Flutterby™! : Cannabis might keep you smarter...

Futurism: Research Suggests the Older You Get, the More Weed You Should Smoke

In experiments using human brain cell cultures and animal cells, the researchers found that cannabinol appeared to protect neurons against oxidative stress, a pernicious form of biological wear and tear that leads to cell death. Oxidative stress is considered a critical factor in neurodegenerative diseases like Alzheimer’s.

Salk Institute: Active ingredient in cannabis protects aging brain cells

Salk researchers find cannabinol preserves mitochondrial function and prevents oxidative damage to cells

I'm gonna say edibles are probably better than smoking, but...