Describe and evaluate Selye's General Adaptation Syndrome (GAS) model.

Selye’s General Adaptation Syndrome (GAS) states that prolonged chronic exposure to stress can be harmful to an individual and suggest that individuals go through three physiological stages: alarm, resistance and exhaustion. In the alarm stage the individual I aware of the stressor and loses the ability to deal with the stressor therefore going into shock doe to the arousal of the autonomic nervous system (ANS). If the source of the stress is not dealt with immediately the individual enters into the resistance stage where the ANS attempts to return the body back to normal functioning. If resistance is not successful the next stage is exhaustion where the stress continues during this stage the individual loses the ability to adapt to the stressor, therefore more susceptible to illness or even death.

The GAS model explains how chronic stress has a negative impact on physical health and wellbeing as well as psychological health. It also challenges the theory that bacteria is the only cause for illness, by showing that stress weakens the immune system which increases susceptibility to illness. However, there are a few limitations, the GAS model was only conducted on animals and their responses to stress may differ to humans. The model also does not take into consideration individual differences in the way people view different stressors.