Depression, typically diagnosed in an interview with a therapist, can be diagnosed through blood test, according to a new study recently released by journal Translational Psychiatry.

Researchers not only developed a blood test which can find molecules in the blood associated with depression, but also figure out which patients will benefit most from behavior-based therapy as a treatment.

The new study, led by Northwestern University psychiatry professor Eva Redei, focused on nine markers whose levels in the blood differed between people with and without depression.

Depressed people went on to receive cognitive behavioral therapy.Redei and her colleagues followed them to see if they could find any additional markers for whether these patients responded well to the therapy or not.

Redei said she looked for a biological test because it is the reference how she views depression, one of the most common of all mental disorders.

"I think it came from my firm belief that depression is an illness, just like any other illness is. And if it is an illness, that means you can also diagnose it in an objective manner."she said.