'Infinitely Polar Bear' (R)

A shaky-cam indie movie that starts with home-movie footage and a child’s voice-over? Are you kidding me? Maya Forbes’ Boston-set Infinitely Polar Bear (the title is a play on the word “bipolar”) begins in the 1970s with the voice of Faith Stuart (Ashley Aufderheide), mixed-race, younger sister of Amelia Stuart (Imogene Wolodarsky), and daughter of manic-depressive scion of famous Boston family Cameron Stuart (Mark Ruffalo) and mother Maggie (Zoe Saldana), a smart and beautiful black woman from the Midwest.

What we are about to see is the timely coming-of-age tale of two girls, though perhaps oddly focused on their parents’ struggle to stay together despite Cam’s mental illness and long separations caused by Maggie’s desire to complete her business degree at New York City’s Columbia University. Maggie wants to make herself capable of making a living and keeping the family afloat because she cannot rely on Cam. Although Cam’s family is rich, his great-grandmother Gaga (Muriel Gould), who holds the proverbial purse strings, will only pay for a rent-controlled city apartment for the family.

Admittedly, the Stuarts have more than one non-earner in their storied clan. Cam’s Gaga condescendingly refers to Maggie as a “striver,” as if trying to improve your and your family’s prospects is a quaint notion.

Cam, who is never without a lit Lucky Strike, is a fairly typical character of this kind. Thrown out of Exeter and Harvard, Cam has culinary and mechanical skills and keeps a vintage aquamarine Citroen DS Wagon going. He was a lighting designer for WGBH. But he lost his job after a fight with his boss and suffers a nervous breakdown, landing him in a psych ward. When he emerges, Maggie decides to finish her degree, reluctantly leaving the girls in her troubled husband’s care, vowing to come home every weekend. Cam argues that he does not want to be “the wife” and tries to medicate himself with beer instead of the debilitating, psychiatric medication.

In large part, the film is about the girls’ “adventure,” learning to deal with their father’s eccentric, at times insane behavior, and these scenes are the film’s most interesting and memorable. The young performers are very good as the alternately frightened and angry Faith and Amelia. Ruffalo and Saldana also have a wonderful chemistry.

The film was shot in Providence, but the Boston touches are nice: They include a reference to a family mansion on Beacon Hill designed by Charles Bulfinch and a Stuart portrait by John Singer Sargent in the Museum of Fine Arts. Presumably, that would be the portrait of Charles Stuart Forbes. But the film is overall too generic, and the shaky-cam stylings of cinematographer Bobby Bukowski, which call attention to themselves, are an outdated annoyance.

Cast: Mark Ruffalo, Zoe Saldana, Imogene Wolodarsky, Ashley Aufderheide, Beth Dixon, Keir Dullea.
Writer-director: Maya Forbes.
A Sony Pictures Classics release. Running time: 90 minutes. Vulgar language. In Miami-Dade: Sunset Place, South Beach, Aventura; in Broward: Gateway; in Palm Beach: Living Room, Shadowood.