SYDNEY, 12 July 2006 - A gene has been discovered by Canadian researchers that makes people more susceptible to major depressive disorders, throwing into question the way depression is currently being treated.
Nicholas Barden, who leads a team of researchers from the department of Neuroscience at the Centre hospitalier de l'Université Laval (CHUL) Medical Research Centre in Quebec, said, "This is a major breakthrough in the realm of psychiatry and will have groundbreaking implications for diagnosis and the development of new anti-depressant treatment."
According to Beyond Blue, an Australian society for depression, around one million Australian adults and 100,000 young people live with depression each year.
"The actual gene, known as P2RX7, is found in humans and animals and is responsible for depression. It has taken many years to find," said Barden.
The mood disorder has often been associated with the serotonin system in the brain, because serotonin-boosting drugs are effective anti-depressants. "What is particularly exciting is that P2RX7 has nothing to do with serotonin," said Barden.
P2RX7 plays an important role in the brain's response to inflammation, which is known to be part of many neuropsychiatric disorders. The activity of the gene is also affected by stress hormones, suggesting a relationship between depression and severe stress.
"A person may have the mutated gene, but its 'default setting' means that they may not develop depression. We don't yet know how P2RX7 works and we still believe that a multitude of genes feed into the same pathway that may induce depression," said Barden.
Identifying this gene opens the door for anti-depressants in the future that could target the gene directly. Because anti-depressants currently target the serotonin system, P2RX7 is largely unaffected.
But so far in animal studies, chemicals that trigger P2RX7 have an immediate anti-depressant action. This brings hope to patients and their doctors of a new generation of anti-depressant medication, with a new mechanism of action, and a whole new level of results.
