The Diary of a Teenage Girl review: sex and the singular girl

Still supersaturated in the dysfunctional poison that turned Ireland and Britain into basket cases during the mid-1970s, we tend to underestimate the confusion that befuddled our American cousins at that time.

True, anybody old enough to remember the era will, while watching Marielle Heller's poignant debut feature, once again wonder at the stuff that even relatively poor US kids had. The adaptation of Phoebe Gloeckner's popular illustrated novel is suffused with various classes of unhappiness, but it can't help but romanticise its setting (San Francisco in 1976). Never mind the murders, the drugs and the political confusion. Breathe in the mists. Enjoy the jeans. Sob over Brandon Trost's sodden photography.

For all that, Heller’s film –a very Sundancey sort of hit at this year’s Sundance – wrestles with many still-uncomfortable truths about that period.

The excellent Bel Powley – gifted the face of an annoyed kitten that can’t decide whether it wants to be in or out – plays Minnie Goetze, an intelligent, sexually inexperienced 15-year-old living with her mom Charlotte (Kristen Wiig) in a typically hilly section of the City by the Bay. The film opens with Minnie confused at an apparent advance by Monroe (Alexander Skarsgard), mom’s half- bright boyfriend. Before too long, they are in bed together.

Author Gloeckner was, indeed, raised in San Francisco at that time. Still, it is hard to escape the notion that we’re looking at a retro-fitted version of the period. If kids in the 1970s really loved Iggy Pop as much as indie movies tell us, then the great man would have been bigger than David Cassidy. Minnie’s decision to record her diary on a cassette recorder (one entry taped, improbably, on a crowded bus) also looks a little like period fetishisation.

More interesting is the film’s engagement with the moral promiscuity bequeathed by the 1960s. The US right- wing has blamed the swinging decade for introducing hitherto puritanical Americans to a kaleidoscope of damaging temptations. More progressive thinkers have suffered confusions balancing the equation between liberation and personal indulgence.

Nobody could watch The Diary of a Teenage Girl, in which drugs befuddle family life and sexual license brings Minnie close to destruction, as any sort of advertisement for the post-1960s arrangement. At times, the film seems to be making the same unhappy noises about the sexual revolution that we read in Judith Rossner's troubled Looking for Mr Goodbar. Reaganism may not have been the right answer. But a question had definitely being asked.

The action is punctuated by key political events and cultural shifts. No clunking parallels are drawn between Patty Hearst's affection for her kidnappers and Minnie's mad passion for the hopeless Monroe, but the evidence is there for us to make the case on our own. A wild romp to Television's See No Evil (a little early, I fear) tells us that the punk experiment is about to leave its first impressions on the Petri dish.

Yet none of this would matter much if the story didn’t work on a human level. Powley’s casting is remarkable in a number of ways. Raised in Shepherds Bush, in her 20s when the movie was shot, she seems to perfectly understand the inner music of the American teen. The yearning for meaning comes through in her sublimated sexual fury and – expanded through animation of the freaked-out school – comic book art that genuflects to the character’s mentor, Aline Kominsky.

Almost everybody does bad things, but the script is generous enough to allow each character a moment of decency. Even Monroe appears to discover happy possibilities.

This is a gutsy, juiced-up film that manages to engage with a period and tell a few truths for the ages. All involved should be watched carefully.