Causes of Stress

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Causes of Stress

So, what causes the stress that can be so bad for you?

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Some people may have a nervous system that goes into a stress reaction more readily than others. This could be due to individual differences in genetics and brain chemistry.

To try to understand stress better, we need to consider the psychological factors involved - emotional and cognitive (thinking) factors.

Research has suggested that major stressors in our lives are life changes, for example, moving house, marriage or relationship breakdown. Work-related factors, including unemployment and boredom, are also common causes of stress. Differences in personality may also play a part.

A stress reaction is a response to a perceived threat. Different people perceive things in different ways, so a situation that one person finds very stressful might not be to someone else.

The next Learn-it look at some of these major factors in turn.

In 1967, Holmes and Rahe came up with the idea of a 'social readjustment rating scale' (or SRRS for short). This was an attempt to quantify life change - any change in your life that might cause stress.

Scores are calculated for a person's experiences over the past year. Studies using the scale have found that high life change scores (300+) are related to relatively high frequency of illness, accidents and athletic injuries.

The table below shows a few life changes identified by Holmes and Rahe as serious stressors.

See if you can place the events shown in order of stressfulness, the top of the list, with highest scores being assumed to be the most stressful:

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You might be surprised to see Christmas and holidays in there, but they can really be seriously stressful for many people.

Other research in the 1990's showed a correlation between high levels of negative life events with increased vulnerability to colds.

The trouble with this 'social readjustment rating scale' is that it does not account for the fact that some people will find the same sort of event less stressful than others - for example, divorce could be perceived as a relief or a disaster. We cannot give reliable predictions about risks of stress-related illness based on this scale.

Lazarus and colleagues in the 1980's came up with a different stress measurement scale called the 'hassles and uplifts scale'. They claimed that, rather than major life changes, it is day-to-day hassles or small uplifts that determine our overall levels of stress.

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It has been found that high scores on 'hassles' - for example, being stuck in traffic or minor arguments with partner - correlated with symptoms of anxiety disorders and depression.

In the 1970s, Friedman and Rosenman carried out a nine-year study of 1000 people to try to find out if personality type affected stress levels. They came up with the idea of the 'Type A' personality - illustrated below:

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The typical 'type A' person is competitive, time-conscious, 'workaholic' and easily frustrated with others. Researchers have suggested that this sort of person would be likely to show more risky behaviour such as smoking, poor diet and so on.

257 men in their study died from heart attacks - 70% of those who died had been judged as having 'type A' personalities.

Critics have argued that it is very difficult to decide if someone has a 'type A' personality or not.

They also say that the connection between personality and heart disease is weak, maintaining that negative emotions such as anger and frustration are more linked to stress-related illness than 'workaholic' lifestyles. These emotions may not be fixed aspects of someone's personality.

In the late 1970's, Kobasa came up with a theory of why some people suffer stress more easily than others, suggesting that some people are 'hardy personality types'.

These people have a sense of personal control over their lives, a sense of purpose and they view life events as challenges rather than stresses. Such people report less stress-related illness.

Other research suggests that 'type A' people are not more vulnerable to stress than others, so other factors must play a part, for example:

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Does being in control mean more stress or less?

Brady carried out a notorious experiment in the 1950s called 'the executive monkey experiment' to see how 'executive stress' was related to control of a situation. Stress was measured by the amount of stomach ulcers suffered by the monkeys when placed in conditions in which they were given repeated electric shocks at regular intervals.

Brady found that 'executive monkeys', who had the power to turn off the electric shocks, developed greater ulceration than 'passive monkeys' who were dependent on their 'executive' partners to stop the shocks for them.

Weiss, however, repeated this study with rats using a warning bell to let them know when a shock was about to arrive - giving them an extra level of control - this was found to reduce stress-related symptoms.

Think a bit - what would you conclude from these 'executive stress' experiments?

In the 1970s, Seligman carried out another control-related study and came up with the idea of 'learned helplessness'.

Seligman found that when animals had experienced inescapable electric shocks, they did not escape later even when they were given the chance to.

This phenomenon also occurs in humans in response to loud noise. Seligman's work suggested that if life seems uncontrollable, it could lead to symptoms of depression - and depression is often stress-related.