But those patients in the trial who received cannabis with only cannabidiol (CBD) showed no relief at all, say medics at Dutch Leiden University Medical Centre.

A total of 20 patients participated in the study which was funded by Dutch medical cannabis maker Bedrocan. Investigators conducted a series of measurements and tests before and after three cannabis drugs and one placebo drug was administered to 20 patients.

In one test, a weight was placed on the muscle between the thumb and forefinger. Principal Investigator, Professor Albert Dahan, head of the Anaesthesia and Pain Research Unit of the Department of Anaesthesiology said: “Healthy people can handle ten kilograms.

“For a fibromyalgia patient, one kilogram is already painful. But after administering Bedrocan products with THC, we saw that the same patient could suddenly bear ten kilos. Fibromyalgia patients experience pressure pain on muscles and tendons especially. Because only Bediol and Bedrocan show good results and the CBD product Bedrolite not at all, it means that especially THC is effective in this specific condition.”

Researchers say further work is required to determine whether the same results on pain relief can be reproduced in a long-term study with fibromyalgia patients.