Films about the sex, drugs and rock ‘n’ roll experiences of pop performers seem to be developing into a tidy little cinema niche of its own: their failures, successes and excesses; the abuses of substances; the perks and perils of celebrity or obscurity; the public lives lived in a fishbowl, the often spectacular, often young, deaths. In The Devil and Daniel Johnston, music documentarian and film commercial director Jeff Feuerzeig tackles the equally sad spectacle of the artist still alive but descending into a private world of the delusional manic-depressive.

Therapeutic drug-bloated and –aged beyond his actual forty-something, and well known among followers of the underground in music and in comic book-inspired art, the subject introduces himself as “the ghost of Daniel Johnston, [who] many years ago lived in Austin, Texas, and worked at McDonald’s.” Back a quarter of a century, Austin, Seattle and even a sector of Los Angeles were developing as centers of so-called alternative music, and this youngest of five children of a demanding but ultimately sympathetic and supportive New Cumberland, West Virginia, Church of Christ family wound up in the Lone Star capital via a circuitous route. His road had gone through religious and other colleges, living with much older siblings, and carnival work as a runaway. For a long time he had been playing, recording and illustrating his own music and, handing out his rough “Hi, How Are You” cassette tape of “twenty or more amazing songs” while clearing off fast-food tables at Dobie Mall, became enough of a local celebrity to wangle a 1985 spot appearance on MTV.

Not so-suppressed inner monsters surfaced, however, maybe partly unchained by some drug use and one controversial experiment with LSD, and the life since then has been an alternating succession of rare public performances and not-so-rare public breakdowns, institutionalizations and home care with his elderly parents in Waller, Texas, and promotion and lionization in some quarters -- Kurt Cobain, Matt Groening and David Bowie -- with the accretion of a weird legend beyond what may not be one-hundred-percent facts.

Director Jonathan Caouette pared down twenty years’ worth of video and other varied-media material from a reported hundred-sixty to one-and-a-half hours for Tarnation, but remained too close to that intimate record of family dysfunction to edit it into distanced cinema art. In the present case, on the contrary, Feuerzeig has done a creditable job in organizing his own collection of material, the contributed recollections of many whose lives Johnston affected, and the massive, colossally self-celebratory, increasingly whiney and something like born-again fundamentalist, aural and visual record kept by this very troubled mix of fame-seeking bravado and petrified stage fright.

Unified, too, by an occasionally unlifelike Super-16mm format, the film includes footage of recent concerts and a strange Stockholm sing-along but in the end is not so much about music per se, as about the fearfully thin line separating man from madness or, in Johnston’s vision, from Satan. The bands with in-your-face names, the artists and commentators from this fringe “underground” world will seem to most viewers immature and narcissistic, but the problems facing Johnston and his elderly parents Mabel and Bill are the stuff of life’s tragedy.

Therapists surely have had their input regarding this “eye guy's” compulsive drawings of devils and amphibians with multiple prominent eyeballs set onto antenna-like appendages. Coincidentally but suspiciously reminiscent of Petrarch’s unidentified Avignon Laura who launched a thousand European love lyrics, virgin Johnston’s exaggerated thematic wail of rejection by Laurie Allen -- who deliciously married an undertaker surnamed Archer -- also beckons to armchair Freuds.

The singer’s adenoidal adolescent renderings of his compositions as commentary, his more recent public appearances freak shows more than performance, his greyed hair and sudden girth a testament to treatment and drugs, all fade into background. The impression that lingers with the viewer if not the man is of his pathetic absence of real self and of dignity, and the dedication of others. Particularly touching are the loyalty of his shabbily treated former manager Jeff Tartakov and the caring of his octogenarian parents, put-upon early and long but always accepting and now his loving, worried refuge.

(Released by Sony Pictures Classics and rated “PG-13” for thematic elements, drug content, and language including a sexual reference.)