ABSTRACT
The evolutionary approach to emotion has been increasingly useful in understanding the origins of mental illness, just as evolutionary biology has been useful in improving our understanding of physical disorders like appendicitis and heart disease, or physical anomalies like the ‘blind spot' of the human eye. Sometimes we discover that what has previously been regarded as a disorder might actually be a defence against some other more threatening problem. For example, in the physical domain, we do not talk about 'diarrhoea disorder', ‘vomit disorder' or ‘cough disorder' - we have come to realise that these reactions are evolved defences. It is possible that depression may be a psychological defence against persistent stress. We have learnt that the experience of depression carries a lot of potential advantages that need to be capitalised on.
