Saturday, May 7, 2011

How Brain Chemistry Can Lead to Anxiety Disorders Discovered

EU-funded researchers have linked a previously unknown pathway in the brain to our response to stress, fuelling our understanding of the role 'brain chemistry' plays in how we react to highly stressful and traumatic events.

Illustration of this article

Presented in the journal Nature, the research was funded in part by the BRAIN AND ANXIETY and GENADDICT projects under the EU's Sixth Framework Programme (FP6). BRAIN AND ANXIETY ('Neural mechanisms of fear and anxiety: interactions between proteases and extra-cellular milieu') was backed with a Marie Curie Excellence Grant worth EUR 1.72 million and GENADDICT ('Genomics, mechanisms and treatment of addiction') received EUR 8.1 million under the 'Life sciences, genomics and biotechnology for health' Thematic area. The findings could help foster the treatment and prevention of stress-related psychiatric disorders.

Led by the University of Leicester in the United Kingdom, researchers shed new light on a long-standing mystery: why a minority of people experiencing traumatic events develop anxiety disorders. Anxiety disorder affects around 2 out of 10 people at least once in their lives. While the cumulative lifetime prevalence of all stress-related disorders is hard to pin down, experts believe it tops the 30% mark.

'Stress-related disorders affect a large percentage of the population and generate an enormous personal, social and economic impact,' explains Dr Robert Pawlak of the University of Leicester, a co-author of the study and recipient of the Marie Curie Excellence Grant. 'It was previously known that certain individuals are more susceptible to detrimental effects of stress than others. Although the majority of us experience traumatic events, only some develop stress-associated psychiatric disorders such as depression, anxiety or post-traumatic stress disorder. The reasons for this were not clear.'

According to Dr Pawlak, the team was intrigued to determine what makes some people more vulnerable to stress than others because little was known about the correlation between psychological trauma and development of pathological anxiety.

'We asked: What is the molecular basis of anxiety in response to noxious stimuli?' says Dr Pawlak. 'How are stress-related environmental signals translated into proper behavioural responses? To investigate these problems we used a combination of genetic, molecular, electrophysiological and behavioural approaches. This resulted in the discovery of a critical, previously unknown pathway mediating anxiety in response to stress.'

The amygdala, what experts call the brain's emotional centre, reacts to stress by intensifying the production of a protein called neuropsin. This kick-starts a series of chemical events which in turn cause the amygdala to boost its activity. This in effect activates a gene that determines the stress response at a cellular level.

'We then examined behavioural consequences of the above series of cellular events caused by stress in the amygdala,' says Dr Pawlak. Feelings of stress lead to avoidance of stressful events, but when proteins produced by the amygdala are blocked, behavioural consequences of stress are absent. 'We conclude that the activity of neuropsin and its partners may determine vulnerability to stress,' he explains.

Commenting on the results of the study, lead author Benjamin Attwood of the University of Leicester says: 'It has been a thoroughly absorbing project to uncover how our experiences can change the way we behave. Hopefully this will lead to help for people that have to live with the damaging consequences of traumatic experiences.'

Dr Pawlak concludes: 'We are tremendously excited about these findings. Although research is now needed to translate our findings to the clinical situation, our discovery opens new possibilities for prevention and treatment of stress-related psychiatric disorders such as depression and post-traumatic stress disorder.'

Experts from the Polish Academy of Sciences and the Japan-based Nara Institute of Science and Technology contributed to this study.
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1 comment:

  1. Thanks for sharing this information, For decades, scientists have believed that Stress and anxiety is related to abnormalities in brain chemistry. They base this conviction on the effects of drugs that reduce anxiety by increasing the availability of certain neurotransmitters in the brain.