"Are you out of your mind?" the wife asks the husband.

A throwaway line in an average conversation, perhaps, but in the context of Jeff Nichols' melancholy and deeply affecting "Take Shelter," the question takes on a much more ominous meaning. The dread in this slow simmer of a film comes not from a clearly definable sense of danger, but more from a sense of simply not knowing.

Is it a commentary on global warming? Our nation's festering economic woes? The trauma of mental illness? For a member of the audience, the suspense is troubling enough. For the main character, it's agony. The impact of the film rests in how effectively it insinuates us into that character's mind – and finds the humanity in the midst of the terror.

It plays today only at the Tower Theatre as a Fresno Filmworks presentation.

Curtis, played with a harrowing and finely etched sense of malaise by Michael Shannon, is the husband. He has a conventional life in a small Ohio town: solid blue-collar job, good friends and drinking buddies, comfortable if not extravagant house, a loyal dog. His wife, Samantha (the hardscrabble and finely wrought Jessica Chastain, also wonderfully cast), is supportive and loving. They both dote on their only child, a young, hearing-impaired daughter.

But Curtis starts having dreams. Each one is punctuated by terrible storms, the kind that send unheard of swirls of menacing clouds into the sky. Lightning crashes, birds freak out, a viscous liquid rains upon the Earth. Worse yet, people in Curtis' dreams do bad things to him. Even his dog turns on him, biting his arm.

Perhaps most ominously, Curtis' arm hurts even after he wakes up.

And from there, he becomes convinced he needs to build a storm shelter in his backyard. Is he deteriorating into paranoia? Or have an inside track on a coming calamity?

"Take Shelter" is buoyed by a phenomenal performance from the Oscar-nominated Shannon. The craggy, mystified landscape of his face darkens as much as the storms he sees in his dreams.

Nichols' direction is scrupulously nonsentimental, a key ingredient in the film's success, and while Nichols isn't immune to using standard suspense-driven movie conventions – including a couple of fine gotcha moments – there's a rigid discipline to the film that relies much more on psychological impact than cinematic tricks.

Ambiguity is important here, of course, which is why I don't want to dive into the film's more complex plot-related waters. But it's clear that most audiences will want to anchor this movie to gloomy times. Even when an individual feels able to mostly deal with life's challenges – just like Curtis does at the beginning of the film – there is a strong narrative at work today that as a society, things are crumbling. Whether it's climate change or economic woes, will our worst dreams materialize?

To paraphrase: Are we going out of our minds?