Beck's cognitive theory of depression assumes that people who become depressed have relatively enduring cognitive processes and structures which rendered them vulnerable to depression (Beck 1976). This assumption stands in contrast to more traditional views (e.g. Silverman et al. 1984) which consider negative thinking as only a symptom of depression. There has also been considerable confusion and contradiction among researchers as to what is meant by Beck's assertion that cognitive factors play an aetiological role in the development of depression. Some authors also seem to equate the terms precipitation and vulnerability. This results in a failure to distinguish between (a) cognitions as causes of concurrent affective, motivational and behavioural symptoms of depression and (b) cognitions as enduring vulnerability factors (Coyne and Gotlib 1983).