We now know that placebo is, very definitely, an active treatment condition

Dr Andrew Leuchter

It may be that simply believing that you are receiving help is enough to stimulate a positive response.

Researchers from the University of California Los Angeles have used imaging technology to show that placebo treatment can actually change the way these people's brains work.

The changes are different to those found in people who respond to recognised antidepressant medication.

The researchers used a technique called quantitative electroencephalography to examine the electrical activity of the brain.

Area stimulated

Patients who responded to placebo showed increased activity in the brain's prefrontal cortex.

In contrast, those who responded to medication showed suppressed activity in that area.

The prefrontal cortex has been linked to working memory, information processing, behavioural organisation and attention.

Researcher Dr Andrew Leuchter said: "People have known for years that if you give placebos to patients with depression or other illnesses, many of them will get better.

"What this study shows, for the first time, is that people who get better on placebo have a change in brain function, just as surely as people who get better on medication.

"We now know that placebo is, very definitely, an active treatment condition."

New treatments

The researchers believe their work could eventually help determine which treatments work best in individual patients, and also could aid development of new medications.

Dr Leuchter said: "These findings show us that there are different pathways to improvement for people suffering from depression.

"Medications are effective, but there may be other ways to help people get better.

"If we can identify what some of the mechanisms are that help people get better with placebo, we may be able to make treatments more effective."

In total, 51 volunteers with serious depression took part in the study.

Overall, 10 out of the 26 patients who were given a placebo responded positively to the treatment. Thirteen out of the 25 who received a recognised antidepressant, either fluoxetine or venlafaxine, responded.

Thirteen of 25 of the subjects receiving antidepressant medication responded to treatment, while 10 of 26 of those receiving placebos responded.

The research is published in the American Journal of Psychiatry.