A Mind Full of Scorpions by J R Billingsley

A young boy, kidnapped, only to be returned, talking of aliens. A witch destroys a cult and a coven in a quest for ultimate power. A witchdoctor unleashes zombies on a planned neighborhood in Miami. A mysterious unnamed man in a suit may be more than he seems. A murdered Chicago detective needs help discovering who killed him. 
 
In A Mind Full of Scorpions, book one of the Eyes-Only trilogy, former FBI agent Adam Richardson has had his mind broken after a violent end to a haunting case. Diagnosed paranoid schizophrenic, Adam moves back home to Northwest Arkansas under the care of his younger brother. As Adam settles in, he begins to suspect that some of the things he sees are real. Like the Shimmers, the princes of Hell who embody the seven deadly sins. When Adam’s former partner comes asking for assistance hunting down the paranormal, a new danger rears its head. Now Adam must find a way to stop the forces aligning against him and his friends as he struggles to quiet the voices in his head once and for all.