Urine tests could detect Obsessive Compulsive Disorder

By Dr. Ananya Mandal, MDJan 6 2011

Australian researchers have found a novel and easy way to detect a common and debilitating anxiety disorder called the Obsessive Compulsive Disorder or OCD. Scientists at the Centenary Institute in Sydney discovered a gene responsible for a rare kidney disorder is also behind OCD. This may make detecting OCD easier through a simple urine test. This test could also identify babies with risk of early-onset OCD. OCD affects up to 3 per cent of all Australians and in its worst cases can be completely debilitating, causing people to have to stay at home. OCD sufferers feel intense anxiety and are compelled to practice rituals - such as hand washing or arranging objects.

According to Professor John Rasko current recommendations suggest screening babies for dicarboxylic aminoaciduria (DA), an inherited disorder of the kidneys. He explained, “This disorder affects the transport of two critical amino acids in nutrients - glutamate and aspartate… These two amino acids are crucial in many aspects of building the body's proteins, but also one of them, glutamate, acts as a transmitter in the brain… The transporter that pumps glutamate in the kidneys also transports glutamate in the brain and in the brain it functions as a signalling molecule.” The gene is the SLC1A1. “These findings prove for the first time that SLC1A1 is the affected gene in dicarboxylic aminoaciduria and demonstrate the crucial role that SLC1A1 plays in the kidney’s ability to process the essential amino acids glutamate and aspartate. Dicarboxylic aminoaciduria is a rare kidney disorder but this discovery may provide us with a clue to understanding OCD that affects approximately 3% of Australians. Due to the crucial role of SLC1A1 in normal brain function, the findings also have major implications for a likely genetic cause of some brain disorders like obsessive-compulsive disorder.”

He went on to say that people with OCD have too much glutamate because of a defect in the pump. This fact he said could help diagnose the condition. “This may provide us with a new opportunity to test people who have OCD with a relatively simple test of the urine…Although not everybody with OCD will have an abnormality in the urine test, what we'd like to be able to show in the future is that it will be able to provide insight into the mechanism by which this causes this otherwise debilitating disorder,” Professor Rasko said.

OCD expert Dr Mairwen Jones from the University of Sydney says early onset OCD affects about three per cent of Australians. She added, “It is the most intractable and disabling of the anxiety disorders… The earlier we can diagnose OCD the sooner we can start treatment to manage the obsessive and compulsive behaviours.”

The research was funded by the Australian National Health and Medical Research Council (NHMRC), the Australian Research Council (ARC), University of Sydney Bridging Support Grant, Rebecca L. Cooper Foundation and Cure the Future Foundation.