to nicotine than did the normal ‘control’ rats."
In additional testing, the researchers found that administration of nicotine provided equal, but minimal, cognitive benefits to both groups of rats when performing a memory test. When the nicotine was withdrawn, however, both groups of rats were more cognitively impaired, so that any cognitive benefits to nicotine administration were “paid for” by cognitive impairments later.
“These results strongly suggest that what has changed in mental illness to cause smoking at such high rates results in a co-morbid addiction to which the mentally ill are highly biologically vulnerable. The evidence suggests that the vulnerability is an involuntary biological result of the way the brain is designed and how it develops after birth, rather than it being about a rational choice to use nicotine as a medicine,” Dr. Chambers said.
The data, he said, point to neuro-developmental mechanisms that increase the risk of addiction. Better understanding of those mechanisms could lead to better prevention and treatment strategies, especially among mentally ill smokers, Dr. Chambers said.
A video interview of Dr. Chambers discussing his research is available here.
(Source: news.medicine.iu.edu)
Hypertensive smoking women have an exceptionally high risk of a fatal brain bleeding
Subarachnoid haemorrhage (SAH) is one of the most devastating cerebrovascular catastrophes causing death in 40 to 50% of the cases. The most common cause of SAH is a rupture of an intracranial aneurysm. If the aneurysm is found, it can be treated before the possible rupture. However, some intracranial aneurysms will never rupture – the problem is that the doctors don’t know which aneurysms will and which will not. So, they don’t know which patients should be treated and who can safely be left untreated.
(Image: This picture shows: A middle cerebral artery bifurcation aneurysm. Credit: Miikka Korja)
A long-term, population-based Finnish study on SAH, which is based on the FINRISK health examination surveys, and published in PLOS ONE on 9th September, shows that the risk of SAH depends strongly on the combination of certain risk factors. The SAH incidence was shown to vary from 8 up to 171 per 100 000 person-years, depending on whether people had multiple risk factors for SAH – such as smoking, hypertension and female sex – or not.
Such an extreme risk factor -dependent variation in the incidence of any cardiovascular disease is exceptional, and may have significant clinical implications, says one of the main authors, Associate Professor Miikka Korja from the Helsinki University Central Hospital and Australian School of Advanced Medicine.
If smoking women with high systolic blood pressure values have 20 times higher rate of these brain bleeds than never-smoking men with low blood pressure values, it may very well be that these women diagnosed with unruptured intracranial aneurysms should be treated. On the other hand, never-smoking men with low blood pressure values and intracranial aneurysms may not need to be treated at all.
In this largest SAH risk factor study ever, the study group also identified three new risk factors for SAH: previous myocardial infarction, history of stroke in mother, and elevated cholesterol levels in men. The results revise the understanding of the epidemiology of SAH and indicate that the risk factors for SAH appear to be similar to those for other cardiovascular diseases.
We have previously shown that lifestyle risk factors affect significantly the life expectancy of SAH survivors, and now we have shown that the same risk factors also affect dramatically the risk of SAH itself. Thus, it appears quite clear that especially smoking cessation and hypertension treatment are important in preventing SAH and increasing life expectancy after SAH, clarifies one of the study group members, Academy Professor Jaakko Kaprio, from the University of Helsinki and National Institute for Health and Welfare, referring to their previous publication on cause-specific mortality on SAH survivors (Korja et al., Neurology, 2013).
The study group members have previously published also the largest twin study to date, confirming that heritability for SAH is very low (Korja et al., Stroke, 2010), and the first study on the incidence of SAH in type 1 diabetes, showing that the rate of non-aneurysmal SAHs in type 1 diabetes is unusually high (Korja et al., Diabetes Care, 2013).
Many of the previous studies on the epidemiology of SAH have relied on retrospective and single-center databases, which are unfortunately not very reliable data sources. Due to the unique health care system and common academic interest among doctors in Nordic countries, it has been possible to conduct high-quality and unbiased studies on SAH. We hope that our studies truly help doctors and patients, and are not only of interest in coffee tables on university campuses, says neurosurgeon Korja, and rushes to continue his working day in the operation room in Macquarie University Hospital, Sydney, which is one of his current appointments.
(Source: eurekalert.org)