Patients with severe mental disorders are going to decide this year's Turner Prize: the annual award presented to a British visual artist who is unskilled at drawing or painting. According to organisers at the Tate Gallery, a panel of judges will be announced shortly, and those selected must demonstrate 'serious cognitive dysfunction when evaluating aesthetic value'. In prior years, the award has been determined by a 'coked-up' troop of chimpanzees and a marine-based panel of sea cucumbers: a species of animal that might lack a brain, but can at least opt to eject long sticky tubes from its anus to ensnare unwitting predators.

"Don't misinterpret the clinical term 'outpatients'," said psychiatric nurse Sarah Treswell. "This motley crew have all been hospitalised for years. We're just giving them a day out at Tate Britain. They've been discussing the question 'what is art?' during therapy, and they tend to exhibit more destructive and suicidal behaviours than usual. Let's hope they achieve consensus on the day. We're slightly concerned about schizophrenic Nigel's potential reaction to that enormous pair of golden buttocks."

In addition to a giant sculptured backside, the shortlist also includes a 'mesmerising' pile of copper coins, an 'impenetrable' brick suit and a 'beguiling but maddening' toy train. According to critics, however, nothing comes close to last year's winner: a regeneration scheme for derelict houses in Toxteth, whose majesty has been equated with the ceiling of the Sistine Chapel.

"This year's entries are very cryptic," said BBC arts editor Will Gompertz, after spending 3 hours staring at a 'bewitching' collection of dangling chastity belts. "I haven't enjoyed being so confounded and perplexed in a long time. The shortlist is full of speculation, curiosity and whimsy, unfixed by medium or method...oh shit, I just can't do this any more. I want to kill myself. Nigel! Can I come back to the hospital with you?"