Medical cannabis experts and advocates, Hannah Deacon and Professor Mike Barnes, sit down with their guests to find out why cannabis matters to them.---After studying biomedical science in Belfast, Ryan McCreanor worked as a toxicology scientist on one of the first commercially available testing kits for synthetic cannabis, which at the time was being sold as legal highs known as "Spice".After quitting his job for a stint of travelling he landed in Canada around the time of the legalisa...