If you look at who generally dies from drug overdoses it's largely opiate-based drug users. I once listened to two junkies who hadn't seen each other for quite a while talking and letting each other know about who died. They were mostly talking about overdoses, the conversation went on for about 30 minutes non-stop with different names non-stop. None of the cokeheads, eckyheads (MDMA), or speed freaks I knew ever had conversations like that.