I say that as someone who has been in several bands. I play very heavy music. I haven't overdosed. Just the fact that I work in a hospital keeps me away from illicit drugs since I am responsible for helping save lives when I work.
Additionally, I am, and have been for some time, a student of the sciences. Assume nothing without evidence.
I am not saying necessarily that it was not drug related. I just hate to see people rush to conclusions that musician = druggy. I view it the same way as the alarmists who say violent crime = video game influence.