David J Nutt, Leslie A King, Lawrence D Phillips, Drug harms in the UK: a multicriteria decision analysis, The Lancet, 2010.

https://bigfatgenius.com/2220%20Fall%202010/Nutt%20King%20Ph...

Cocaine (in crack form) was found to be the third most harmful recreational drug overall, after alcohol and heroin. It also caused the most direct harm to users out of all drugs. Cannabis, not so much, mid-table. Non-crack cocaine was somewhere between the two.

Note that this study is now over 15 years old.