TO READ: Depression's Devastating Self-Criticism Explained
When serious depression kicks in, one often-heard complaint is, "I do everything wrong." Now researchers have brain-wave evidence about where this perception may come from. Results from one study show that depressed people make no more mistakes than healthy controls -- but that they truly are better at detecting their errors.

Scientists measured two types of brain waves as subjects did a simple signal-detection task, and found that depressed people were just as quick and accurate as the non-depressed. No slowness or concentration problems were noticed. However, both types of brain waves -- one called error-related negativity, which measures brain resources used in early detection of errors, and the other called error positivity, which indicates error detection -- are exaggerated in depressed people.

Those responses indicate that the depressed group used more of their brain resources to detect errors. Researchers suggest that when they make a mistake, depressed people are more likely to notice it than a healthy person would be. While this extra acuity might be a good thing in certain situations, it also may be responsible for the hyper-criticism often felt during the illness. Something to bear in mind when that I-can't-do-anything-right feeling kicks in!

For more info: American Journal of Psychiatry 2007 164:58.