Depression is the most common psychiatric disorder

An article titled, "Can 'blue' genes affect mood and movement?" published in the journal Neurology has revealed that while Parkinson's disease typically brings to mind symptoms such as tremors and slow movement, nearly half of all Parkinson's patients also suffer from depression.

"Many &to=http:// english.pravda.ru/printed.html?news_id=13726 ' target=_blank>patients assume that's it's normal to feel this way.

They might say, 'If you had Parkinson's disease, you'd feel this way too.' That's not true.

If you treat the depression, they'll still have the other &to=http:// english.pravda.ru/society/2003/03/18/44589.html ' target=_blank>symptoms of the disease, but they feel better. It's one aspect of the disease that may be very treatable," said Irene Richard, neurologist at the University of Rochester Medical Center.

"People diagnosed with other serious diseases that may also be disabling, such as rheumatoid arthritis, aren't nearly as likely to become depressed," he added, reports Hindustan Times.

Researchers at Columbia University in New York, for instance, have found a gene known to cause a movement disorder known as dystonia causes a type of early-onset depression.

Parkinson's is also a movement disorder, caused by the destruction of brain cells that produce an important message-carrying chemical called dopamine.

An estimated 1 million people in North America have Parkinson's disease.