How does stress tip the balance between health and illness? That's the question that has been preoccupying scientists concerned with the ways our bodies respond to psychological trauma. According to a review of research published in the May 25 issue of Chemical & Engineering News, from the American Chemical Society, stress triggers an "exquisite repertoire" of events by attacking the body's delicate biochemical equilibrium. If the brain, along with the endocrine and immune systems, fails to restore that equilibrium, debilitating illness is the inevitable result. "Stress may be the thing that takes a part of our body that was marginally damaged by exposure to God-knows-what sort of toxins and pushes it into overt disease," speculates Robert Sapolsky of Stanford University.
It's a conclusion based on a number of findings with far-reaching consequences for the future treatment of stress-related disorders. Such disorders range from nervous breakdowns to World War I "shell shock". More recently, a White House-appointed committee has cited "post-traumatic stress disorder" as a factor in the mysterious Gulf War Syndrome.
Nodding towards the recent evolution of a field of science called psychoneuroimmunology, the report confirms that the brain and immune system are inextricably linked. When the body faces stress, the two spring into action as an integrated defence system. Interestingly, an individual's perception of the situation - how severe or stressful it seems to be - is said to play a role in determining the effectiveness of this system.
Other factors include previous experience of dealing with stress (one can, in some ways, learn to cope), and the duration of the stress response itself. A properly functioning feedback mechanism ensures that the response is limited, say the researchers. If it is not shut down, the continued production of the steroid cortisol eventually damages the hippocamus - the site of learning, consolidated memory and emotion.
Even so, not all stress is bad. Challenges to the body's biochemical equilibrium can be vital to get us out of a sticky situation. They also play a role in emotional and intellectual growth. And as Tracey Shors of Princeton University has shown, "some stress actually enhances the ability to learn, but only in males."
