HANDSOME Devil kicked off the Glasgow Film Festival in enjoyably breezy fashion, so the choice to balance things out with something altogether darker was a wise one indeed as the event drew to a close last night.

Mad To Be Normal is an engrossingly off-kilter biopic from documentarian-turned-feature director Robert Mullan which explores the true story of RD Laing (David Tennant), the world-renowned Scottish psychiatrist.

In the 1960s Laing took his unconventional approach to Kingsley Hall in East London, a unique and controversial community for mentally ill patients where nature is left to take its course on psychosis and schizophrenia rather than just restraining and pumping them full of drugs. It’s a story that’s seen the light of day in many forms over the years, from plays and short films to documentaries and features.

And it’s not hard to see why it’s a subject of fascination. It’s an absolute gem of a real-life tale about a man hard to pin down in spite of his self-proclaimed clarity about what he was trying to do.

Tennant plays him with a captivating mixture of compassion, pomposity, sarcasm and an undeniable undercurrent of menace. You’re never truly comfortable in his company but nevertheless can’t resist spending time with him – a multi-faceted performance for a one of a kind real life personality.

Laing is a striking figure who wanders around his chosen institution telling any visitors who’ll listen about the ways in which his treatment differs to other doctors. He’s an imposing nurturer and a very specific kind of mad scientist whose questionable techniques fascinate, confound and enrage his peers in equal measure.

Is there a method in his madness or is he a danger to himself and his patients in spite of his indubitable empathy? We’re given plenty of breathing space to dig at the answer.

A wonderful cast around him put in the very definition of great supporting performances. Elisabeth Moss brings great life and energy to the film as Laing’s student admirer-turned-girlfriend Angie, who fully embraces him and his approach to psychiatry but soon comes to find she may have bitten off more than she can chew.

Michael Gambon has one of the film’s standout scenes as an elderly patient coerced by Laing to take LSD for the first time to try and unlock repressed memories. And Gabriel Byrne puts in a memorable turn as troubled patient Jim, who is as endearing as he is unpredictable.

This potent biopic is as unconventional as the approaches of its central figure, one dripping with woozy atmosphere, excellent period detail, unexpected emotional heft and an interesting sideways perspective on an uncomfortable topic. Above all else it’s an excellent showcase for Tennant’s inimitable, charismatic screen presence.