Researchers have come up with a new hormone study that can better distinguish between the symptoms of depression and schizophrenia – two mental disorders that start off with non-specific and relatively mild symptoms.

According to latest statistics by the Centers for Disease Control and Prevention (CDC), United States, as many as 300 million people are affected by depression worldwide, while schizophrenia affects as many as 51 million people. Medical practitioners have a hard time distinguishing between the two disorders in the initial phases because they do not have specific symptoms that could hint at either one of the two.

Researchers at Yale University in Connecticut, US infused patients with a high concentration salt solution to induce the release of the hormone arginine-vasopressin (AVP), and then measured the level of the hormone in their blood. Researchers found that AVP release can distinguish schizophrenia from depression. Depressed patients showed an increased release of the hormone, while patients with schizophrenia showed a decreased response.

The study and its results published in Experimental Physiology reveal that the novel method will help identify people whose depression or schizophrenia involves signalling via a receptor called NMDAR, and differentiate between the two diseases. In patients with schizophrenia the NMDA receptor signalling may be decreased, while it might be high in those with depression.

This hormone test may be a simple way to distinguish and identify patients with NMDA receptor malfunction in each disorder, the researchers said. Distinguishing this specific form of these diseases could allow for earlier and more accurate diagnoses as well as more targeted treatment, Gunduz-Bruce added.