Dir: Betty Thomas. US. 2000. 103 mins.

Prod cos: Tall Trees, Columbia Pictures. US dist: Sony Pictures. Int'l dist: Col TriStar. Prods: Celia D. Costas, Jenno Topping. Scr: Susannah Grant. DoP: Declan Quinn. Prod des: Marcia Hinds. Ed: Peter Teschner. Music: Richard Gibbs. Main cast: Sandra Bullock, Dominic West, Steve Buscemi, Viggo Mortensen, Dianne Ladd.

The threadbare premise of a woman struggling to overcome her alcoholism is spiked with new life thanks to a smartly comic screenplay from Grant, currently one of Hollywood's most productive writers of female-slanted stories: her credits include the current box-office smash Erin Brockovich, Pocahontas and Ever After.

Similar to Julia Roberts in Erin Brockovich, 28 Days requires its star, Bullock, to display an edgier-than-usual side to her screen persona, and while the actress seizes the opportunity with both hands, the movie's success will largely depend on whether her box-office pull can overcome audience resistance to an often prickly character and unpromising subject matter.

After creating a drunken scandal at her sister's marriage and crashing the wedding limo while deep under the influence, Gwen (Bullock) is ordered by the court to spend 28 days at a rehab clinic where she meets a motley assortment of individuals. Initially she is dismayed by the blanket ban on mind-enhancing substances (not to mention mobile phones) and the sloganising, chanting and touchy-feely displays of group solidarity. But, helped by the clinic's battered councillor who has also been through the mill (Buscemi), she develops an affection for her fellow inmates and confronts her own past.

The early scenes feel rushed and under-developed, with detail of plot sacrificed by Thomas to broad, slapstick comedy. Gwen is supposedly a "successful New York writer", but there's no sense of what she writes (or when) or of the fast-lane lifestyle being fuelled by the booze, while her hedonistic boyfriend (West) is barely established as a character.

But the film gathers momentum as it develops its ideas (a neat running gag follows the inmates' socially acceptable addiction - to a terrible daytime television soap opera) and introduces the droll supporting characters, finally contriving to combine an upbeat note with a bittersweet, slightly open conclusion.