Depression genes show when the drugs won't work

[The Straight Story]

Depression genes show when the drugs won't work

When depressed or chronically anxious people are prescribed drugs to treat their condition, it can take weeks before they know whether the pills have worked or not. Now psychiatrists have laid the foundations for a genetic test that could bypass that trial-and-error process by identifying patients who will not respond to particular drugs.

The researchers focused on a brain mutation that predisposes humans to depression and related disorders. They engineered mice to express the same mutation and found that the mice displayed classic signs of rodent anxiety. What's more, when given the widely prescribed drug fluoxetine, also called Prozac, the mice showed little improvement.

If the same happens in humans, it might help to explain why around 60% of patients given drugs for depression do not respond to the first medication that they are prescribed, say the researchers, led by Francis Lee, of Weill Medical College of Cornell University in New York.

Beating the blues

A range of drugs called selective serotonin-reuptake inhibitors (SSRIs) are widely used to treat depression. They all work by increasing the amount of serotonin, a chemical linked to emotional state, available to neurons in the brain.

But evidence is emerging that serotonin may not be the whole story. In 2003, for example, it was reported that fluoxetine may also work by bolstering neuron growth in the hippocampus, a region associated with learning and memory (see 'New nerves may fight depression').

http://www.nature.com/news/2006/061002/full/061002-10.html