Positive effects of CBT eroded over time
News release from the National Coordinating Centre for Health Technology Assessment
18 November 2005
New research commissioned by the HTA programme suggests that the short term benefits of cognitive behaviour therapy (CBT) for mental illness may not be sustained for longer periods of time. Existing research evidence suggests that the benefits of CBT last for up to a year following the end of a course of treatment. The newly published study aimed to determine whether these known short term benefits endure over longer periods of time by conducting long-term follow up with people who took part in a series of clinical trials to investigate CBT for the treatment of anxiety disorders and psychosis. Following up with the participants of the trials between two to 14 years after the original treatment, the researchers found that over half of those monitored were still diagnosed with some form of mental illness, and very few had none or only mild symptoms.
Led by Dr Rob Durham, senior lecturer in clinical psychology at the University of Dundee , the research team talked to the participants of 10 clinical trials which were conducted by the same research team between 1985 and 2001. Eight of the trials investigated the use of CBT to treat anxiety disorders, and two trials looked at CBT to treat psychosis, specifically schizophrenia. The research team talked to almost half (489) of the 1071 participants of the trials, conducting follow up interviews with them between 2 to 14 years after the completion of the trials using a research psychologist and psychiatric nurses.
The researchers found that, of those who took part in the anxiety disorder trials, over half were diagnosed with at least one associated medical condition at long term follow up, with significant numbers suffering from more than one related condition and low health status scores. Few of the participants had none or only mild symptoms and a significant proportion (over a third) had symptoms of at least moderate severity. Only 36 per cent reported receiving no interim treatment over the follow-up period, and 19 per cent said that they had received almost constant treatment. Of those who took part in the psychosis trials nearly all participants (93%) reported almost constant treatment over the follow-up period at a significantly higher level than the anxiety disorder patients.
Overall the research team found that treatment with CBT was associated with slightly higher costs than non-CBT, and slightly higher benefits. The team found that the costs of providing CBT in the original trials were only a very small proportion (6.4%) of the overall costs of healthcare for the patient population, which are generally high for both physical and mental health problems.
The research team concluded that while CBT has clear short-term benefits in the treatment of common mental health problems such as panic disorder and generalised anxiety for up to 12 months after treatment, long term benefits from CBT are not guaranteed. Treatment with CBT was associated with a better long term outcome than non-CBT in terms of overall symptom severity but not with regard to diagnostic status, and the positive effects of CBT identified in the original trials were found to have eroded over longer time periods. No evidence was found to suggest an association between more intensive therapy and more enduring effects of CBT.
"CBT has been shown to be an effective treatment for a wide range of mental health disorders and has an important place in the treatment of anxiety disorders in primary and secondary care," says lead researcher Dr Rob Durham. "Because anxiety disorders tend to follow a chronic course it is important to investigate whether or not the benefits of this therapy are sustained over extended periods of time. Our research indicates that long-term benefits following one course of CBT should not be assumed. Factors associated with the complexity and severity of the original problem, whether treatment was completed, and the amount of interim treatment received during the follow-up period, were more strongly related to long-term outcome than the type of treatment received in the original trials. This information can be used to improve the delivery and quality of CBT to ensure more enduring changes in vulnerable individuals."
Notes:
CBT is a problem oriented method of psychological treatment applicable to a wide variety of clinical problems in psychiatry and general healthcare. It has a broad application, with an emphasis on practical coping skills.
This research features in Health Technology Assessment Vol 9.42 , the internationally acclaimed journal of the HTA programme, http://www.hta.ac.uk/project/1081.asp
Notes for editors
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The HTA programme is a programme of the National Institute for Health Research (NIHR) and produces high quality research information about the effectiveness, costs, and broader impact of health technologies for those who use, manage and provide care in the NHS. It is the largest of the NIHR programmes and publishes the results of its research in the Health Technology Assessment journal, with more than 400 issues published to date. The journal’s 2007 Impact Factor (3.87) ranked it in the top 10% of medical and health-related journals. All issues are available for download free of charge from the website, www.hta.ac.uk The HTA programme is coordinated by the National Coordinating Centre for Health Technology Assessment (NCCHTA), based at the University of Southampton.
- The National Institute for Health Research provides the framework through which the research staff and research infrastructure of the NHS in England is positioned, maintained and managed as a national research facility. The NIHR provides the NHS with the support and infrastructure it needs to conduct first-class research funded by the Government and its partners alongside high-quality patient care, education and training. Its aim is to support outstanding individuals (both leaders and collaborators), working in world class facilities (both NHS and university), conducting leading edge research focused on the needs of patients. www.nihr.ac.uk
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