Most of us have seen it happen: a friend or colleague with enviable energy and dedication to a stressful job suddenly burns out. In place of tireless toil comes un­relenting exhaustion, difficulty falling asleep, low mood and a sense of inefficacy. These symptoms may look a lot like depression, but new research suggests that burnout is subtly different in the body and brain.

Although burnout is not recognized as a distinct psy­chiatric disorder, it seems to cause a unique profile of changes to neurological functioning, ac­cording to work by psychologist Agneta Sandström of Umeå University in Sweden. Sandström compared women with burnout, known formally as exhaustion syndrome, to women with major depression, and she found subtle but significant differences between the two groups. For instance, both groups of women had sleep difficulties, but women with depression reported waking too early, whereas women with chronic burnout had difficulties falling asleep.

Sandström also asked healthy women and those with ex­haustion syndrome and major depression to complete a work­ing-memory test. Both depressed and burned-out women found it hard to focus and remember simple details, compared with control women. But women with exhaustion syndrome had even lower brain activity, measured by functional MRI, during these memory tests than depressed women did.

Over time, Sandström says, small daily stressors can accumulate to create chronic burnout. By coping better with these seemingly insignificant pressures, people may be able to reduce their risk of developing exhaustion syndrome. “It’s okay to get stressed, but you also have to find time during the day to rest,” Sandström says. Just as your muscles can get tired, so can your brain. “We need to think about how much the brain can cope with during a normal workday,” she says.