I think this film's getting a little more credit than it deserves. There's a sense in which the threat in it is a metaphor for PTSD, but there's also a very straightforward "It Follows"/"The Ring" rip-off going on, and these two elements directly clash. The film spends a lot of time on things that ultimately have no impact on the plot, so it goes into the climax having not really mapped out the nature of the threat. It's unclear what it is or what would defeat it, and elements of both ideas crash into each other resulting in a fairly incoherent conclusion that seems to suggest that childhood trauma is completely insurmountable.
It's not a bad film. The horror sequences are mostly well-constructed and the atmosphere of creeping doubt is compelling. But, oddly enough, the central hook that the film is named for is one of those elements that is ultimately irrelevant.
It's not a bad film. The horror sequences are mostly well-constructed and the atmosphere of creeping doubt is compelling. But, oddly enough, the central hook that the film is named for is one of those elements that is ultimately irrelevant.