Monaz: Hello, I'm Monaz Mehta, editor in the Cochrane Editorial and Methods department. Chronic pain is a major problem for many people, and it's important to have up-to-date evidence on the effects of possible treatments. With that in mind, we published the third update of the Cochrane Review of psychological therapies for chronic pain in August 2020 and here's lead author, Amanda Williams from University College London in the UK to tell us about the latest findings.

Amanda: Chronic pain is very common, increasing in incidence with age, and seriously affecting quality of life. It's pain that doesn't signal damage or disease, but is maintained by nervous system changes and is mostly unresponsive to painkillers or other medical interventions.
Over the longer term, the usual ways of managing pain such as analgesics and medical help, and taking rest, can cause disability and often depression; but these problems are to some extent reversible by changes to the approach for pain management. Using psychological therapy is one way to do this, by a combination of understanding pain, reducing anxiety about its meaning, increasing activity in whatever way is important to the individual, and improving overall quality of life. This can help people return to social activities, leisure pursuits, work, and become more independent of health care.
Psychological therapies come in various forms, and we separately analysed the three most common in our review. These are cognitive behavioural therapy (CBT), behaviour therapy (BT), and acceptance and commitment therapy (ACT). We were interested in all types of chronic pain except headache, for which treatment is somewhat different, and we required the treatments to have been face to face and for the studies to have at least 20 people remaining in each trial arm at the end of treatment. We analysed outcomes of pain, disability, and distress, and although we looked for evidence of adverse effects, it was too scant to analyse.
Of the 75 trials we included, 59 tested CBT. These showed small benefits in pain, disability, and distress compared to no treatment, which was mostly maintained at 6 to 12 months follow-up. There were very small benefits when the CBT was compared to an alternative such as education and exercise, and this was not maintained at follow-up. 
There were 8 studies of BT, with no evidence of benefit, but this is an area in which more and larger trials with clearly defined treatment components would be particularly helpful.
The big surprise to use was finding only 5 studies of ACT, which has become a popular choice to offer people with chronic pain, both here in the UK and elsewhere. The quality of this evidence was low and we had no confidence in the findings, which were mainly of no difference between ACT and control treatments. This means that we urgently need large high-quality trials of ACT, preferably done by therapists who are even-handed in their delivery of ACT and of the control treatment. While we await such trials, ACT should be regarded as an experimental therapy, and evaluated whenever it is used.
In summary, there are sufficient large trials of CBT to have reasonable confidence that it brings benefits to patients with chronic pain, although these benefits are small on average. Looking to the future, we need to try to find ways to make those benefits larger, and to extend them to populations often excluded from trials, such as people with cognitive impairment or psychiatric problems.

Monaz: To read the full version of the current review, and watch for the next update, you can find it at Cochrane Library dot com. If you go to the website and simply search 'psychological therapies for chronic pain' it will be listed near the top.