David nutt is brilliant. I loved his book drink. However I think that horse riding Vs mdma point is a bit limited. I think there are dangers worth facing as the overall experience probably helps you grow as person, so horse riding has the dangers, the skills, the discipline and the responsibilities that go with it. In my mdma taking years I don't think I met anyone who benefited from it. In fact I know of quite the opposite.

Edit: btw I think all drugs should be decriminalised.