A Head Full of Ghosts by Paul Tremblay (2015)

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Terrifically spooky novel about a family that appears on a reality television show about their daughter's possession.

The story starts out with the younger sister of the afflicted girl telling her story to a journalist and remembering the events. What Tremblay does so well is capture the viewpoint of an 8-year-old girl who is genuinely unsure about what is happening in her house. 

Spooky and yet endearing; genuinely suspenseful and creepy.