A blood test for depression has been developed by scientists.
They hope it will drastically speed up the diagnosis time for the condition and lead to quicker treatment.
At present, clinical depression can take several months to diagnose as doctors try to decide whether the patient has the condition or whether they are simply experiencing natural feelings of sadness caused by an event or tragedy.
But scientists from Northwestern University in Chicago say they have identified nine chemicals in the blood which are raised during depression.
They have devised a blood test which measures three of these chemicals to diagnose depression.
The researchers measured chemical levels in the blood of 32 patients with severe depression and compared them to 32 non-depressed individuals.
In a study published in the journal Translational Psychiatry, lead researcher Eva Redei wrote: ‘Abundance of nine transcripts (chemicals) differed significantly between subjects with major depressive disorders and non-depressed controls, suggesting this could be diagnostic in the clinical population.’
Many of us suffer from mild depression from time to time, which can be a spell of being down for a few days.
At its most severe, however, it can last for years with sufferers feeling that life is not worth living but with no obvious cause.
Research has also found that it may be genetic with people more likely to get depression if there is a family history.
Last year, researchers from the World Health Organisation said depression is the biggest cause of disability worldwide after back pain, but was often overlooked by doctors, with only a fraction of patients being offered treatment.