The original paper has this quote: "But cocaine makes the housekeeper throw away really important things, like mitochondria, which produce energy for the cell."

- http://www.eurekalert.org/pub_releases/2016-01/jhm-nei011316...

I think that most stimulant users are emotionally disturbed. Cocaine users tend to be depressed, amphetamine users tend to be angry, but while 'high' they get to feel good (or 'normal'), at least for a while.