A warning appears on the screen before “A Mouthful of Air” begins, suggesting it might be “upsetting for for people with depression and anxiety.”

And it’s not uncalled for. There’s a disquiet to the film and Amanda Seyfried‘s unsettling performance as the lead, a woman suffering from dangerously destructive anxiety and postpartum depression after the birth of her little boy, Teddy.

Seyfried filmed the movie in between the births of her two children, and looks gaunt and drawn for much of “A Mouthful.” Her character, Julie “Jules” Davis may have a work-at-home career, writing and illustrating children’s books (animated at times in the film). She may dote on her unfussy, smiling baby — over-decorating his room, reading and talking to him incessantly, bathing and walking and playing with him and taking him all in with those big adoring eyes.

But the eyes give away Jules’ unease. She’s weeping. Is it over gratitude and joy at having a perfect child in a loving marriage (Finn Wittrock plays her husband)? She constantly leans on and snuggles with husband Ethan. Is she being unduly clingy? He’s guarded around her. What does he know? What does he suspect? She sees it.

“I just don’t know what you’re trying to find.”

“You!”

Writer-director Amy Kopelman, adapting her novel (as she did on “I Smile Back”) uses the sad but hopeful stories of Jules’ “Pinky” character — either read by Jules or animated — flashbacks and cinematic flash-forwards (hinting at what’s to come) in telling this story.

We meet Jules’ earthy, sympathetic and nurturing Mom (a luminous Amy Irving). We hear about the “mentally ill” father who’s no longer in the picture.

And we meet Jules’ psychotherapist (Paul Giamatti).

Because we’ve seen her creating art for the books, Teddy’s room and the elaborate decorations she plans for a bookstore reading. But that precision knife she’s picked up isn’t just for cutting out paper shapes. We’ve seen flashes of an ambulance, her sister-in-law’s (Jennifer Carpenter) bloodstained sweater and the way even their building’s maintenance man (John Herrera) looks at Jules with concern.

She tried to kill herself.

Kopelman never over-explains Jules or her illness, although she does make a modest attempt at “cause and effect.” Characters like Ethan are sketched in, fleshed out gradually, their personas shaped by concern for Jules and fears of her mothering/smothering instincts.

When she over-decorates for a one-year-old’s birthday party and reassures her spouse with “We made it to ‘one!'” that’s kind of a cause for concern.

Her OB-GYN (Josh Hamilton) confesses to now “asking (new) mothers how they’re doing…because of you.”

Her blunt but soft-spoken shrink is all words of warning — “If you fall into a pool and you don’t know how to swim, you drown.”

Her husband quietly fumes “I’m not ALLOWED to get mad at you.”

And her sister-in-law cannot control her “not helpful” fury and judgement over what Jules is going through, because there’s a baby in jeopardy every day Mommy doesn’t take her meds.

“A Mouthful of Air” is a film of disquieting nervousness, our concern about what’s to come — either for Jules or her baby or both.

Seyfried is better at overdoing the “loving mother/loving wife” bit, giving us a sense of the facade Jules knows she must maintain. The thousand-yard-stare of a woman who feels inadequate, lost and damaged is meant to carry the picture, and it doesn’t. Not really.

But it does a good enough job of giving us a helpless outsider-looking-in view of this foundering form of postpartum depression, making us sympathize if never quite helping us understand how this happened to Jules and what those who love her can do — beyond chemicals — to save her.

Rating: R for some language (suicide subject matter)

Cast: Amanda Seyfried, Finn Wittrock, Amy Irving, Jennifer Carpenter and Paul Giamatti

Credits: Scripted and directed by Amy Koppelman, based on her novel. A Sony Pictures Classic release.

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