Poet Sylvia Plath once described her despair, wrought by a lifelong battle with depression and mental illness, as “owl’s talons clinching my heart.” Anyone who has ever suffered from depression can certainly appreciate the aptness of this description.

And, apparently there are many people all across the globe who have suffered similarly, according to the 2010 Global Burden of Disease study; researchers indicate that depressive disorders are the second leading cause of disability in adults.

Depression Defined

Major depressive disorder (clinical depression) affects 6.7% of adults in the US every year – those diagnosed have experienced at least one episode that has lasted for at least two weeks.  A depressive episode is defined as a depressed mood that lasts all day every day for a significant period of time. MDD prevents a person from functioning normally and interferes with work, sleep, appetite and quality of life.

Dysthymia is a milder, chronic form of depression that lasts at least two years; although those suffering from dysthymia may be able to function, their quality of life is significantly impaired.

Through the advent of magnetic resonance imaging (MRIs) researchers and physicians have determined that the brains of those suffering from a depressive disorder actually look different than others. The areas of the brain that regulate mood, thinking, sleep, appetite and behavior appear different than what is considered “normal.”

The authors of the study, which is published in the journal PLOS Medicine, contend that having this awareness – that depression is as wide spread as it appears to be — can be factored in when addressing public policy in the future.

Despite the fact that advances in the treatment of depression with antidepressants and cognitive therapy have done much to mitigate the suffering of many since Plath’s suicide in 1963 at the age of 30, depressive disorders are still a bit of a mystery. Even though depression can be detected in an MRI, what exactly caused it in each individual case can’t be determined.

However, the National Institute of Mental Health asserts that in general, depression can be caused by the following:

• Genetics (Sylvia Plath’s son Nicholas suffered from depression as well; he committed suicide in 2009)
• Biology or brain chemistry
• Environment
• Psychological issues