Sir, Mrs Lezley Gibson (letter, February 17) notes how cannabis
prevents her from being severely disabled by multiple sclerosis.

A major trial with cannabis is about to start in the South West of
England to establish the extent to which cannabis helps those with
this distressing condition. It may be hoped that the drug will be
available on prescription if good scientific evidence shows that
cannabis can have a worthwhile effect.

Research in this field is difficult since the manifestations of
multiple sclerosis are so variable and the clinical course so erratic.
It is difficult, if not impossible, to show the value of medication in
the individual patient, although studies in groups of patients can
produce worthwhile results.

Yours sincerely, C. Gardner-Thorpe (Consultant neurologist), The
Coach House, 1a College Road, Exeter, Devon EX1 1TE.