Doubt fuels George Clooney's directorial debut. Can he cut it behind the camera? Is show business of any worth? Is TV innovator Chuck Barris (Sam Rockwell) really a CIA assassin on the side?

Barris is the real-life creator of US shows The Dating Game (Blind Date on the UK gogglebox) and The Gong Show (a precursor to Pop Idol, which saw talentless people gonged off stage when their performance became unbearable).

Dubbed the "Ayatollah of Trasherola" by critics, he copped to a more sinister side in his "unauthorised autobiography". He claimed that his overseas trips, chaperoning Dating Game winners, were a cover for his true calling: offing enemies of the United States.

Starting with a butt-naked, broken-down Barris standing in front of a blaring TV, "Confessions of a Dangerous Mind" travels back through its subject's "wasted life". Through his tail-chasing teens, TV genesis, and recruitment by government spook Jim Byrd (Clooney).

Layering on the stylistic tricks, Clooney zips through a very funny first act, before becoming a little bogged down as the action enters John le Carré territory.

It lacks a fear factor, as the espionage exploits are so clearly part of Barris' tortured psyche - a point underlined by the (mis)casting of Julia Roberts as a self-consciously glamorous spy contact.

But the script - by "Adaptation." scribe Charlie Kaufman - isn't really concerned with spy suspense. And as funny as it sometimes is, laughs are not a priority. Rather, as the dark and powerful conclusion demonstrates, it's about doubt and self-worth.

Barris needs to feel valued. The critics hate his shows, but not as much as he hates himself. He so despises his own lowbrow genius, he'd rather confess to killing than be remembered as a champion of trash TV.

This is a beautifully composed movie, shot through with sadness. A fair distance from flawless, but fascinating nonetheless.