Psychological treatments may help lower the intensity of chronic low back pain, a review suggests.

Researchers evaluated 22 randomized trials published between 1982 and 2003 to evaluate the effects of psychological interventions on pain.

The approaches improve outcomes such as depression and health-related quality of life as well as patients' experience of pain, the team concluded in the January issue of the journal Health Psychology.

"Because this analysis was both more inclusive and more conservative than previous reviews, we have the best evidence to date that these interventions are helpful," said psychologist and review lead author Robert Kerns of the VA Connecticut Healthcare System.

The trials included adults with nonmalignant low back pain lasting at least three months, with an average duration of 7.5 years.

The approaches included self-regulatory treatments, such as hypnosis and relaxation, and supportive counselling.

The largest and most consistent effect was a reduction in pain intensity, the researchers found.

When the interventions were first developed, the goal was actually to help patients to live with their pain more successfully, not reduce it.

No psychological treatment offers a cure for people with chronic pain, but people may be expecting it, said Dennis Turk, a professor of anesthesiology and pain research at the University of Washington in Seattle.

The psychological interventions are cheaper than other treatments such as surgery and opioids, he said.

"The paradox is that, despite data on the effectiveness of psychological interventions, insurers are less willing to pay for them."