Afterparty is a new, excellent science fiction novel by Daryl Gregory, about drugs, God, sanity, morals, and organized crime. Its protagonist, Lyda Rose is a disgraced neuroscientist who once helped develop a drug that rewired its users' brains so that they continuously hallucinated the presence of living, embodied Godhead. Now Lyda is in a mental institution, where she is attempting to win over the therapists who oversee her -- as well as the angelic doctor that manifests only in her mind.
It's a Phil Dickian setup, but the setting is a kind of mature next-wave cyberpunk world populated by wired-in spooks (who are also just plain wired on their own tailored neuro-dope); ruthless, dope-peddling microfinance gangsters; ecstatic religious cults subsisting on home-printed tailored God-dope; and an economic backdrop of stark rich/poor divides, all-powerful states, and paranoid ex-special-forces ninjas who fight the world and their own cracked minds.
Gregory is a great plotter, and the story races along like a thriller, but mountains more substance than your typical thriller. From existentialism to theology to neuroethics, Afterparty is part philosophy exercise, part science fiction novel.