1.1 What do we mean by stress?
We tend to think of ‘stress’ as a state of demand that is likely to stretch us to breaking point, and hence as a bad thing, to be avoided. An image of stress this brings to mind is pulling on a chain with increasing force: sooner or later the chain will break at the weakest link, leading to collapse. However Hans Selye, the distinguished Austro-Hungarian endocrinologist who developed the concept of stress in the 1930s, felt this was a very one-sided view – he regarded stress as ubiquitous and vitally important, calling it ‘the salt of life’ (Selye, 1978 ).
Selye distinguished two kinds of stress:
Within the general concept of stress … we must differentiate between distress (from the Latin dis = bad, as in dissonance, disagreement), and eustress (from the Greek eu = good, as in euphonia, euphoria). During both eustress and distress the body undergoes virtually the same nonspecific responses to the various positive or negative stimuli acting upon it. However, the fact that eustress causes much less damage than distress graphically demonstrates that it is ‘how you take it’ that determines, ultimately, whether you can adapt successfully to change.
The distinction between eustress and distress is not current, but Selye and others found it helpful to understand how stress could be ‘good’ as well as ‘bad’.
The critical point that Selye was making is that an understanding of biology by itself may not be enough to understand the effects of stress because the same physiological mechanism underlies both positive and negative stress. Selye’s point about ‘how you take it’ is relevant to the concept of ‘appraisal’ which we cover later in Section 1.4.
Selye saw a stressor as anything eliciting the physiological stress or ‘emergency’ response. The stress response is elicited not just in a classic ‘fight or flight’ situation, but also when the body is fighting an infection, and in situations that are stimulating and enjoyable, such as ‘playing a game of tennis, or engaging in a passionate kiss’ (Selye, 1978 ; Figure 1). Emotions such as joy, anger and fear are potent elicitors of the stress response. Expectations play a part in generating stress too. Stress is present, for instance, if people believe – correctly or incorrectly – that something threatening or unpleasant is just round the corner.
Despite Selye’s broad definition of stress, when used in the context of emotional disorders, the term is generally taken to mean negative stress (or distress). Unfortunately it is virtually impossible to live a life free from this form of stress and whilst it has been suggested that the experience of mild to moderate levels of stress in early life may ‘inoculate’ animals and people against more serious stress later on (e.g. Maddi, 2006), severe or chronic stress can have very damaging effects, as you will see next.