ABSTRACT
Introduction This chapter provides a brief overview of the current evidence base for cognitive behavioural therapy as applied to each of the major disorder areas outlined later in the book. The review is not a formal systematic review in that we have not presented all potential papers relevant to the diagnostic areas. Rather we have attempted to present the major points and provide key references where more detailed information can be accessed. In addition, the most up-to-date guidelines from the National Institute of Health and Clinical Excellence (NICE), at least those that apply to CBT, are also outlined. These are likely to exert increasing influence on treatment provision in the future - certainly within the UK. Because the NICE guidelines are constantly evolving, the authors recommend that the reader checks the current guidelines at nice.org.uk, as the information outlined in this chapter may become superseded with subsequent versions of the published NICE guidelines. After the major NICE recommendation points have been outlined, we include ratings for the strength of supporting evidence that NICE provide for each recommendation point. For example, in the NICE guidelines on depression (2004a) there is a recommendation point that treatment-resistant depression should be treated with a combination of medication and CBT. The evidence that supports this recommendation point is at a 'B' level rating. The NICE guidelines draw on a number of different quality 'levels'. These in turn draw on different categories of evidence. Both the levels of strength of evidence and the categories of evidence on which they are based are described in Box 4.1.
