Investigations of Beck's cognitive therapy for depression

Abstract

Beck's cognitive model of depression suggests that negative thinking can play an important role in the development and maintenance of clinical depression. It follows from this that interventions which reduce the frequency or intensity of depressing thoughts will also reduce depression. This prediction forms the basis of cognitive-behavioural therapy (CBT) for depression, as developed by Beck and his colleagues.

The cognitive model of depression, and cognitive therapy, are described. The development of a questionnaire (the Cognitions Questionnaire -- CQ) is then presented, designed to assess various dimensions of depressive thinking in relation to positive, negative and neutral hypothetical events. Relationships between scores on the questionnaire and level of depression in psychiatric and community samples are examined, and possible indices of continuing cognitive vulnerability to depression following an episode are explored.

As an alternative to the traditional outcome trial, a within-subject experimental design is proposed, designed to test the central prediction of the cognitive model outlined above by examining the immediate effects on depressive thinking and on depression of specified cognitive therapy interventions. A series of experiments is presented, which demonstrated that in patients low in endogeneity, a brief, standardised distraction procedure reliably reduced the frequency of depressing thoughts, compared to a control procedure. As would be predicted from the cognitive model of depression, this was accompanied by significant reductions in depression. A study using non depressed student subjects showed that these effects could not be attributed to the direct impact of the two procedures on depressed mood. Similar results were not found in depressed patients high in endogeneity. The nature of this difference in responsiveness to distraction is explored, and its implications for the theory and practice of CBT for depression are discussed.