Cannabis damages young brains more than originally thought
December 20, 2009
Science Daily/McGill University Health Centre
Canadian teenagers are among the largest consumers of cannabis worldwide. The damaging effects of this illicit drug on young brains are worse than originally thought, according to new research by Dr. Gabriella Gobbi, a psychiatric researcher from the Research Institute of the McGill University Health Centre. The new study, published in Neurobiology of Disease, suggests that daily consumption of cannabis in teens can cause depression and anxiety, and have an irreversible long-term effect on the brain.
"We wanted to know what happens in the brains of teenagers when they use cannabis and whether they are more susceptible to its neurological effects than adults," explained Dr. Gobbi, who is also a professor at McGill University. Her study points to an apparent action of cannabis on two important compounds in the brain -- serotonin and norepinephrine -- which are involved in the regulation of neurological functions such as mood control and anxiety.
"Teenagers who are exposed to cannabis have decreased serotonin transmission, which leads to mood disorders, as well as increased norepinephrine transmission, which leads to greater long-term susceptibility to stress," Dr. Gobbi stated.
Previous epidemiological studies have shown how cannabis consumption can affect behaviour in some teenagers. "Our study is one of the first to focus on the neurobiological mechanisms at the root of this influence of cannabis on depression and anxiety in adolescents," confirmed Dr. Gobbi. It is also the first study to demonstrate that cannabis consumption causes more serious damage during adolescence than adulthood.
Dr. Gabriella Gobbi is a researcher at the neuroscience axis of the Research Institute of the McGill University Health Centre and also a psychiatrist and associate professor at the Department of Psychiatry, McGill University.
This study was funded by a grant from The Canadian Psychiatric Research Foundation (CPRF)
https://www.sciencedaily.com/releases/2009/12/091217115834.htm
Brain activity buffers against worsening anxiety
Activity in brain's thinking and problem-solving center linked to avoiding anxiety
November 17, 2017
Science Daily/Duke University
Boosting activity in brain areas related to thinking and problem-solving may also protect against worsening anxiety, suggests a new study. Using noninvasive brain imaging, the researchers found that at-risk people were less likely to develop anxiety if they had higher activity in a region of the brain responsible for complex mental operations. The results may be a step towards tailoring psychological therapies to the specific brain functioning of individual patients.
Using non-invasive brain imaging, the researchers found that people at-risk for anxiety were less likely to develop the disorder if they had higher activity in a region of the brain responsible for complex mental operations. The results may be a step towards tailoring psychological therapies to the specific brain functioning of individual patients.
"These findings help reinforce a strategy whereby individuals may be able to improve their emotional functioning -- their mood, their anxiety, their experience of depression -- not only by directly addressing those phenomena, but also by indirectly improving their general cognitive functioning," said Ahmad Hariri, a professor of psychology and neuroscience at Duke. The results are published Nov. 17 in the journal Cerebral Cortex.
Previous findings from Hariri's group show that people whose brains exhibit a high response to threat and a low response to reward are more at risk of developing symptoms of anxiety and depression over time.
In the current work, Hariri and Matthew Scult, a clinical psychology graduate student in the department of psychology and neuroscience at Duke, wanted to investigate whether higher activity in a region of the brain called the dorsolateral prefrontal cortex could help shield these at-risk individuals from future mental illness.
"We wanted to address an area of understanding mental illness that has been neglected, and that is the flip side of risk," Hariri said. "We are looking for variables that actually confer resiliency and protect individuals from developing problems."
The dorsolateral prefrontal cortex is our brain's "executive control" center, helping us focus our attention and plan complex actions. It also plays a role in emotion regulation, and well-established types of psychotherapy, including cognitive behavioral therapy, engage this region of the brain by equipping patients with strategies to reframe or re-evaluate their emotions.
The team drew on data from 120 undergraduate students who participated in the Duke Neurogenetics Study. Each participant completed a series of mental health questionnaires and underwent a type of non-invasive brain scan called functional Magnetic Resonance Imaging (fMRI) while engaged in tasks meant to activate specific regions of the brain.
The researchers asked each participant to answer simple memory-based math problems to stimulate the dorsolateral prefrontal cortex. Participants also viewed angry or scared faces to activate a region of the brain called the amygdala, and played a reward-based guessing game to stimulate activity in the brain's ventral striatum.
Scult was particularly interested in "at-risk" individuals with the combination of high threat-related activity in the amygdala and low reward-related activity in the ventral striatum. By comparing participants' mental health assessments at the time of the brain scans, and in a follow-up occurring on average seven months later, he found that these at-risk individuals were less likely to develop anxiety if they also had high activity in the dorsolateral prefrontal cortex.
"We found that if you have a higher functioning dorsolateral prefrontal cortex, the imbalance in these deeper brain structures is not expressed as changes in mood or anxiety," Hariri said.
The dorsolateral prefrontal cortex is especially skilled at adapting to new situations, the researchers say. Individuals whose brains exhibit the at-risk signatures may be more likely to benefit from strategies that boost the brain's dorsolateral prefrontal activity, including cognitive behavioral therapy, working memory training, or transcranial magnetic stimulation (TMS).
But, the researchers warn, the jury is still out on whether many brain-training exercises improve the overall functioning of the dorsolateral prefrontal cortex, or only hone its ability to complete the specific task being trained. Additional studies on more diverse populations are also needed to confirm their findings.
"We are hoping to help improve current mental health treatments by first predicting who is most at-risk so that we can intervene earlier, and second, by using these types of approaches to determine who might benefit from a given therapy," Scult said.
https://www.sciencedaily.com/releases/2017/11/171117141743.htm
People at risk for panic buffered from stressor by high levels of physical activity
July 14, 2011
Science Daily/Southern Methodist University
People at risk for experiencing panic attacks respond with less anxiety to a panic-inducing stressor if they have been regularly engaging in high levels of physical activity, suggests a new study. High levels of physical activity appeared to buffer against panic-inducing stress -- inhalation of carbon dioxide-enriched air -- among people typically afraid of the nausea, dizziness, racing heart and shortness of breath that characterize panic episodes, according to psychologists
"Anxiety sensitivity is an established risk factor for the development of panic and related disorders," said SMU psychologist Jasper Smits, lead author on the research. "This study suggests that this risk factor may be less influential among persons who routinely engage in high levels of physical activity."
Regular exercise as an alternative or complementary strategy to drugs and psychotherapy
There is already good evidence that exercise can be of help to people who suffer from depression and anxiety problems, say the researchers. "We're not suggesting, 'Exercise instead of pharmacotherapy or psychotherapy,'" Smits said. "Exercise is a useful alternative, particularly for those without access to traditional treatments. Primary care physicians already prescribe exercise for general health, so exercise may have the advantage of helping reach more people in need of treatment for depression and anxiety."
http://www.sciencedaily.com/releases/2011/07/110712122403.htm
Increased anxiety associated with sitting down
June 19, 2015
Science Daily/BioMed Central
Low-energy activities that involve sitting down are associated with an increased risk of anxiety, according to new research. These activities, which include watching TV, working at a computer or playing electronic games, are called sedentary behavior.
Many studies have shown that sedentary behavior is associated with physical health problems like obesity, heart disease, type 2 diabetes and osteoporosis. However, there has been little research into the link between sedentary behavior and mental health. This is the first systematic review to examine the relationship between anxiety and sedentary behavior.
Anxiety is a mental health illness that affects more than 27 million people worldwide. It is a debilitating illness that can result in people worrying excessively and can prevent people carrying out their daily life. It can also result in physical symptoms, which amongst others includes pounding heartbeat, difficulty breathing, tense muscles, and headaches.
Megan Teychenne, lead researcher and lecturer at Deakin University's Centre for Physical Activity and Nutrition Research (C-PAN) in Australia, said: "Anecdotally -- we are seeing an increase in anxiety symptoms in our modern society, which seems to parallel the increase in sedentary behavior. Thus, we were interested to see whether these two factors were in fact linked. Also, since research has shown positive associations between sedentary behavior and depressive symptoms, this was another foundation for further investigating the link between sedentary behavior and anxiety symptoms."
C-PAN researchers analyzed the results of nine studies that specifically examined the association between sedentary behavior and anxiety. The studies varied in what they classified as sedentary behavior from television viewing/computer use to total sitting time, which included sitting while watching television, sitting while on transport and work-related sitting. Two of the studies included children/adolescents while the remaining seven included adults.
It was found in five of the nine studies that an increase in sedentary behavior was associated with an increased risk of anxiety. In four of the studies it was found that total sitting time was associated with increased risk of anxiety. The evidence about screen time (TV and computer use) was less strong but one study did find that 36% of high school students that had more than 2 hours of screen time were more like to experience anxiety compared to those who had less than 2 hours.
The C-PAN team suggests the link between sedentary behavior and anxiety could be due to disturbances in sleep patterns, social withdrawal theory and poor metabolic health. Social withdrawal theory proposes that prolonged sedentary behavior, such as television viewing, can lead to withdrawal from social relationships, which has been linked to increased anxiety. As most of the studies included in this systematic-review were cross-sectional the researchers say more follow-up work studies are required to confirm whether or not anxiety is caused by sedentary behavior.
Megan Teychenne said: "It is important that we understand the behavioral factors that may be linked to anxiety -- in order to be able to develop evidence-based strategies in preventing/managing this illness. Our research showed that evidence is available to suggest a positive association between sitting time and anxiety symptoms -- however, the direction of this relationship still needs to be determined through longitudinal and interventional studies."
http://www.sciencedaily.com/releases/2015/06/150619085534.htm