Jane Magnusson’s documentary Bergman: A Year in a Life begins in the pit of Ingmar Bergman’s dyspeptic tummy. A fuzzy black-and-white image shows him waking up around 4am, ‘the hour of the wolf’ as it is called in one of his most haunted films. Then, as he says, he waits for his ulcerated stomach to fire up its blowtorch.

After that grumbling overture, Bergman has trouble tunnelling out of his dank internal prison. There are two ways to expunge his sickness, and he tries them both. One leads down and out, in a spluttering expulsion: Bergman describes his life as ‘shitty’ and ‘piss-awful’. The other, more emetic, sends the stomach’s contents violently upwards. Scourging some actors who, in his view, had sabotaged his production of Molière’s The Misanthrope, Bergman called for a bucket, afraid that disgust would trigger his ‘vomiting reflex’.

Seen like this, Bergman resembles the noxious narrator of Dostoevsky’s Notes from Underground, who at the outset calls himself a sick, spiteful, unattractive man and blames his temperament on a diseased liver. Former collaborators describe a reign of terror during Bergman’s rehearsals, made possible by ‘arse-lickers’ with ‘a blatant lack of moral courage’. Others remember furtive plans to steal one of the digestive biscuits he unceasingly munched to quieten his stomach. Despite the biscuits, an actor whose prized monologue Bergman capriciously cuts from a play calls him ‘a carnivore’ and says he gobbled up weaklings.

Magnusson concentrates, as a somewhat flimsy pretext, on Bergman’s ‘mad year’ of 1957, when he made The Seventh Seal and Wild Strawberries as well as directing a stage performance of Ibsen’s Peer Gynt. Her interviewees assume that such productivity was fuelled by mania: one actress points out that Rainer Werner Fassbinder kept up a similar pace by using amphetamines and suggests that Bergman energised himself by exploiting a concurrent set of wives, mistresses and muses. Nowhere is there a glimpse of the more hedonistic Bergman who made Summer with Monika and Smiles of a Summer Night, or of the innocent, infantile vision he brought to his film of Mozart’s The Magic Flute.

Genius is expected to be an agonising state, a torment like that suffered by Prometheus, who, punished by Zeus for his creativity, writhed on a mountain peak while an eagle gnawed on his innards. Combining self-disgust and self-admiration, Bergman often adopted such a Byronic posture. He admitted that he was a rat, a cheat, a liar, ‘an absolute failure as a human being’; by way of compensation he determined, he said, to be the best director in the world. In both respects, he exaggerated.

Magnusson has called Bergman ‘the most interesting Swede ever’. It’s a revealing choice of adjective, which queries his status as a national hero and presents him instead as a psychiatric conundrum. He made Sweden globally famous, someone says in the film; Sweden, however, may have preferred to be modest, marginal, unnoticed. Certainly the foreign adulation Magnusson presents shows up the fatuity of Bergman’s admirers. Barbra Streisand babbles semi-coherently, while the talk-show host Dick Cavett is so overcome by being granted an interview that he addresses him as Ingrid Bergman. Such fawning made Bergman think himself sacrosanct: when he was investigated for tax fraud in 1976, he first retreated to hospital with a nervous breakdown and then – in another gesture worthy of Byron – stormed off into exile in Munich. Somewhat cravenly, the Swedish government begged him to return. ‘We miss you,’ says the abject education minister in a public speech excerpted here.

In Magnusson’s view, all Bergman’s characters were projections of himself. She misunderstands the way dramatists invent other people, sometimes as surrogates or scapegoats, but also to examine their own failings. Bergman always claimed to have been the victim of beatings by his father, a sadistically strict Lutheran minister; Bergman’s brother, Dag, insists that it was he who received the floggings, which Ingmar escaped. Magnusson takes that appropriation as evidence of Bergman’s untrustworthiness and his predatory ego. Couldn’t it also be penance or empathy – a desire, which underlies much drama (including that of Shakespeare), to feel the pain of others? Bergman’s most complete self-reckoning can be found in the figure of the professionally driven, emotionally withdrawn pianist in Autumn Sonata. The role is played with lacerating honesty by Ingrid Bergman: perhaps Cavett’s flustered slip of the tongue was prescient.

The documentary’s climax comes when Thorsten Flinck, the young actor and director who took the blame for the truancy of his colleagues in that production of The Misanthrope, recalls Bergman upbraiding him as a ‘repulsive bastard’ in an episode of savage ‘psychological torture’. Twenty years after the event, Flinck acts out Bergman’s rant, with all the man’s doddery tics and spitting slang intact: it is a killing impersonation. But Liv Ullmann, the only one of Bergman’s lovers to testify before Magnusson, insists that he enriched her life and never did her any harm, and wipes away a tear. We are left to consider our verdict.

In search of extra evidence, I watched a television interview given by the octogenarian Bergman in 2000. Here, with #MeToo far in the future, he and the actor Erland Josephson wonder if they might be ‘the last generation to enjoy these generous and indulgent women’ who forgave them for being unfaithful husbands and absent fathers because they were artists. Chuckling, Bergman shifts in his chair and apologises to the cameraman for upsetting the focus; he explains the move by saying that he had a twinge down below. I doubt that Magnusson would be appeased, but it’s good to know that Bergman was sometimes a pain in his own arse.