Swallow is a great movie about mental illness, but it's not your typical mental health story. It deals with pica, a compulsive behavior in which the afflicted eats objects that are not food. That might seem unconscionable on the surface. In reality, the compulsion is, in part, about obtaining control when a person feels they don't have it. They may feel other things in their life are chaotic, so deciding what to eat – and knowing that no one else is in on the secret – provides the emotional satisfaction of being in control. Writer/director Carlo Mirabella-Davis crafts a compelling story around that idea, helping us understand what would pull someone in such a dangerous direction.

Haley Bennett plays Hunter, the pregnant trophy wife of wealthy hot-shot businessman Richard (Austin Stowell). We can tell right away that he loves her primarily because she lives to make him happy and projects the right image. A sense of her misery is palpable, though. While Richard works for his image-conscious father Michael (David Rasche), Hunter socializes with his mother Katherine (Elizabeth Marvel). She's one of those people who seemingly pretends to be compassionate because it's the socially acceptable thing to do. Genuine warmth doesn't exactly radiate off her.

Surrounded by these artificial people, Hunter is utterly stressed. Already prone to doing things like chewing ice cubes, she one day picks up a marble, swallows it, then retrieves it after it comes out the other end. Then she swallows a thumbtack, a AA battery, and so on. Her compulsion to eat various objects grows. Richard and his parents find out, and their grave concern is based more on how it affects them than on Hunter's mental well-being.

Swallow spends the first hour detailing how the character falls deeper into the spiral of pica. With a husband and in-laws who make virtually every choice for her, it's easy to see the pull of doing something they can't control. Haley Bennett is superb, making clear Hunter's motivations without the need for any dialogue explicitly spelling them out. The actress captures the mixture of heartbreak, dissatisfaction, and yearning to find herself that fuels the compulsion of the woman she's portraying. Most shockingly – and this is entirely appropriate – Bennett additionally conveys the little thrill Hunter gets with every item she puts into herself.

The final half-hour takes everything we've witnessed down a different road, one that gets at the heart of what it requires to cope with mental illness. Hunter has something in her past that she's avoided dealing with. Swallow accurately shows how processing emotions is a major part of treatment. Compulsive behaviors begin as a means of alleviating anxiety; coming to terms with the root causes of that anxiety typically brings a level of relief. That the film has clearly been so thoroughly researched makes it special. This isn't a story of “movie mental illness,” it's a work that contains significant authenticity.

Swallow is also a powerful story about a woman in need. Skillful production design and the use (or absence) of certain colors makes Hunter and Richard's home feel icy and detached, which in turn helps Hunter's situation register even more strongly. Mirabella-Davis ends with a long, static shot that provokes us to wonder how many other women out there are in the same place – forced into roles they don't want by people who are only really interested in themselves, or suffering from mental illness silently. Swallow sends them recognition and love.

With Haley Bennett's outstanding work at the center, the film is a true stunner.

out of four

Swallow is rated R for language, some sexuality and disturbing behavior. The running time is 1 hour and 36 minutes.