ABANDONED. Adult Sci-Fi/ Fantasy/ Thriller. Machine found in old asylum being remodelled. Read around 2018. Spoilers ahead.

[RikuRoxas]

SPOILERS AHEAD




I read a book around 2018, it was about a guy getting a job in an asylum that was having one wing remodelled. He found a machine in a hidden room and thought it was used to either contact or create ghosts, but came to realise it was actually to cause symptoms of schizophrenia. There was also a lift found in the room to an office.
Really can't remember much more but I really enjoyed it at the time and can remember the author was on a shelf in a bookstore that's since closed around Lee Child, so I assume it's a C or Ch surname. I donated the book to a charity curbside collection so can't just go looking.
Book seemed relatively new at the time (2018/19) and the cover was, as far as I can remember, water with an island and yellow text.

Thanks in advance for any help, it's driving me insane.

[Kris]

PupRiku, what is the man's job at the asylum? Who hires him?

What is the story's time period and location?

[Kris]

RikuRoxas (OP) left the group. Moving to Abandoned folder.