When it comes to wisdom and trying to make sense of life, one maxim towers above all others: there's always someone worse off. You'll find that gold glowing constantly in your mind during The Sessions, the true story of one man getting on with it (and, indeed, getting it on) and a movie with actors at the very top of their game. If you like a drama that does much for heart and head then don't miss it.

Mark O'Brien (Hawkes) is a poet and journalist who lives in Berkeley, California. Having contracted polio at the age of six, O'Brien has spent his life since horizontal, able only to move his head. With a team of carers and an iron lung for his bed, O'Brien lives at home but sees plenty of the outside world thanks to a portable respirator that keeps him alive for a few hours when he's away from the lung.

This life looks like torture, but here's the thing: O'Brien is one of the funniest and most optimistic people you're ever likely to meet, combining deadpan wit, sensitivity and the charm of a rogue. He's also a devout Catholic and that's put him in a right moral dilemma. While the majority of his muscles are wasted, a certain appendage isn't: O'Brien wants to have sex before marriage and, at 38-years-old, reckons he's close to his "use-by date".

O'Brien's quest for physical intimacy is accelerated when he is commissioned to write an article on sex and the disabled. He is given the contact details of Cheryl Cohen-Greene (Hunt), who works as a sex surrogate - a therapist helping the disabled overcome any awkwardness through, well, hands-on sessions. In order to make sure no-one gets too attached, these sessions are limited to six, and it is emphasised that they are a bridge to starting a relationship with someone else. And so O'Brien finds himself at a crossroads before the bridge: hide, or adopt the risk-taking attitude he inspires in others.

Every film fan has their Oscars grievances; there are three big ones for 2013: that Ben Affleck isn't nominated for Best Director for Argo; that Samuel L Jackson isn't among the Best Supporting Actor nominees for Django Unchained and that John Hawkes isn't on the Best Actor shortlist for The Sessions. Thankfully, Helen Hunt is nominated, but Hawkes should've been more than a spectator on the night. This is a very special performance, and, at the age of 53, says that Hawkes is only coming into his prime as an actor.

Hawkes' portrayal of O'Brien is as life-affirming as it is thought-provoking. Time and time again you're reminded how much we take for granted - and just how crippling the idea that we don't deserve happiness can be. Writer-director Lewin makes sure that O'Brien's story is neither too sad or sugar-coated and his collaboration here with Hawkes, Hunt and the ever-wonderful Macy as O'Brien's priest and pal celebrates the humour and tenderness that often end up as bit players in the movies that are our own lives. Here, you'll want nothing but the best for the people on screen, and hopefully leave the cinema thinking you don't deserve anything less, either.

Harry Guerin