He calls it experimenting. What would you call my boyfriend's drug use?

[Evolution]

Ive been dating this guy for a while now...when I met him he was only an occasional smoker, and drinker. Which was ok since I have the same habits. But lately hes been really into trying new stuff. The experimenting part isnt whats upsetting me though...Ive tried to talk to him about it but when I do its like he thinks Im speaking another language...He seems to be driving at a really high speed with this whole experimenting thing...he isnt just trying one thing new at a time...hes doing things in combination...and he is getting completely fucked out of his mind everytime he does it. It seems completely destructive to me...Im fine with trying things but I think drugs are being used wrongly if you are getting smashed eveytime you use them. He hasnt done anything physically addictive yet but his usage is escalating and at an alarming rate. Is there a reason why he may be doing this? And what should I do? I dont think I can be in a relationship with him if this goes much further....has anyone else had any similar problems in a relationship? I would love to hear from a guy who has been told the same thing by his girlfriend to...it would help to hear from both sides