This topic is back in the news – go to www.sciencedaily.com/releases/2014/05/140512155025.htm …. but it doesn't really tell us anything that wasn't known before. Drugs and alcohol appear to have had a non-recreational role associated with funerary rites – and activities that come under the umbrella term, ritual. Various bits on the subject have been published by SIS over the years, largely conjectural but suggesting ancient people were recreating a state of mind associated with whatever it was they were commemorating – in this instance, from an SIS perspective, a catastrophic event that may have produced ionisation in the lower atmosphere. Several books have been written on the subject, notably by Paul Devereux.