Cognitive behaviour therapy for primary insomnia: can we rest yet?

Cognitive behaviour therapy (CBT) for chronic insomnia has been a topic of interest to researchers and clinicians for over forty years. Investment in this area has paid off. Two meta-analyses and one major review by the Standards of Practice Committee of the American Academy of Sleep Medicine have concluded, beyond doubt, that CBT is effective in the treatment of primary insomnia. In this paper we argue that it is timely to raise new questions of CBT for insomnia: namely, is there still room for improvement? and can we rest yet? Whilst significant progress has been made we argue that the field is not, as yet, at a point where patients can be offered a maximally effective psychological treatment. Two lines of argument are developed to support this conclusion. First, it is noted that whilst the effect size for CBT for insomnia is moderate, it is lower than the effect sizes reported for CBT for a range of other psychological disorders. Second, it is suggested that the large literature outlining optimal procedures for conducting randomised controlled trials (RCTs) need to be more fully adopted by research workers in this field. Directions for future research are outlined including (1) guidelines for improved RCT methodology and (2) suggestions for developing empirically grounded treatments.