Darren Aronofsky, who used a wide variety of inventive camera tricks (many of them of film-school provenance) to generate a powerful mood of paranoia in his surprise-hit debut feature “Pi” (1998), adopts a similarly flashy approach to portray the downward spiral of drug use in his sophomore film. But while the repetitive montages devoted to the endless cycles of addiction certainly have stylistic flair, they don’t possess anywhere near the sense of spontaneity and sheer cinematic exuberance that the devices in the earlier picture had. “Requiem for a Dream” is an experiment which, unhappily, doesn’t quite come off, an all-too-predictable downer which isn’t salvaged by the director’s effortful razzmatazz.

The script derived by Hubert Selby, Jr., and Aronofsky from the former’s novel focuses on four doomed characters: Sara Goldfarb (Ellen Burstyn), an aging Brooklyn widow who obsessively watches what appears to be a cross between a game-show and a self-improvement infomercial on the television in her dingy flat near Coney Island; her dissolute son Harry (Jared Leto), who alternately uses drugs and tries to market them at a profit; Harry’s girlfriend Marion (Jennifer Connelly), who gets increasingly hooked; and his street buddy Tyrone (Marlon Wayans), who, like Harry himself, begins to consume the merchandise rather than selling it. The scenario is divided into seasons, over the course of which we follow the quartet’s irresisible descent into addiction and despair–Sara when, in response to a tentative invitation to appear on her favorite program, she goes on a crash diet that gets her hooked on pills prescribed by a quack, and the younger trio as they consume the drugs they’d purchased to push on the streets. The resultant plot arc may be authentic in terms of the awfulness of addiction, but dramatically it’s pretty obvious. The intent is doubtlessly to impart a feeling of inevitability and fatalism, to the characters’ plight, but even Aronofsky’s sharp cuts, weird juxtapositions, abrupt noises, speeded-up shots and oddball camera angles can’t sustain interest in a narrative that seems predetermined and foreordained; after its schematic setup, the film, like its characters, has nowhere to go but down. “Requiem for a Dream” is meant to have a hallucinatory, mesmerizing quality, but it manages to be about as enlightening as a bad acid trip.

That doesn’t mean, however, that the performances aren’t solid. Leto, Connelly and Wayans are all impressive if inevitably one-note, and it’s nice to see Louise Lasser again as Sara’s friend and seamstress. Christopher McDonald is successfully grating as the host of the TV show that Sara watches so intently–so grating, in fact, that it’s rather hard to believe that anyone would tune the thing in twice. The best (human) acting, however, is undoubtedly done by Burstyn, who has her finest role in years as the pathetic, needy Sara and invests her with considerable poignancy. Even she, though, is overshadowed by a mechanical performer–the grumpy, antagonistic refrigerator in her apartment that rumbles and squawks at its deteriorating owner. A machine hasn’t had such a showy, memorable part since that nasty slot machine seduced poor Everett Sloane in the old “Twilight Zone” episode called “The Fever.”

Even its thespic strengths and Aronofsky’s virtuoso technique, however, can’t overcome the structural weaknesses of “Requiem for a Dream.” It’s obviously an earnest attempt to portray the gruesome effects of addiction in a cinematically challenging fashion, but audiences would be best advised to reply to the invitation to watch this drug parable by heeding Nancy Reagan’s old mantra–Just Say No.