Even as contemporary society prizes personal happiness above all else, a fascinating study suggests that sadness is good for the health.

We all go through rough patches sometimes, whether it's after the break-up of a relationship, the death of a loved one, and of course in the current phase of the global financial crisis, losing a job.  Perhaps, then, it is time to embrace our miserable side.

Mental health experts caution that the increasing tendency to take a pill to beat the blues could actually affect human evolution. Sadness, they argue, serves an evolutionary purpose - and if we lose it, we lose out.

Scientists believe that in humans sadness has a further function: it helps us learn from our mistakes.

"When you find something this deeply in us biologically you presume it was selected because it had some advantage - otherwise we wouldn't have been burdened with it. We're fooling around with part of our biological make-up," said psychiatrist Professor Jerome Wakefield, of New York University.

"I think one of the functions of intense negative emotions is to stop our normal functioning - to make us focus on something else for a while," stressed Wakefield, the co-author of 'The Loss of Sadness: How psychiatry transformed normal sorrow into depressive disorder.

It also might act as a psychological deterrent to prevent us from making those mistakes in the first place, reports New Scientist.

Wakefield said the risk of sadness may deter us from being too cavalier in relationships or with other things we value.

In effect, medicating sadness, it has been suggested, could blunt the consequences of unfortunate situations and removing people's motivation to improve their lives.

Then there is the notion that creativity is connected to dark moods. There is no shortage of great artists, writers and musicians who have suffered from depression or bipolar disorder.

Modupe Akinola and Wendy Berry Mendes of Harvard University found that people with signs of depression performed better at a creative task, especially after receiving feedback that was designed to reinforce their low mood.