Sad to hear, one of my fav actors of all time. But sadly, over the decades he has had drug and drinking problems, and previous sucide attempts.
It is rarely known that Carrdine was on a short list of actors to replace Nimoy as Spcok during TOS's second season, when GR was wrried that Nimoy was getting "too popular."
"High Priestesses Of Zardoz" By Eliza's Starbase Of Avatars Copyright 2009."
"Zardoz Speaks To You, His Choosen Trek Fans."