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Stress found to influence brain networks and reduce self-control


After a stressful day of work, good intentions concerning dieting and exercise can quickly go out the window. Now, a new study from researchers at the University of Zürich in Switzerland has demonstrated how stress can influence regions of the brain involved with self-control.

Their findings, published in Neuron, shed further light on how stress and self-control interact in the human brain, with the effects of stress operating through multiple neural pathways, according to lead author Silvia Maier, a PhD candidate in neuroeconomics.

"Self-control abilities are sensitive to perturbations at several points within this network," she explains, "and optimal self-control requires a precise balance of input from multiple brain regions rather than a simple on/off switch."

Important decisions have to be made in stressful conditions on a daily basis. Sometimes, stressful circumstances can compromise an individual's ability to exhibit self-control, in turn affecting the decision-making process.

Despite how frequently such decisions are made, however, the manner in which stress affects processes within the brain is not fully understood.

To investigate, the researchers assessed a number of individuals who were attempting to maintain a healthy lifestyle in terms of diet and exercise and looked at how stress affected choices they made about food.

Stressed participants more likely to choose tasty, unhealthy food over healthy options.

A total of 29 participants were observed and evaluated by an experimenter while one of their hands was immersed in cold water for 3 minutes in order to induce a moderate level of stress.

Following this treatment, the participants had to choose repeatedly between two food options presented on a screen - a tasty but unhealthy option and a healthy but less tasty option - for them to eat following the experiment. Maier told Medical News Today that the food options on offer were tailored to each participant.

"As what each person will find tasty is very unique, we try to cater to everyone's taste by asking for participant's taste ratings on a large set of foods beforehand," she explained. "We then customized a set of foods for each participant in the experiment that covered a wide spectrum of taste and health trade-offs."

To prevent preferences unrelated to taste influencing the decisions of the participants, Maier told MNT that they also excluded any individuals with food intolerances or allergies from participation in the study.

These participants' decisions were then compared with those made by a further 22 participants who did not undergo the stress-inducing treatment. In addition to assessing the choice made by the participants, the researchers also conducted fMRI (functional magnetic resonance imaging) scans to see how their brains were affected.

The researchers found that the participants subjected to stress-inducing treatment were more likely to value a food's taste over its healthfulness when choosing what to eat compared with participants who were not stressed. This finding indicated that stress increased the influence of immediately rewarding attributes on choice and reduced self-control.

In the brains of the participants subjected to stress, changes were observed in various regions of the brain. The researchers noted increased connectivity between the ventromedial prefrontal cortex (vmPFC) region and the amygdala and striatal regions - regions associated with perceiving tastiness.

Reduced connectivity was also observed between the vmPFC region and the dorsolateral prefrontal cortex regions - regions associated with successfully exhibiting self-control. However, only some of these connectivity changes were associated with cortisol, a hormone associated with stress.

Senior author Todd Hare, an assistant professor in neuroeconomics, states that these findings indicate self-control can be inhibited by even moderate levels of stress, which is important as moderate levels of stress affect a larger portion of the population than extreme stress events. He adds:

"One interesting avenue for future research will be to determine whether some of the factors shown to protect against structural brain changes following severe stress - such as exercise and social support - can also buffer the effects of moderate stress on decision making."

Recently, MNT reported on a study suggesting that alterations to gut bacteria induced by stress in early life could contribute to the development of anxiety and depression in adulthood.

Source: Medical News Daily 

Antipsychotic use rising among teens and young adults


A growing number of teens and young adults are being prescribed antipsychotics, a new study suggests.

In particular, it appears they’re being used to treat attention deficit and hyperactivity disorder (ADHD) – a condition for which the powerful drugs are not approved. The percentage of teens using antipsychotics rose from 1.10 percent in 2006 to 1.19 percent in 2010. Use among young adults ages 19 to 24 rose from 0.69 percent to 0.84 percent, the study found.

With roughly 74 million children under 18 in the U.S., these small percentages add up to large numbers of medicated kids. “Great caution should be exercised in the use of antipsychotics, especially for young children,” said lead study author Dr. Mark Olfson, a research psychiatrist at Columbia University in New York. Olfson and colleagues analyzed prescription data from 2006, 2008, and 2010 as well as records from 2009 combining pharmacy and medical claims information.

The records covered prescriptions filled at approximately 60 percent of all retail pharmacies in the U.S.

Overall in 2010, approximately 270,000 antipsychotic prescriptions were dispensed to younger children, 2.14 million to older children, 2.80 million to adolescents, and 1.83 million to young adults, the authors write. Antipsychotic drugs include Abilify (aripiprazole), Risperdal (risperidone), Seroquel (quetiapine), Zyprexa (olanzapine) and others.

For younger children, antipsychotic use declined from 2006 to 2010, the researchers report in JAMA Psychiatry. Prescriptions fell from 0.14 percent to 0.11 percent for kids aged one to six, and from 0.85 percent to 0.80 percent for children aged seven to 12. This is most likely due to increased efforts to curb antipsychotic use among younger kids over concerns about side effects such as weight gain, high cholesterol and uncertainty about the long-term effects of the drugs on the developing nervous system, Olfson said by email.

Among children 18 and under, the most common reason for antipsychotics was ADHD, the study found. This diagnosis accounted for about 53 percent of prescriptions for younger children, 60 percent for older kids, and 35 percent for teens. “This is concerning because evidence of antipsychotics’ efficacy for treating a number of behavioral health disorders is lacking,” said Meredith Matone, a research scientist with PolicyLab at the Children’s Hospital of Philadelphia.

Antipsychotics are approved in the U.S. for treatment of psychotic conditions including bipolar disorder and schizophrenia, as well as for easing aggression among cognitively impaired youth, Matone, who wasn’t involved in the study, said by email. “Increasingly, many youth are receiving these medications to treat behavior problems in the absence of a more severe psychiatric illness,” she said. Part of this may be due to who is prescribing the drugs, according to an editorial by Dr. Christoph Correll, a psychiatry researcher at the Zucker Hillside Hospital in Glen Oaks, New York and the North Shore-Long Island Jewish Health System. 

Out of roughly seven million antipsychotic prescriptions written for children, adolescents and teens in 2010, only 29 to 39 percent came from a child and adolescent psychiatrist, he noted in the editorial. “I was most surprised by the fact that the majority of youth receiving antipsychotics did not have a mental disorder diagnosis,” Correll told Reuters Health by email.

The study also exposed a gender gap, with prescriptions for boys outpacing girls during elementary, high school and college years. “The peak use among adolescent boys, who are frequently diagnosed with ADHD and are also treated with stimulants, strongly suggests that antipsychotics are commonly used to treat impulsive aggression and other behavioral symptoms,” Olfson said.

Before parents agree to start their child on antipsychotics to manage aggressive behavior, they should ask about alternative treatments such as anger management, counseling for parents on how to respond to aggression, and other psychosocial options, he said. “The main takeaway for clinicians and families is that for youth without psychiatric symptoms, alternatives to antipsychotic treatment should be tried whenever possible,” Correll said. “When antipsychotics are used, the lowest risk agents should be used for the shortest time possible.”

Source: Fox News