Fear follows everywhere in teen horror film

One measure of a good horror movie is not how often you jump when the monster bangs out from behind a door, but how often you find yourself nervously peering at dark corners of the screen.

It only takes a few minutes of John Carpenter’s “Halloween” or Kiyoshi Kurosawa’s “Pulse” to make you dread what might be lurking in every unlighted nook or out-of-focus background. It’s been a while since a movie made me feel that way, but David Robert Mitchell’s “It Follows” creates that kind of constant anxiety.

Even the startling opening shot — a 360-degree pan around a normal suburban street, with no monsters in sight — instills the idea that something might be there, threatening, even if we can’t see it at the moment.

The premise itself is simple, if faintly absurd. A teenager, Jay (Maika Monroe, excellent in “The Guest”), sleeps with her handsome new crush; he then informs her that she is now the target of a relentless, shape-shifting ghoul, which will pursue her to death.

Her only escape is to have sex with someone else, who will then become the target. A few wrinkles provide extra horror: Nobody else can see the approaching monster, which could look like a normal person, even someone you know.

Also, these things move slowly, and they never stop. A slow-moving monster is more chilling than it might sound, but then most of our demons — the psychological kind, anyway — are slow but steady.

Still a young filmmaker, the Michigan-bred Mitchell (this film and his previous “Myth of the American Sleepover” were shot around Detroit) is already canny about using the camera to evoke mystery. Every time someone drifts into the background of a shot, we have to wonder: Is that just a random passerby, or is that, you know, “It”?

There’s also a wild musical score by Disasterpeace, which gives an aggressive — at times maybe too aggressive — accompaniment to the film’s eerie mood.

If the use of teen sex as a horror convention seems tired, rest assured that Mitchell seems less interested in a morality play than in sketching the in-between world of suburban adolescence — the way Jay and nerd-friend Paul (Keir Gilchrist) recall a childhood kiss, or the oddly sad presence of a portable swimming pool in the backyard.

It’s also an inspired touch that, although Jay’s friends share a warm, tribal bond, there are virtually no parents around (although a couple of instances of parental manifestation are horrifying). Parents have little place in the hothouse world of teenage melodrama — supernatural or otherwise.

“It Follows” (three and a half stars)

A fine update on the teen horror film, as our heroine (Maika Monroe) tries to dispel a mysterious curse that causes a shape-shifting ghoul to follow her around. Some real mystery in the low-budget atmosphere of David Robert Mitchell’s Michigan-based movie.

Rating: R, for violence, nudity, language

Showing: SIFF Cinema-Egyptian