Ask Carl Sagan!
Seriously though, various substances and activities can have totally different effects on our actions and thought processes. Find what works for YOU and don't be constrained by the biases and opinions of others .Been a fan of cannabis for over 40 years with no discernible negative outcomes, yet respect other's choice to not partake. To each his/her own.
As it pertains to poker, I like a small amount prior to starting a tourney to enhance my patience. Like most things in life, know your limits and practice moderation.