Many biological theories of psychopathology suggest that mental illnesses occur when genetic predisposition to develop a disorder (diathesis) is combined with an environment that triggers its development ( stress). These are often called diathesis-stress models. A new series of studies from Concordia University has found evidence of a link between a recent rise in depression rates and the increase of daily stress.

An interesting piece of research has shown that there are marked sex differences in the ability to read facial expressions while under stress. This may be another factor in explaining why men are more likely to get into fights than women.

Video interview with stress researcher Hans Selye...

When Hans Selye was conducting research on rats by injecting them with extracts of various glands of the body, he noticed that the rats were all displaying the same group of symptoms. At first he believed that he had discovered a new hormone; however, after several years of further testing by injecting the rats with other substances, such as formaldehyde revealed the same results. Even exposure to cold, cutting their spinal cords and forced exercise produced the same effects. The effects occurred in a predictable sequence that is now known as the General Adaptation Syndrome (GAS).

Because there are individual differences in what is considered stressful, psychologists distinguish between stressors (the object, situation or person that causes a state of stress) and the stress-response (the physiological, emotional and behavioural effects).

stress has been shown to have a negative effect on the immune system in many studies; for example, Kiecolt-Glaser et al (1984) found that exam stress reduced the function of important immune cells; other studies have shown that wounds are slower to heal when people are suffering from stress. Now new research by Rita Effros, professor of pathology and laboratory medicine at the David Geffen School of Medicine at UCLA, and a member of the Jonsson Cancer Center, Molecular Biology Institute and UCLA AIDS Institute may explain how stress ages the immune system.

A new study has identified social/psychological factors in early childhood that can contribute to symptoms of anxiety and depression later in life. According to the doctorate study from the Norwegian Institute of Public Health (NIPH), small children who grow up in a family where the mother has psychological distress, the family is exposed to stress or is lacking social support, are at higher risk of developing anxious and depressive symptoms in early adolescence. Girls are more vulnerable than boys, and very timid or short-tempered children are more vulnerable than others to develop emotional problems.

It isn't just adults who suffer from the effects of stress; a recent study in Germany has shown that stress can have long term effects on children.

Researchers at the University of Texas Southwestern Medical Center have carried out research that may have implications for our understanding of stress, depression and eating disorders. It may also help explain why some people overeat when they are stressed or depressed.

Photo credit The University of Pennsylvania School of Medicine is reporting research published in the journal Social cognitive and Affective Neuroscience that shows that different parts of the brain are activated in males and females when confronted with a stressful situation. The researchers examined the activity of participant's brains using fMRI and measured levels of cortisol while they attempted difficult arithmetic problems (high stress) or counted backwards (low stress).