Traits likes sadness, pessimism and defeatism define depression, the world`s most frequently diagnosed mental disorder -- but it does have a positive side-effect.

A new study conducted by Bettina von Helversen, University of Basel, Switzerland and others, says such individuals perform better than their normal peers in sequential decision tasks.

Participants who were healthy, clinically depressed, or recovering from depression, played a computer game in which they could earn money by hiring an applicant in a simulated job search, the Journal of Abnormal Psychology reports.


The game assigned each applicant a monetary value and presented applicants one-at-a-time in random order. Experiment participants faced the challenge of determining when to halt search and select the current applicant, according to a Basel statement.

Besides resembling daily decision-making problems, such as shopping and dating, the task has a known optimal strategy. Depressed patients approximated this optimal strategy more closely than non-depressed participants did.

While healthy participants searched through relatively few candidates before selecting an applicant, depressed participants searched more thoroughly and made choices that resulted in higher payoffs.

This discovery provides the first evidence that clinical depression may carry some benefits. For decades, psychologists have debated whether depression has positive side-effects.

While researchers have recognised the flip side of depression, Paul Andrews and Andy Thomas, both from the University of Virginia, have proposed that depression may promote analytical reasoning and persistence -- that is, qualities useful in complex tasks.