YOU KNOW THAT a middle-aged novelist is running out of ideas – yes, I’m looking at you, Martin Amis – when his or her novels start to be about middle-aged novelists.

This is only Judd Apatow's third film as director, but already the one-man comedy machine, creator of The 40-Year-Old Virginand Knocked Up, has got round to making a picture about the trauma of being a successful funny guy.

As if that didn't sound indulgent enough, Funny People(a disastrously hubristic title, by the way) also offers roles to the director's wife, both his children and a legion of his celebrity buddies. Look at me! Look at me!

Well, you might reasonably point out that Pedro Almodóvar's Broken Embracesdeals, in part, with the discontents of being a Spanish film director. Unfortunately, Funny Peoplehas not a modicum of that film's discipline. Starring Adam Sandler as a superstar comedian facing up to a potentially terminal illness and Seth Rogen as an up-and-coming acolyte who becomes the older man's assistant, the film meanders around aimlessly for two and a half hours without ever finding a worthwhile identity.

Much of the early, moderately successful opening act focuses on the amusing bickering between Rogen and two equally insecure contemporaries: Jason Schwartzman is sleek and clenched; Jonah Hill is large and dissolute. When Sandler’s characteristically creepy, deeply compromised icon turns up unexpectedly at a small comedy club, he catches Rogen’s act and, eager to change his life following unhappy medical news, asks the man to come round and help with paperwork and punchlines.

Then, just like that, Sandler gets better and, failing to generate this year's Sideways, they embark on a road trip to San Francisco. There, they encounter Sandler's ex-wife (Leslie Mann, still Apatow's squeeze) and her aggressive Australian husband (Eric Bana, not as funny as he should be).

What on earth does Funny Peoplebelieve itself to be? Plots, themes and characters are summoned up, only to be dropped moments later as a child might drop an unwanted toy. It's unclear how unlikable or how unfunny Sandler is supposed to be. Is Rogen supposed to be the film's conscience? Who knows?

At one stage, the characters whinge about having to watch a film starring Sandler as a baby with a grown man’s head. Lucky old them. I had to watch Judd Apatow’s midlife crisis.

Also opening Opening today but not previewed for Irish critics is The Final Destination(15A cert, gen release, 81 min), presumably the final instalment in the gory horror franchise.