Comedian Jim Norton has reflected on the life and tragic passing of Robin Williams, who he was fortunate enough to meet during his performing years; and Norton has given some insight into why many comedians struggle with depression and demons.

In the 25 years I’ve been doing stand-up, I’ve personally known at least eight comedians who committed suicide.

By all accounts, Robin struggled with depression and addiction over the years. So many comics I know seem to struggle with the demons of self-hatred and self-destruction. While my physically self-destructive days ended when I got sober, the thought of suicide was always there, an option behind glass that I could break in case of an emergency. I glamorized the idea of constructing my own exit.

Norton goes on to say that stand-up comedy has changed significantly throughout the years, and the material used in the modern era tackles the tough emotions that many of the comedians are hiding.

The funniest people I know seem to be the ones surrounded by darkness. And that’s probably why they’re the funniest. The deeper the pit, the more humor you need to dig yourself out of it

Over the years, comedy has gone from happy-go-lucky pie-in-the-face jesters to the stuff of the deeply personal and honest with the coming of Lenny Bruce, Richard Pryor and George Carlin. The public began to see, through brilliant material and public battles with personal demons, that the people who made them laugh the hardest seemed to be enjoying life the least. Maybe all those jokes were hiding something much darker. The cracks in the exterior began to show.

Check out the full story on TIME.