Two profs tackle anxiety
January 1, 2002 - Three per cent of the population experience anxiety so crippling that it stops them in their tracks. However, knowledge of what causes these 'anxiety attacks' is increasing, and two University of Alberta professors are among the leaders in trying to solve the mystery.
Research has now shown that there is a direct link between panic and anxiety disorders and a neurotransmitter known as GABA that is prevalent throughout the brain. "Research in animals shows that early life stress seems to reduce the activity of the GABA system," says AHFMR Clinical Health Investigator and psychiatrist Dr. Nick Coupland, a specialist in anxiety disorder and depression at the U of A. "There are changes in GABA function in the parts of the brain that may regulate stress responses. We're interested to know if this is true in humans as well, and if this plays a part in how early life stress predisposes people to depression and anxiety."
To test this hypothesis, Coupland has recruited volunteers who suffer from panic disorder, along with a control group of individuals for whom anxiety is not a significant problem. He "challenges" the participants by giving them a medication called flumazenil. "About 50 per cent of the people who tend to have panic attacks will have one in response to the agent, whereas the healthy people don't," says Coupland. "There are lots of other measures that should change in a certain way if the attack is a chemical effect, so we should be able to see whether it's due to a chemical effect or a psychological mechanism."
Separate research with the University of Alberta's Department of Biomedical Engineering is developing measures of the levels of GABA in the brain using an imaging technique known as NMR spectroscopy, which will then be used to study differences in patients with anxiety and depression.
Female hormones and anxiety
The research interests of Dr. Jean-Michel Le Mellédo, another psychiatrist–researcher at the U of A, focus on anxiety and mood disorders. More specifically, he is interested in three areas that frequently overlap: mood and anxiety, the cardiovascular system, and sex hormones.
The AHFMR Population Health Investigator is an expert on premenstrual dysphoric disorder (PMDD), the significant mood, behavioural, and physical symptoms associated with the menstrual cycle. Not all women suffer from PMDD, but those who do are at high risk of more serious behavioural or psychiatric problems, such as major depression, anxiety disorders and postpartum depression. Fluctuations of the female hormone progesterone and a related hormone, allopregnenolone, during the menstrual cycle affect the GABA system and may contribute to the symptoms of PMDD.
Le Mellédo uses flumazenil to challenge the GABA system in women with the disorder during the beginning of the menstrual cycle (when premenstrual symptoms are absent) and during the days before the menses (when premenstrual symptoms are present). His purpose is to determine if the GABA system in women with PMDD is deregulated during the whole menstrual cycle or only when they experience premenstrual symptoms. In collaboration with Dr. Glen Baker, a neurobiochemist at the University of Alberta, he also compares allopregnanolone levels of women who suffer from PMDD with those of unaffected women, to see if the women with PMDD have lower levels of this naturally occurring anti-anxiety agent.
"PMDD is an ideal way to study the relationship between mood and anxiety and the hormonal changes that are occurring," says Le Mellédo. "In two weeks, women who suffer from PMDD reach a state of perfect well-being. Then, within two weeks, they are in a state of anxiety and distress. It's important to know exactly why this is happening, so we can develop new treatments for the many women who suffer from the disorder."
Dr. Nick Coupland is a Heritage Clinical Investigator, Assistant Professor of Psychiatry at the University of Alberta, and Director of the Psychopharmacology Research Unit. The CIHR, the Canadian Psychiatric Research Foundation, and the University of Alberta Hospital Foundation also support his research.
Dr. Jean-Michel Le Mellédo is a Heritage Clinical Investigator, Assistant Professor in Psychiatry at the University of Alberta, and Director of the Mood and Anxiety Research Unit. His research is also supported by the CIHR and the University of Alberta Hospital Foundation.
This article originally appeared in fall 2001 edition of Research News, the AHFMR quarterly magazine.
Related link – internal
The U of A Department of Psychiatry Web site: http://www.psychiatry.ualberta.ca/
Related link – external
The Alberta Heritage Foundation for Medical Research Web site: http://www.ahfmr.ab.ca./
Experts mentioned in this article
