'Placebo therapy' ineffective for long-term chronic pain relief

Scientists at the University of Liverpool have shown that 'placebo therapy' could be effective for short-term pain relief in patients with Complex Regional Pain Syndrome (CRPS), but does not have a lasting impact.

For the treatment of pain, the magnitude of a 'placebo-effect' – a combination of the pain getting better naturally and the brain believing that a dummy drug intervention can help – is thought to be as much as a 25% to 35% reduction in patient discomfort.

Alongside such an effective 'therapy', however, it is unclear what impact a 'real' drug treatment can have.

It is known that patients with a variety of health conditions often get better with placebo therapies, even though these have no specific health benefits – they simply 'look' like the real thing. Studies into irritable bowel syndrome, for example, have shown that patients improve with placebo 'treatment', and placebo is even discussed as a recommend course of therapy in some cases.

Clinical trials

The Liverpool team assessed the results of all clinical trials relating to long-term CRPS patients – a condition that can develop after small trauma to the limbs – conducted in the UK and internationally, to understand the effect of placebo therapy and how large the impact is on patients with the condition.

Dr Andreas Goebel, from the University's Institute of Translational Medicine, explains: We found that patients experienced significant pain relief minutes after a placebo therapy, such as salt water injections, but unexpectedly at a later time, and even with repeated placebo applications, there was minimal or no impact on reducing the symptoms of the condition."

The results suggest that CRPS will not improve naturally over time, and there is little fluctuation in the pain intensity of the condition.

Dr Goebel added: "It seems that the brain of CRPS patients cannot be easily 'tricked' into believing that a dummy intervention is effective. This means that health specialists should be cautious when considering placebo interventions for these patients."