Let’s get one thing straight. The Wackness is not a stoner comedy, it is a comedy drama featuring stoners. It’s a subtle but important distinction that will make all the difference to your enjoyment of the film. A stoner comedy, not that I am a connoisseur of the subgenre, will feature Rizla-thin characterisation and unlikely situations played for laughs. The Wackness, conversely, is a fundamentally serious rites of passage tale where the humour emerges naturally from the fabric of the story.

Written and directed by Jonathan Levine, the film is set in 1994 though you’d be forgiven from its very brown look for thinking that we’d gone further back into the 70s. The soundtrack will soon dispel you of that idea: high school student Luke Shapiro is a white hiphop fan who says he’s not a virgin but hasn’t actually had sex. That’s just one of the reasons he’s having appointments with psychiatrist Jeffrey Squires (Ben Kingsley: another indication that this isn’t a mere stoner comedy, not known for heavyweight acting talent). And it’s their relationship where the stoner confusion comes in, since Luke pays for his counselling sessions with weed, and bong-tootin’ Jeffrey is looking for a better future just as much as his teenage client is.

Luke is inhabiting a no man’s land between high school and college, not helped by his empty relationship with his parents. Looking for something to occupy himself in the summer, he sells weed from an ice cream trolley in Central Park, and befriends his shrink’s stepdaughter Stephanie. They become close, despite the psychiatrist steering Luke away from his charge, and she relieves Luke of his virginity in a scene that’s funny and tender and plausible; exactly the sort of sex scene you wouldn’t see in most teen comedies.

Yes, it’s the sort of story where everyone ends up where you expect, but that’s true of so many films. What matters is the journey, and the performances. And it’s in this respect that The Wackness becomes so much more than its constituent parts. There’s clumsiness here, and warmth, and confusion, and anguish, and all these emotions are brought to life with relish by the cast. Ben Kingsley is on fine form, a middle aged hypocrite with pompous leonine hair and a line in bogus wisdom that even he finds suspect when it’s repeated to him.

I found it all refreshing and enjoyable, though my friend M thought it obvious and poorly written. It may come down to how you feel about spending close to a couple of hours in the company of characters who haven’t got their acts together. Hey, I do it often enough in real life so can easily excuse it on screen, and personally I found it almost as entertaining in its effortless way as Little Miss Sunshine. Put it this way, if you thought the latter was a formulaic road movie, you’ll find this a formulaic stoner comedy. Make your decision on that basis…