A Swedish study in rats has uncovered a biological mechanism that increases the strength with which fear-associated memories are stored in the brains of people with anxiety-related disorders.
- Anxiety is a natural physiological phenomenon: in response to danger or stress, the functioning of our body changes. When these reactions become too intense or invasive, to the point of disrupting daily life, we speak of an anxiety disorder.
- 21% of adults will have an anxiety disorder at some point in their life. Women are up to twice as affected as men (source: Inserm.fr).
Being afraid is an essential ability for escaping potentially dangerous situations and learning to avoid them throughout life. But, in some conditions like post-traumatic stress disorder (PTSD) and other anxiety disorders, fear responses can become excessive and persist. This triggers intense anxiety, even though the danger is no longer present, and leads to disability for the person affected.
People with anxiety disorders have a different brain than others
Researchers suspect that some people have a greater tendency to develop pathological fears and that this is caused by malfunctions in the way the brain processes memories associated with fear. Certain areas of the brain are particularly important for the processing of this type of memory. The network of nerve cells that connects the frontal lobes to the amygdala, an area of the brain that regulates our actions in the face of danger, is notably involved in the brain’s responses to fear. The connections between these brain structures are also altered in people with PTSD and other anxiety disorders. However, even if we know the cerebral areas involved, the mechanisms behind them have long remained unknown.
The PRDM2 protein, a key to understanding the mechanisms of anxiety disorders
However, in a new study performed on rats and published in the journal Molecular Psychiatry, researchers at Linköping University, Sweden have discovered a biological mechanism that increases the strength with which memories associated with fear are stored in the brain. They studied a protein known as PRDM2, an enzyme that suppresses the expression of many genes. They analyzed the effects of reduced levels of PRDM2 on how memories associated with fear are processed by the brain. Previously, they found that PRDM2 levels were lower in alcohol-dependent people and led to exaggerated stress responses.
The authors of the study suggest that a drop in the level of PRDM2 makes it possible to reinforce the consolidation of memories associated with fear, making them last longer. In effect, this causes an increase in the activity of the nerve cells that connect the frontal lobes and the amygdala.
This discovery could, in the long term, improve treatments for people suffering from anxiety disorders if research on the subject is thorough.