NIMH, America's National Institute of Mental Health, has published findings relating spatial memory - essentially remembering where objects are relative to one another - to a variety of mood disorders. Previously, researchers had used two-dimensional memory tests to predict damage to the hippocampus, which might also manifest itself as depression, but specially designed videogames produce a far more refined calibration and can measure dysfunction that, otherwise, would have gone undetected. Gamers wondering whether their inability to score more in Brain Age or complete the last world in Mario vs Donkey Kong 2 may be a sign of hippocampal malformation should probably think about something else, and give NIMH a wide berth. Look what almost happened to Mrs Frisby.