There's a whole host of reasons why drug trials fail, be it in animal testing phase or not.
The role of preclinical animal tests is to check if the drug offers any potential therapeutic value and if it is safe enough to move to Phase 1 trials in humans.
So why is there so much value placed on animal testing if we cannot draw links between the two?
Anyways to get back on track, here is more evidence to suggest the pot is a gateway drug:
More than eight in ten (84.4%) of those who had used any illicit drug in the last year had used cannabis in that time.
Three quarters (75.1%) of those who had used any drugs in the last month reported cannabis as the drug they had taken most often in that period.
Polydrug use / mixing alcohol and drugs among recent users
Almost a third (32.7%) of adults who had used at least one illicit drug in the last month reported some kind of polydrug use involving that drug ever.
Over six in ten (63.6%) of those who had ever mixed the drug they used most often in the last month with any other drug, had mixed other drugs with cannabis, reflecting the predominance of that drug as the drug used most often
Late teens (16-19 years) was the most common age for first using drugs, with over half (52.0%) of adults who had ever used drugs reporting having first tried illicit drugs at this age. A quarter (25.2%) of those who had ever used drugs first tried them when they were less than 16 years of age.
Reflecting its dominance, cannabis was the first drug tried by more than three quarters (78.3%) of those who had ever used any illicit drug.
More than eight in ten (84.4%) of those who had used any illicit drug in the last year had used cannabis in that time;
Almost one in five (19.4%) of those who had used at least one illicit drug in the last month said they felt dependent on or needed to take cannabis in that period;
http://www.scotland.gov.uk/Publications/2011
Stay away from it lads.
