A suspect gene linked to major depression has been uncovered, potentially paving the way to new treatments.

German scientists made the discovery after comparing DNA from more than 15,000 depressed and healthy patients.

Altered letters in the genetic code were identified that were clearly associated with serious depression.

They appeared to influence a gene called SLC6A15 believed to regulate an important brain signalling chemical, glutamate.

“Because it is assumed that the communication between the neuron clusters is disturbed in depression, we considered whether the gene we had identified could possibly influence this process through glutamate,” said lead researcher Elisabeth Binder, from the Max Planck Institute for Psychiatry in Munich.

Tests showed that the DNA changes affected the gene’s activity, especially in the hippocampus brain region which plays a vital role in memory. In depressed patients, the SLC6A15 gene was less active and certain regions of the hippocampus were reduced in volume. The research is reported in the journal Neuron.

Co-author Dr Martin Kohli, also from the Max Planck Institute, said: “Current treatments for major depression are indispensable but their clinical efficacy is still unsatisfactory, as reflected by high rates of treatment resistance and side effects.

“Identification of mechanisms causing depression is pertinent for discovery of better treatments.”