I tend to think of documentaries like Jonathan Caouette's Tarnation, Delaney Ruston's Unlisted, and Kathy Leichter's Here One Day as exorcism films. Not in the literal sense, but in the sense that the director, in making a film about a close relative's struggle with mental illness, brings it out of the darkness and into the light where they can attempt to make some sense of it and to move forward with their lives.

In more general terms, these films help to de-stigmatize something still considered a taboo subject in many families, which has always struck me as ironic since mental illness is so widespread—it doesn't discriminate on the basis of age, gender, race, or anything else, really. Bipolar disorder, for example, runs on both sides of my family, so it's something which I grew up with, and never really questioned. It wasn't a dirty secret (though we had those, too). I couldn't say for sure, but I believe it contributed to my maternal grandfather's suicide in the 1970s.

Elena, Petra Costa's multi-layered documentary, which opens this Friday at Grand Illusion Cinema, represents the means by which the first-time filmmaker came to terms with her older sister's life, legacy—and depression. Long after Elena moved to New York to pursue a film career, their mother, Li An, encouraged Petra to stay in Brazil and to do anything other than act, but Petra would move to Manhattan in 2003 to study theater at Columbia.

Petra had an ulterior motive in moving to Manhattan: to retrace the steps that led to her sister's irreconcilable depression and, though it goes unstated, to make a film about that trajectory. She combines Super 8 scenes of the city with home video, montages, English-language voice-over (in the US version), and excerpts from the audiotapes Elena sent to her, turning the film into a dual-narrative effort.

Though Li An didn't pursue acting, due to limited opportunities in the 1960s, she passed that ambition on to her firstborn. Instead, she and her husband became communist revolutionaries. Petra cites her pregnancy with Elena as the reason the military didn't execute the couple for protesting against the government.

As a girl, Elena became interested in filming and being filmed. She received a camcorder for her 13th birthday, and her video footage makes this a more fully realized feature, much like the footage that brings Capturing the Friedmans to life. At 17, she left home to act, first in São Paulo and then in New York.

In the US, she took lessons in voice and dance, but roles were scarce. Petra and Li An, who had since divorced, joined Elena in New York just as depression was starting to burn her up from the inside. The sad irony is that her tapes reveal a woman who had a way with words, making it seem as if she missed her true calling: as a writer.

Petra ends by examining what happened next, which I won't spoil here, but that's when the larger picture came into focus. Elena doesn't simply profile a woman who became depressed because she was stranded in a strange land or because her career failed to live up to her expectations—though those factors didn't help—but a woman whowas just depressed. It can happen to anybody at any time. After all, she had friends and relatives who loved her. She wasn't alone. But she felt that way.

I'd imagine this is old news for some people, but Petra finds a more eloquent way to make it than most, i.e there's no speechifying, no statistics, no excerpts from the DSM-5. Granted, the accumulation of "arty" imagery can be overwhelming—lots of blurred-out closeups of leaves and water and such—but what the hell. She's just telling the story of one woman who happened to be her sister; a sister who was like her in nearly every way. Petra looks like Elena, she shares her interests, and, given time, she could end up battling the same demons. But at least she has a better idea of what she's up against. Elena blazed a trail she didn't even know she was on, but it lives on in this film.