Something interesting happens to some comedians when they get successful. Sadly, it’s not the sort of interesting that makes them funnier.

John Cleese is one case in point, a wonderfully funny man once upon a long time ago, since known for corporate videos and tiresome books on therapy.

Mike Myers…well, I’d hesitate to call him a funny man at all, but it looks like he’s become the comedy equivalent of M. Night Shyamalan, each film worse than the preceding one until some kind of null point is reached at which even their creators must face up to the fact that they’ve been producing shit for some years.

Eddie Murphy, once a supremely funny man, now reduced to films in which he’s pretty much the only actor, cast against himself in a fat suit with alarming frequency.

It’s not pretty. And now it looks like Adam Sandler might be going the same way. Which is a shame. He showed real promise in his seemingly sincere chaotic instincts, which Paul Thomas Anderson harnessed to amazing effect in Punch-Drunk Love, a truly unsettling film about the mania that love can catch people up in.

Sandler’s new film is You Don’t Mess With The Zohan, and one worrying sign is that it’s got a serious undercurrent. In this instance, Sandler is attempting to mend the rift between Israelis and Palestinians through the healing power of humour. A noble intention, but comedy and nobility don’t really go together.

The plot works well enough, and I can imagine it being played straight as a touching piece of world cinema, as an Israeli soldier fakes his death to start a new life in New York as a hairdresser. Only, that arthouse version would have less emphasis on Sandler’s voluminous pubic hair, and the scenes with him fucking the matrons who come for his winning touch with a coiffure would probably be handled with more sensitivity.

It’s kind of entertaining, and there are a few genuine laughs to be had, but this is pretty thin stuff without the antic spirit of true comedy. It’s possible to deliver messages along with the laughs; that’s proven by Dodgeball, which really is as its strapline suggests a tale of underdogs triumphing over corporate jerks. But the laughs have to take priority over anything else for that approach to work. And unfortunately for Sandler, that isn’t the case with his new film. A shame – but maybe its failure will pre-empt a personal crisis for a canny filmmaker to capitalise on in years to come, and reignite the frantic energy that characterised Sandler’s earlier performances.