What do you call a crossword puzzle without words? You call it Sudoku, the Japanese puzzle that’s engrossing Britons by the bushel.

Think I’m kidding? Check the effect:

Bernard Stay, 71, from St Albans in Hertfordshire, has had a more extreme reaction.

“I would really like my life before Su Doku [sic] back!” he pleaded recently on a website.

“I never thought I had an addictive personality, but Su Doku is definitely bad for me. If I don’t complete a puzzle before noon I get suicidally depressed for the rest of the day and even lose sleep fretting on what I’ve missed.”

Geez. Chill out and do a Jumble, dude.