Razorback update

I want my story to be readable by people of all ages, but there is substance abuse in the text, which immediately makes it unsuitable for a younger audience. I've tried to think of some way of presenting drug use in the story without exactly presenting it as such, but so far am struggling to come up with anything ambiguous enough. In Star Trek there was an episode in which a character used an implant in his head to release endorphins into his brain, but I'm not sure that would work as a "drug replacement" in my story.
What happens in the story is that one of my characters, Amber, gets caught up with a rough crowd and takes substances that alter her physically and mentally, enabling her to communicate with non-corporeal beings (whom she believes are angels, although they turn out to be far from benevolent). This is a fairly important development as far as that character is concerned, and not one that I feel able to write out of the text at this stage. One solution that has occurred to me is that Amber has undergone a bonding ritual with one of her new friends which involves an exchange of blood, and that addition of alien blood to her body causes the physical and mental changes that she experiences.
This idea is not unrelated to a development in the character of Amber's friend, Glinzel, who I see as a sort of charming, hedonistic cult leader/rock star type, a sort of cross between Jimmy Swaggart, Edward Cullen and David Bowie. My physical description of the character portrays a tall, slender young man with long silver hair and intricate swirling patterns drawn onto his chest and back. It has occurred to me that Glinzel is not exactly an alien, but a hybrid of human and angel - a Nephilim - whose ancestors escaped from Earth centuries ago and set up their own civilisation on a distant planet. This would explain why Amber's exposure to Glinzel's blood has the effect that it has.