“I know I’m unique,” announces Billy, an opinionated 10th grader and the willing subject of Jennifer Venditti’s sly documentary, “Billy the Kid.” Delivered almost apologetically, the comment is without arrogance. But as one candid confession follows another, the camera’s role in their solicitation becomes difficult to overlook.

Filming for eight days during the summer and winter of 2005, Ms. Venditti follows Billy as he navigates his close-knit community, Lisbon Falls, Me. A seemingly normal teenager who likes girls (“but I’m not a jerk about it”) and loves heavy metal, Billy also struggles with a volatile temper and the disconcerting tendency to say exactly what he means. Both traits have isolated him from his peers, inflamed the local bullies and driven him more deeply into a mind that may or may not conceal more serious psychological problems.

Presenting neither an argument for medication nor its rejection, “Billy the Kid” is a deceptively simple portrait of a shockingly self-aware and articulate young man. Quoting Robert Frost as easily as “The Terminator,” Billy discusses his troubled past (“I don’t know where to start”) and his deep-rooted desire to protect women. This is evident in the tender, patient interactions between the boy and his mother, Penny, which provide the film with a much-needed core of stability and an antidote to Billy’s free-form observations.

Yet the filmmaker’s decision to eschew other viewpoints underscores the fundamental friction at the heart of the documentary process: the flattery of observation is difficult to resist. When Billy, after persuading a shy waitress to be his girlfriend, is loudly applauded by a clique of town hangabouts, he is pleasantly surprised.

“The years of loneliness have been murder,” he tells them, and the men collapse with laughter. Whether a blurted confession or a line to the gallery, we’ll never know.

BILLY THE KID

Opens today in Manhattan.

Directed by Jennifer Venditti; director of photography, Donald Cumming; edited by Michael Levine; music by Christian Zucconi and Guy Blakeslee; produced by Ms. Venditti and Chiemi Karasawa; released by Elephant Eye Films. At the IFC Center, 323 Avenue of the Americas, at Third Street, Greenwich Village. Running time: 1 hour 24 minutes. This film is not rated.