The causes of stress can be either biological or psychosocial and the effects of stress on feelings and behaviour can be either positive or negative.

Stress can also be classified in terms of its duration into acute stress, episodic stress or chronic stress.

Acute Stress
Acute stress is a response to something in the recent past, present or immediate future that is perceived as demanding. For example the immediate response a person might have to finding out he has lost an important client; is likely to be made redundant or has an impending job interview.

The acute stressor may be perceived as being a positive opportunity or as a negative event depending on the person’s perception of his resources to meet the demands of the situation.

For example, an impending job interview might typically be viewed as a positive opportunity provided the person feels prepared, and believes that she has a reasonable chance of being awarded the job.

However a person who believes that she is terrible at interviews and that she is bound to make a fool of herself may well consider the impending interview as a potential threat. This is because she does not expect to be offered the job and fears having to deal with her feelings of embarrassment and rejection in the near future. The degree of stress she feels will be further moderated by her beliefs about her ability to cope with embarrassment and rejection.

Negative events may be either potential threats, in which there is there the potential in the near future for emotional and maybe even physical hurt, or harm / loss situations in which the damage has already occurred.

Whether the acute stress is ultimately perceived as positive or negative people usually remain aware of their physical and emotional responses to acute stress.

Episodic Stress
Episodic stress is recurrent exposure to acute stress.

If someone repeatedly encounters acutely stressful situations with inadequate recovery in-between he may become permanently ‘on edge’ i.e. waiting for the next stress inducing problem.

People suffering episodic stress often become less aware of the physical symptoms of each specific episode of acute stress and may start to suffer more generalised physical symptoms such as palpitations, headaches, sweating, reduced appetite and disturbed sleep.

They might also experience psychological changes such as irritability, anger, excessive worry and sadness.

Often the problems of episodic stress are compounded as people start to adopt less healthy ways of coping with the stress symptoms such as drinking more alcohol, comfort eating, withdrawing from social contact, overworking and neglecting exercise.

Since the body has little chance to recover from the repeated triggering of the stress response this can lead to the exhaustion stage of the general adaptation syndrome.

Chronic Stress
Chronic stress refers to the impact of a long-term challenging situation or set of circumstances which exceeds the coping resources of the sufferer. Chronic stress is very often associated with exhaustion and feelings of helplessness. Sometimes people suffering from chronic stress don’t realise the extent of their problem as feeling stressed has become the norm.