Alice Jones: The messy climax of confessional art

No feeling or whim is now too trivial to be immortalised in oil or pencil

As anyone with siblings knows, you should never let your younger brother near the paintbox. This week the artist Paul Karslake, better known as the brother of Jo Wood, who is, in turn, better known as the estranged wife of Rolling Stones' guitarist Ronnie Wood revealed his latest painting. In it, a vampiric (yet, strangely, mahogany tanned) Ronnie is portrayed with narrowed, bloodshot eyes, sinking his bloodied fangs into the snow-white neck of a young, beautiful blonde.

Gossip hounds pricked up their ears. For here, painted large, was the brother-in-law's none-too-subtle take on the break-up of the Woods' 23-year marriage, following the sexagenarian rocker's affair with a Russian cocktail waitress 42 years his junior. According to the press release (all good art comes with a press release), Karslake painted the piece, "to portray his disgust at the treatment of his sister, Jo Wood".

"I've been really upset over the events and my brush just did the talking," explained the artist. A mortified Jo Wood can't be the only one wishing her brother's brush had kept its mouth shut. Karslake might be upset, but does anyone need to see the lurid results splashed across a canvas, still less explained on an accompanying piece of paper? He could have just crossed Ronnie off his Christmas card list.

Karslake, though, is not alone. Earlier this month, Jasper Joffe set about healing his broken heart when his five-year relationship broke down by selling every last one of his possessions – from trinkets to teddy bears – in an East London gallery. "Maybe if the show goes well, I hope we can get back together," mused the artist, pathetically. "My mother and father are worried," he added.

"Worried"; "upset": on such feeble emotional foundations great art is not made. Van Gogh did not slice off his own ear because he was feeling mildly put out. But this is the golden age of I-painting, the messy climax of confessional art where no feeling or whim is too trivial to be immortalised in oil or pencil. It's easy to attribute the cultural trend to today's reality television-obsessed, Jade Goody death-watching, mis lit-reading, endlessly Twittering society.

In fact, artists have always revealed themselves and their fragile state, from Van Gogh's mutely miserable bandaged self portraits up to Tracey Emin's visceral scrawls. It's the lack of gravity or even real conviction behind this new soul-bearing which makes it so excruciating.

On London's South Bank, the Walking in my Mind exhibition promises visitors an insight into the artist's brain – which in the case of the late Jason Rhoades turns out to be cluttered with hardcore porn and engorged genitalia. Too much information, Jason! Meanwhile in Trafalgar Square, Antony Gormley offers an endless stream of people on the fourth plinth filling in their expenses , asking passers-by "am I hot?" and cutting their hair. Sometimes, some things are better left unsaid.

If, though, artists really must vent their spleen, they should look to Salvador Dali for lessons in painterly bile. When, in 1949, his sister published a biography which contradicted the artist's own carefully wrought mythology, he responded only five years later, with the rear-end portrait of a woman, "Young Virgin Auto-Sodomised by her own Chastity", and let the world draw its own conclusions. The fine art of revenge, indeed.