Different strains for different gains, some can boost creativity while others will straight up lay you on the couch!

More research is needed, but I've read a load of papers suggesting it actually does boost more than depress (years ago in college). A bit off topic but check out the Stoned Ape Theory:

It suggests other (organics) that may have assisted human brain development for thousands of years. Worth the thought.

Cheers !BEER