Showing that life events are a cause of depression--a review

Some necessary conditions are set out for showing that some quality of life events is a cause of depression. Recent advances in method which help to fulfil these conditions are reviewed in the fields of life events, depression and survey design. Studies which may have been regarded as refuting a causal link between life events and depression are analysed in detail and their conclusions are challenged. Studies which have claimed a causal link have used methods which in general fulfil the conditions for showing a cause. It was concluded that the hypothesis that severely unpleasant life events, particularly events involving loss, are a cause of depression has not been refuted. Furthermore, a number of studies have accumulated evidence for such a causal link. The weaknesses of these studies are discussed. Improved methods are suggested for use in future research.