A British scientist is still hopeful that cannabis extracts will relieve the symptoms of multiple sclerosis (MS) patients - despite disappointing research results.
Testimonies from many MS patients suggest that the drug is helpful in relieving symptoms such as spasticity - a painful rigidity of muscles experienced by many.
However, a small Dutch study of only 16 MS patients given cannabis extract in capsule form found no apparent benefits.
He said: "This is one study among dozens being conducted into MS.
"I have many patients on my trials coming back saying cannabis has improved their quality of life."
The Dutch study, published in the journal Neurology, involved patients with severe spasticity.
They were given either a synthetic version of a cannabis chemical, or extracts of the plant itself.
Some were given a placebo - a capsule containing no active ingredient.
However, after four weeks of treatment, there was no discernable difference in the level of spasticity.
And when the patients were asked to rate their own progress, those on the active drug treatment actually believed they were worse off.
Dr Joep Killestein, who led the study, said the tiny number of patients involved meant that no firm conclusions could be drawn.
He also offered some explanations as to the lack of effect.
He said: "One could be the way that the drug was given in a capsule."
He also said the relatively low doses might also be to blame.
Dr Nottcutt told BBC News Online: "We have been giving patients the drug through a nasal spray so we can get them up to the right dosage very quickly.
"We tend to work on the most difficult patients - and with these, it isn't always certain that the drugs will work."