A cannabis-based drug may help ease muscle movement for people suffering from motor neuron disease, the results of a clinical trial have shown.

The study, published in The Lancet Neurology journal, showed that chemical compounds -- delta-9 tetrahydrocannabinol THC and cannabidiol (THC-CBD) -- derived from the cannabis sativa plant given as an add-on treatment may help ease symptoms of spasticity (tight or stiff muscles).

Spasticity is a rapidly progressive, fatal neurodegenerative disorder affecting the nerve cells that control muscle movement. It is a major cause of disability and reduced quality of life in people with motor neuron disease. Adults with motor neuron disease who took a combination of anti-spasticity drugs and cannabidiol experienced less spasticity and pain at six weeks follow-up compared with those given placebo.

"There is no cure for motor neuron disease so improved symptom control and quality of life are important for patients," said lead researcher Nilo Riva from the San Raffaele Scientific Institute in Italy. "Our trial showed a beneficial effect of THC-CBD spray in people on treatment-resistant spasticity and pain," Riva added. 

However, there is a need to confirm efficacy and safety of THC-CBD spray in larger, longer term phase 3 trials, Riva said. For the trial, the team included 60 adults (aged 18-80 years). Spasticity and pain was significantly improved in the THC-CBD spray group compared with placebo. Overall, THC-CBD spray was well tolerated and adverse events were mild to moderate, the researchers said.