It’s not often that one witnesses an act of fearless self-revelation on screen, but that’s what Jonathan Caouette’s “Tarnation” amounts to. The non-fiction film, compiled on a computer from a cache of home movies at a cost–the filmmaker tells us–of $218.32, is like a cinematic psychiatric session in which Caouette investigates his own dark, disturbing past, as much, one supposes, to exorcize his own demons as to tell us about them. With its fly-on-the-wall approach and heavily experimental visual style, the result can be both enlightening and creepy in almost equal measure, but it’s more than a stunt: it’s a cry of anguish you’re not likely to forget.

The fascination of “Tarnation” lies in the facts of Caouette’s life. He was born in Houston; his mother Renee was a child beauty whose injury in a fall briefly paralyzed her and led to her receiving shock treatment for a suspected mental disorder. But rather than helping, the therapy seems to have encouraged the development of full-blown schizophrenia. His father wasn’t in the picture at all, having abandoned his family very early on. The result was that Renee and her son were largely cared for by her parents Adolph and Rosemary, who on the evidence presented here were hopelessly out of their depth; and matters worsened when Renee went off to Chicago with Jonathan, where she was raped in view of the young boy. On their return to Texas Renee was repeatedly hospitalized and institutionalized, while Jonathan spent time in a succession of foster homes–in some of which he was abused–before being adopted by his grandparents. It was during his years with them that he not only recognized his attraction to the city’s gay subculture but began–as early as age eleven–using cameras and tape recorders to document and examine his life, as well as give rein to his inclination to drama (in one memorable excerpt, the young boy is shown portraying what might be a battered Tennessee Williams heroine) . Eventually he moved to New York City and found happiness with a partner, David; but his connections to his past were never severed, and a good deal of “Tarnation” is devoted to his coming to terms with his family, not only his mother and his now-widowed grandfather, but also his long-absent father, who, in an especially memorable scene, visits him and Renee in the New York apartment Jonathan shares with David.

What made “Tarnation” possible, of course, was the wealth of material Caouette made and saved over the years–not only videotapes and still photos but interviews and found footage to provide context. But what makes the film compelling is the imaginative, frankly obsessive fashion in which he’s pulled all of it together. He arranges the elements to create a sense of mystery about the outcome, beginning with almost claustrophobic footage of him reacting to news of his mother’s latest hospitalization and proceeding to dole out information in drips and drabs rather than a conventional, quasi-objective “narrative.” He also uses the techniques of more experimental films–breathless montages and overlays, sound and image manipulation, whiplash editing and quick pop culture insertions–to create a mood of cinematic desperation and confusion that mirrors those facets of the autobiography itself. The result is a truly devastating portrait of the effects of mental illness and social dislocation, the form of which complements the content.

“Tarnation” is, of course, a very personal project, one which must have cut very deeply to the bone for the filmmaker himself. That sort of effort might have been so insular that outsiders couldn’t connect with it. But in this case by exposing his own nerve endings, as it were, Caouette touches ours as well. “Tarnation” isn’t easy or comfortable to watch, but its potency makes it well worth investigating.