http://www.nytimes.com/roomfordebate/2016/04/26/is-marijuana-a-gateway-drug/marijuana-has-proven-to-be-a-gateway-drug

Ok, last time....

This is your brain.

This is drugs.

This is your brain on drugs.

Any questions ?

https://www.youtube.com/watch?v=ub_a2t0ZfTs