When does stress cause illness?

Both humans and animals have different reactions to stress. Ongoing exposure to stress causes some individuals to show symptoms of disease, while others are resilient and do not become ill. For a long time, the reasons behind these different reactions have been unclear.

Researchers use the labyrinth test to gauge the anxiety of a mouse. CREDIT: Max Planck Institute of Psychiatry

Now, scientists working with mice at the Max Planck Institute of Psychiatry have identified the molecular composition of the AMPA receptor, a common binding site in the central nervous system, as a possible cause of the differences.

The neurotransmitter glutamate, which is responsible for the mediation of nerve impulses, binds to this receptor. In future, this discovery may help to predict individual risk for stress-related diseases. (Journal of Neuroscience, Advance online publication, December 15, 2010)

Everyone reacts differently to stress: While ongoing strain or even a one-off, highly stressful situation, for example a traumatic experience, may give rise to a psychiatric illness such as depression or post-traumatic stress disorder in some individuals, others remain healthy.

In all this, resilience to stress is largely determined by an individual's biological make-up. However, the molecular mechanisms involved have been largely unknown to date.