Category: Eating Disorders

Scientists at The Children's Hospital of Philadelphia have identified both common and rare gene variants associated with the eating disorder anorexia nervosa. In the largest genetic study of this psychiatric disorder, the researchers found intriguing clues to genes they are subjecting to further investigation, including genes active in neuronal signaling and in shaping interconnections among brain cells.

Anorexia nervosa (AN) affects an estimated 9 in 1000 women in the United States. Patients have food refusal, weight loss, an irrational fear of weight gain even when emaciated, and distorted self-image of body weight and shape.

Women are affected 10 times more frequently than men, with the disorder nearly always beginning during adolescence. AN has the highest mortality rate of all psychiatric disorders, and successful treatment is challenging.

Twin studies and other family studies have suggested that AN is strongly heritable. "However, despite various genetic studies that identified a handful of candidate genes associated with AN, the genetic architecture underlying susceptibility to AN has been largely unknown," said study leader Hakon Hakonarson, M.D., Ph.D., director of the Center for Applied Genomics at The Children's Hospital of Philadelphia. The research appeared online in Molecular Psychiatry on Nov. 16.

"This is the first genome-wide association study on a large anorexia cohort, as well as the first study of copy number variations in the disorder," said Hakonarson. Genome-wide association studies (GWAS) search for single-nucleotide polymorphisms, or SNPs — common gene variants that typically act as pointers to a gene region with a small effect on raising disease risk. The study team also performed a parallel search for copy number variations (CNVs), rarer variants that usually have a stronger impact on disease risk.

The sample size was the largest used in an AN gene study — DNA came from 1,003 AN patients, all but 24 of them female, from various sources, having an average age of 27 years. For comparison, there was a control group of 3,733 pediatric subjects (average age of 13), drawn from the Children's Hospital pediatric network.

"We confirmed results of previous studies of anorexia nervosa: SNPs in the gene OPRD1 and near the gene HTR1D confer risk for the disease," said Hakonarson. "We did not detect other obvious candidate genes, but we did generate a list of other genes that we are analyzing in follow-up studies." One SNP is between the CHD10 and CHD9 genes, a region that Hakonarson associated with autism spectrum disorders in 2009. Called cadherin genes, CHD10 and CHD9 code for neuronal cell-adhesion molecules — proteins that influence how neurons communicate with each other in the brain.

The current anorexia study also investigated CNVs — deletions or duplications of DNA sequences. Previous research by Hakonarson and others has shown that CNVs play a significant role in other neuropsychiatric disorders, such as schizophrenia, bipolar disorder and autism.

The current study suggests that CNVs may play a less important role in anorexia than they do in schizophrenia and autism. Nonetheless, the researchers identified several rare CNVs that occurred only in AN cases, including a deletion of DNA on a region of chromosome 13.

"Our study suggests that both common SNPs and rare CNVs contribute to the pathogenesis of anorexia nervosa," said Hakonarson. "The gene variants we discovered are worthy of further analysis in independent cohorts. However, the relatively modest number of anorexia cases explained by these results we found suggests that many other candidate genes remain unknown. Future studies will require much larger sample sizes to detect additional gene variants involved in this complex disorder."

Support for this research came from an Institute Development Award from The Children's Hospital of Philadelphia, as well as from the Price Foundation, the Klarman Family Foundation, and the Scripps Translational Science Institute of La Jolla, Calif. Hakonarson's co-authors were from the University of Pennsylvania, the Scripps Translational Science Institute, the Scripps Research Institute, the University of California, San Diego, and the Price Foundation Collaborative Group.

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Journal Reference:

1. K Wang, H Zhang, C S Bloss, V Duvvuri, W Kaye, N J Schork, W Berrettini, H Hakonarson. A genome-wide association study on common SNPs and rare CNVs in anorexia nervosa. Molecular Psychiatry, 2010; DOI: 10.1038/mp.2010.107

Dealing with extended family, increased commitments and even celebratory occasions can cause a compulsive overeater to gain too much weight during the holiday season.

"Many of us deal with depression, disappointment, loneliness and unfulfilled expectations during the holiday season," said Stefanie C. Barthmare, a psychotherapist with the Methodist Weight Management Center in Houston. "When our ideal holiday expectations are not met, we feel bad. That's when many of us resort to eating more food, more often, to keep the deeper stuff at bay."

Compulsive overeaters use food to deal with stress. Daily anxiety, challenges and frustrations are often softened by things like cookies, chocolate and nuts, all common holiday gifts. This problem, often beginning in childhood, may continue into adulthood and appear to go unnoticed because it's just a normal part of the holiday season. Unfortunately, dangerous weight gain may be the result. Gaining the weight then brings on feelings of guilt and shame and, eventually, more bingeing. Learning to deal with and manage these difficult feelings requires patience and persistence, especially when food is used as a way to cope.

"Quite frequently, even the feeling of fullness does not prohibit one from eating vast amounts of food," Barthmare said. "The food might initially help ease anxiety or difficult feelings, however, then it becomes a way of always managing feelings and then causes excessive weight gain."

Barthmare says because the compulsive eating behavior gets established a little at a time, the consequences are gradual, thus the motivation to change is lower. The time to begin changing the pattern is now because most of us gain anywhere from 5 to 15 pounds during the holiday season.

"Changing this destructive pattern requires support from those around you, and an awareness of what is going on with your body," Barthmare said. "Structured meal times, menus planned with a full-range of a person's schedule, needs and lifestyle all need to be taken care of for you to successfully breakthrough and stop compulsive eating."

A new study by University of North Carolina at Chapel Hill and Norwegian researchers has found that women with anorexia nervosa are much more likely to have both unplanned pregnancies and induced abortions than women who don't have the serious eating disorder.

These results may be driven by a mistaken belief among women with anorexia that they can't get pregnant because they are either not having menstrual periods at all or are having irregular periods, said Cynthia M. Bulik, PhD, the study's lead author and director of the UNC Eating Disorders Program.

"Anorexia is not a good contraceptive," Bulik said. "Just because you're not menstruating, or because you're menstruating irregularly, doesn't mean you're not at risk for becoming pregnant."

Physicians and other health care providers need to be aware of this as well, Bulik said. Doctors who treat women and adolescent girls, in particular, "need to make sure that they have the conversation about sexuality and contraception as clearly with patients with anorexia as they do with all other girls and women." In addition, providers who take care of pregnant women need to know when their patients have an eating disorder in order to provide appropriate care. Screening for eating disorders during prenatal visits would be an excellent first step, Bulik said.

In the study, published in the November 2010 issue of the journal Obstetrics & Gynecology, Bulik and study co-authors analyzed data collected from 62,060 women as part of the Norwegian Mother and Child Cohort Study. There were 62 women in this sample who reported having anorexia nervosa.

The differences between women with anorexia and women with no eating disorder were striking. The average age of the mothers at delivery was 26.2 years in women with anorexia, compared with 29.9 years in the referent group of women without eating disorders. Fifty percent of women with anorexia reported unplanned pregnancies, compared with 18.9 percent, while 24.2 percent of women with anorexia reported having induced abortions in the past, compared to 14.6 percent.

Co-authors of the study from UNC are Elizabeth R. Hoffman, an MD, PhD student, and biostatistician Ann Von Holle, MS. Co-authors from the Norwegian Institute of Public Health are Leila Torgersen, PhD, Camilla Stoltenberg, MD, drMed; and Ted Reichborn-Kjennerud, MD, drMed.

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Journal Reference:

1. Cynthia M. Bulik, Elizabeth R. Hoffman, Ann Von Holle, Leila Torgersen, Camilla Stoltenberg, Ted Reichborn-Kjennerud. Unplanned Pregnancy in Women With Anorexia Nervosa. Obstetrics & Gynecology, 2010; 116 (5): 1136 DOI: 10.1097/AOG.0b013e3181f7efdc

 Over the last few decades, the dramatic rise in pediatric obesity rates has emerged as a public health threat requiring urgent attention. The responsibility of identifying and treating eating and weight-related problems early in children and adolescents falls to health care providers and other professionals who work with the child, according to Professor Denise Wilfley and colleagues from the Department of Psychiatry at Washington University School of Medicine in the US. Furthermore, the key to successful treatment is a team effort involving providers and parents.

Wilfley's review of the causes, consequences, and early intervention of eating and weight-related problems in young people is published online in Springer's Journal of Clinical Psychology in Medical Settings. Wilfley and colleagues' paper highlights the important roles of mental health care providers in this effort.

The review examines the scope of the obesity problem, highlighting the dramatic increases in childhood obesity. The authors focus on the causes of eating- and weight-related problems in children and adolescents, attending to the complex interactions between environmental and biological factors, and dysregulated eating behaviors known as appetitive traits. In particular, the authors discuss binge eating and loss-of-control eating; satiety responsiveness or eating in the absence of hunger; motivation to eat; and impulsivity. For each trait, the authors identify screening approaches, as well as targeted intervention strategies that can be implemented by providers.

The authors find that, by far, the most effective strategies to combat childhood obesity are lifestyle behavioral interventions, and those involving the whole family in particular. Family-based behavioral interventions are considered the first-line of treatment for pediatric overweight, and weight maintenance interventions aimed at the socio-environmental context are indicated as well. These interventions promote small, successive changes in children's dietary and physical activity behaviors through the use of behavior change strategies and familial support.

The authors conclude: "Not only are there more obese children now than in the past, but the severity of overweight among these children is also much greater. The dramatic increase in pediatric obesity rates has created a mounting need for clinicians, psychologists, and other mental health care providers to play a significant role in the assessment and treatment of youth with eating- and weight-related problems."

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Journal Reference:

1. Denise E. Wilfley, Anna Vannucci, Emily K. White. Early Intervention of Eating- and Weight-Related Problems. Journal of Clinical Psychology in Medical Settings, 2010; DOI: 10.1007/s10880-010-9209-0

 The eating disorder anorexia nervosa causes potentially serious eye damage, suggests a small study published online in the British Journal of Ophthalmology.

In developed countries, anorexia nervosa affects up to 3% of affluent women. Although the condition also increasingly affects men, around 10 women will be affected for every one man.

Anorexia nervosa is the third most common chronic disease among teenage women, up to one in 10 of whom will die from it.

Researchers analysed the thickness of the macula and its electrical activity in both eyes of 13 women with anorexia nervosa and in 20 healthy women of the same age.

The average age of the women was 28. Those with anorexia had had their condition for an average of 10 years.

The macula lies near the centre of the retina at the back of the eye and is responsible for fine detailed central vision and the processing of light.

The tests to determine how well the eyes picked up fine detail, central vision, and colour showed that there were no obvious visual problems and that the eyes were working normally in both sets of women.

But the analysis showed that the macula and the nerve layers feeding it (retinal nerve fibre layer) were significantly thinner in the eyes of the women with anorexia nervosa

There was also significantly less firing of the neurotransmitter dopamine (electrical activity) in the eyes of the women with anorexia nervosa. Dopamine neurotransmission is a key element of the brain's ability to process visual images.

There even seemed to be differences between women with different patterns of anorexia.

The fovea — a small pit more or less at the centre of the macula that is rich in light sensitive cone cells (photoreceptors) — was thinner in those women who binged and purged than in those who simply severely restricted their calorie intake.

The authors conclude that it is not yet clear whether macular thinning and decreased neurotransmitter activity are the initial stages of progressive blindness or whether these signs will revert back to normal once normal eating patterns are resumed.

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Journal Reference:

1. Marilita M Moschos, Fragiskos Gonidakis, Eleftheria Varsou, Ioannis Markopoulos, Alexandros Rouvas, Ioannis Ladas, George N Papadimitriou. Anatomical and functional impairment of the retina and optic nerve in patients with anorexia nervosa without vision loss. British Journal of Ophthalmology, 2010; DOI: 10.1136/bjo.2009.177899

An alarming number of adolescents already battling eating disorders are also intentionally cutting themselves, and health-care providers may be failing to diagnose many instances of such self-injury, according to a new study from Stanford University School of Medicine and Lucile Packard Children's Hospital.

The researchers found that 40.8 percent of patients with eating disorders in their study had documented incidents of intentionally harming themselves, most often by cutting and burning. What's more, the study suggests that inadequate clinical screening might mean the count should be much higher.

"These are very high numbers, but they're still conservative estimates," said the study's lead author, Rebecka Peebles, MD, who was an instructor in pediatrics at Stanford when the research was conducted and is joining the faculty at Children's Hospital of Philadelphia.

Peebles noted that clinicians aren't routinely asking about this activity. "We ask 97 percent of children 12 years and up if they smoke cigarettes; we need to get that good with screening for self-injurious behavior," she said.

The study is to be published online Oct. 8 in the Journal of Adolescent Health. Its senior author is James Lock, MD, PhD, professor of psychiatry and behavioral sciences and of pediatrics. He is also psychiatric director of the Comprehensive Eating Disorders Program at Packard Children's Hospital.

To conduct the study, the researchers examined the intake evaluation records of 1,432 patients, ages 10-21, who were admitted to the hospital's eating disorders program from January 1997 through April 2008. Just over 90 percent of all the patients were female, three-quarters of them white, with a mean age of 15. Among the 40.8 percent identified to be physically harming themselves, the mean age was 16. Many of these patients had a history of binging and purging, and 85.2 percent of the self-injurers were cutting themselves.

The researchers also discovered that slightly fewer than half the charts showed that health-care providers had asked patients if they intentionally injured themselves. If patients aren't asked, they are unlikely to volunteer such information, said Peebles.

Those who were questioned tended to fit previously published profiles of a self-injurer: older, white, female, suffering from bulimia nervosa, or with a history of substance abuse. "The question is, 'Are we missing other kids who are not meeting this profile?'" Peebles said. "This is part of why we wanted to look at this. If you see an innocent-looking 12-year-old boy, you don't even think of asking about self-injurious behavior. We need to get much better about universal screening."

Peebles noted that the profile itself might be flawed. If health-care workers only ask a certain type of patient about a behavior, the profile that emerges will necessarily reflect that bias, she said.

The study did not examine the reasons behind such acts but Peebles said her clinical experience suggested patients "are trying to feel pain."

"Patients describe a feeling of release that comes when they cut or burn themselves," she said. "They'll cut with a razor or a scissor blade. Sometimes we've even had kids who will take the tip of a paper clip and gouge holes. To burn themselves, they'll heat up a metal object and press it to their skin, or they'll use cigarettes."

Physicians and other health-care providers at Packard's Comprehensive Eating Disorders Program now question all new patients about self-injurious behavior. Studies have shown that between 13 and 40 percent of all adolescents engage in some form of self-injury, which is also associated with a higher risk of suicide.

"In clinical practice, kids are fairly open when you engage with them," Peebles said. "They'll come in wearing long sleeves, or hiding the marks on their inner thighs. But then when you ask them, they are usually willing to discuss the behavior."

The study's other author is Jenny Wilson, MD, who was a resident in pediatrics when the study was conducted.

The study was funded in part by the Stanford Child Health Research Program.

Family-based therapy, in which parents of adolescents with anorexia nervosa are enlisted to interrupt their children's disordered behaviors, is twice as effective as individual psychotherapy at producing full remission of the disease, new research from the Stanford University School of Medicine, Lucile Packard Children's Hospital and the University of Chicago shows. The study is the first head-to-head comparison of these two common treatment approaches for adolescents suffering from the eating disorder.

"This research was desperately needed," said James Lock, MD, PhD, one of the study's two lead authors and a professor of psychiatry and behavioral sciences at Stanford. "Anorexia nervosa is a life-threatening illness, and it's really remarkable how little information we have about how to treat it. There are serious cons to not knowing what to do."

The research will be published Oct. 4 in the Archives of General Psychiatry.

Patients with anorexia nervosa inaccurately believe they are fat, and use food restriction and exercise to maintain dangerously low body weights. The disease, which affects about 0.5 to 0.7 percent of adolescent girls, kills about one in every 10 patients.

Lock's team at Stanford collaborated with researchers at the University of Chicago to test family-based therapy against individual psychotherapy therapy in 121 male and female anorexia patients aged 12 to 18. In family-based therapy, the clinician trains the patient's parents to help ensure that their child eats enough and does not overexercise. Individual psychotherapy, in contrast, focuses on resolving the patient's underlying anxiety and emotional problems, with only minimal involvement from the family. In order to control for differences between clinicians, all therapists in the study had patients in both treatment groups.

The researchers evaluated each patient's condition at the start and end of the one-year treatment period, and then again six and 12 months after treatment ended. Patients were considered in full remission if they reached 95 percent of normal body weight and had a normal score on a standardized psychiatric assessment of attitudes about eating. At the end of the study, 49.3 percent of family-based therapy patients were in full remission, whereas 23.2 percent of individual psychotherapy patients were in full remission. The two treatments were equally effective in helping patients achieve partial remission, characterized by reaching a body weight of 85 percent of normal.

"Although both treatments were helpful to a proportion of patients, this study strongly suggests that as first-line treatment, in general, family-based interventions are superior," said Lock, who is also psychiatric director of the Comprehensive Eating Disorders Program at Packard Children's.

"For the first time, we can confidently present parents with a treatment we consider the gold standard for this patient population," added Daniel Le Grange, PhD, the other lead author of the study and a professor of psychiatry and behavioral neuroscience at the University of Chicago.

Lock noted, however, that individual psychotherapy works better in some cases, and that he and his colleagues at Packard Children's routinely offer both types of therapy. The scientists are now further analyzing the data to see if they can figure out how to identify which types of patients should be directed toward each therapy.

Although the study did not determine exactly why family-based therapy was more effective, Lock speculated that the treatment might have worked better because "it's a more direct approach."

"Restrictive eating and overexercise contribute to the maintenance of anorexic thinking," he said, noting prior research has shown that even healthy individuals develop anxious, obsessive, ritualistic thinking patterns about food when they are starving. "If you disrupt the maintaining behaviors of anorexia and get the patients eating, you disrupt that sequence of thinking. The traction of the thinking itself becomes less."

Prior to the study, Lock said, the investigators had speculated that individual psychotherapy might have better long-term results because it attempts to resolve the psychological problems that may underpin the disorder. "The interesting thing to me is that relapse was a lot greater in the individual psychotherapy group," he said. "It suggests that the behavioral components of anorexia nervosa are very powerful at maintaining the disease."

Lock also noted that family-based therapy obtained better long-term results than previous trials in which patients have been hospitalized for anorexia nervosa. Although the earlier trials showed that hospitalized patients gained weight, they often lost much of the weight soon after they returned home.

"In contrast, patients receiving family-based therapy had to learn to eat enough in the context of their real life," he said. "They didn't face a step off the cliff into the real world."

Lock hopes the study's results will encourage those who treat adolescent anorexia nervosa to learn to use family-based therapy.

"I would like clinicians to see that parents can be helpful," he said. "The model of putting kids in the hospital, which excludes parents, or of professionals expecting young adolescents to manage their own eating without their parents' help when they're immersed in anorexic thinking, really should be reconsidered."

Future research will be needed to test whether teens treated with family-based therapy continue to do well after they move away from home, Lock noted.

Lock's collaborators at Stanford were Stewart Agras, MD, professor emeritus of psychiatry and behavioral sciences; senior scientific programmer Susan Bryson; and Booil Jo, PhD, assistant professor of psychiatry and behavioral sciences.

The researchers have written two books on family-based therapy. With Le Grange, Lock wrote a book for parents called Help Your Teenager Beat an Eating Disorder (Guilford Publications, 2005). Lock, Le Grange and Agras are co-authors of a book for clinicians called Treatment Manual for Anorexia Nervosa: A Family-Based Approach (Guilford Publications, 2002).

The research was funded by grants from the National Institutes of Health.

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Journal Reference:

1. James Lock, MD, PhD; Daniel Le Grange, PhD; W. Stewart Agras, MD; Ann Moye, PhD; Susan W. Bryson, MA, MS; Booil Jo, PhD. Randomized clinical trial comparing family based treatment to adolescent focused individual therapy for adolescents with anorexia nervosa. Archives of General Psychiatry, 010;67[10]:1025-1032 DOI: 10.1001/archgenpsychiatry.2010.128

New research provides evidence of the vicious cycle created when an obese individual overeats to compensate for reduced pleasure from food.

Obese individuals have fewer pleasure receptors and overeat to compensate, according to a study by University of Texas at Austin senior research fellow and Oregon Research Institute senior scientist Eric Stice and his colleagues published in The Journal of Neuroscience.

Stice shows evidence this overeating may further weaken the responsiveness of the pleasure receptors ("hypofunctioning reward circuitry"), further diminishing the rewards gained from overeating.

Food intake is associated with dopamine release. The degree of pleasure derived from eating correlates with the amount of dopamine released. Evidence shows obese individuals have fewer dopamine (D2) receptors in the brain relative to lean individuals and suggests obese individuals overeat to compensate for this reward deficit.

People with fewer of the dopamine receptors need to take in more of a rewarding substance — such as food or drugs — to get an effect other people get with less.

"Although recent findings suggested that obese individuals may experience less pleasure when eating, and therefore eat more to compensate, this is the first prospective evidence to show that the overeating itself further blunts the award circuitry," says Stice, a senior scientist at Oregon Research Institute, a non-profit, independent behavioral research center. "The weakened responsivity of the reward circuitry increases the risk for future weight gain in a feed-forward manner. This may explain why obesity typically shows a chronic course and is resistant to treatment."

Using Functional Magnetic Resonance Imaging (fMRI), Stice's team measured the extent to which a certain area of the brain (the dorsal striatum) was activated in response to the individual's consumption of a taste of chocolate milkshake (versus a tasteless solution). Researchers tracked participants' changes in body mass index over six months.

Results indicated those participants who gained weight showed significantly less activation in response to the milkshake intake at six-month follow-up relative to their baseline scan and relative to women who did not gain weight.

"This is a novel contribution to the literature because, to our knowledge, this is the first prospective fMRI study to investigate change in striatal response to food consumption as a function of weight change," said Stice. "These results will be important when developing programs to prevent and treat obesity."

The research was conducted at the The University of Oregon brain imaging center.

Stice has been studying eating disorders and obesity for 20 years. This research has produced several prevention programs that reliably reduce risk for onset of eating disorders and obesity.

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Journal Reference:

1. E. Stice, S. Yokum, K. Blum, C. Bohon. Weight Gain Is Associated with Reduced Striatal Response to Palatable Food. Journal of Neuroscience, 2010; 30 (39): 13105 DOI: 10.1523/JNEUROSCI.2105-10.2010

— When it comes to self-control, consumers in the United States are in trouble. But a new study in the Journal of Consumer Research says there's hope; we just need a little help to see self-regulation as fun.

"Self-control failures depend on whether people see activities involving self-control (e.g., eating in moderate quantities) as an obligation to work or an opportunity to have fun," write authors Juliano Laran (University of Miami) and Chris Janiszewski (University of Florida, Gainesville).

According to the authors, approximately one in five U.S. citizens over the age of 12 admits to binge drinking at least once per month, and nearly 10 million people suffer from clinical eating disorders. These epidemics make it critical to examine what can be done to encourage people to regulate consumption.

In one study, the researchers asked participants to hold pieces of candy between their fingers, and put it in their mouths and then take it out. "The goal of this task was to let people perform tasks with the candy but not be able to actually eat the candy," the authors explain.

Once the participants completed the initial tasks they moved on to taking unrelated surveys. But the candy was left on their desks without instruction as to whether they could eat it or not. The researchers measured how much candy the participants consumed and measured how much self-control the participants usually exerted. "We found that participants who are usually high in self-control perceived the initial candy task — which involved touching, but not eating Skittles and M&Ms — as an opportunity to have fun (they were playing with candy)," the authors write. "Participants who are usually low in self-control, however, perceived the initial candy task as an obligation to work."

Both low and high self-control individuals showed self-control success in a similar study where the word "fun" was included in the instructions for the initial task. "These results show that low self-control people can be made to act like high self-control people and show regulatory success if tasks that involve exerting self-control are framed in a way that people will perceive it as fun and not work," the authors conclude.

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Journal Reference:

1. Juliano Laran and Chris Janiszewski. Work or Fun? How Task Construal and Completion Influence Regulatory Behavior. Journal of Consumer Research, April 2011 

Ezlopitant, a compound known to suppress craving for alcohol in humans, was shown to decrease consumption of sweetened water by rodents in a study by researchers at the Ernest Gallo Clinic and Research Center, which is affiliated with the University of California, San Francisco.

"This finding suggests a possible link between the neurochemical pathways for addiction and compulsive eating," says principal investigator Selena Bartlett, PhD, Director of the Pre-Clinical Development Group at the Gallo Center.

The study will be published online in PLoS ONE on September 1, 2010.

Ezlopitant is an NK1 receptor-antagonist, a class of drugs that blocks the action of substance P, a neurotransmitter that is believed to play a role in the reward system. The reward system is a complex of brain structures that, among other things, governs craving for, and addiction to, alcohol and drugs.

"Substance P is released in your brain in response to certain stimuli, and needs to bind with receptors on neurons in order to have an effect," Bartlett explains. "The NK1 receptor is where it binds, and ezlopitant prevents that binding."

In the study, rats given ezlopitant showed significantly decreased motivation to consume water sweetened with sugar, water sweetened with saccharin, and an alcohol solution.

Bartlett believes one possible explanation is that the NK1 receptor is part of the same reward system that links compulsive craving for sweets with craving for drugs and alcohol.

"In other studies, NK1-receptor antagonists have been shown to decrease craving for alcohol in humans with alcohol-use disorder," she says. "In our study, the decrease in the rats' consumption of sweetened water was, in fact, even greater than their decrease in alcohol consumption. For the first time, we've shown that this receptor might be a target for compulsive eating. We're looking at a potentially promising new approach to addressing pathological food addiction.

Bartlett notes that her laboratory is focused on the development of medications for human use, so, "naturally," she says, "we'd like to see this experiment replicated in humans as soon as possible."

Co-authors of the study were Pia Steensland of the Karolinksa Institute, Stockholm, Sweden, and Jeffrey A. Simms, Carsten K. Nielsen, Joan Holgate, and Jade J. Bito-Onon of the Preclinical Development Group at the Gallo Center.

The study was supported by funds from the State of California for medical research on alcohol and substance abuse through UCSF, and from the US Department of Defense.

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Journal Reference:

1. Pia Steensland, Jeffrey A. Simms, Carsten K. Nielsen, Joan Holgate, Jade J. Bito-Onon, Selena E. Bartlett. The Neurokinin 1 Receptor Antagonist, Ezlopitant, Reduces Appetitive Responding for Sucrose and Ethanol. PLoS ONE, 2010; DOI: 10.1371/journal.pone.0012527