Luke Flanagan (Roscommon-South Leitrim, Independent) | Oireachtas source

The brain damage argument is based on what is termed the Dr. Heath/Tulane study. As part of this study, rhesus monkeys were strapped into chairs, had gas masks placed over their faces and were given the equivalent of 63 Colombian-strength joints in five minutes, losing no smoke. That one always gets a laugh. After smoking this cannabis, the monkeys ended up with brain damage. What the study remarkably ignores is that the monkeys' brains were in fact damaged by oxygen deprivation and not by cannabis.

See this speech in context