Recent News and Articles on the Keywords: depression + genetic + 0.21  Related to the article below (Last Update: 8/5/2008)

Depression could be genetic

Life can throw up some tough situations, with divorce, bereavement or losing a job being among the most difficult to cope with.

And whether our reaction is to sink into depression or bounce back from adversity could be down to a single gene.

Scientists have found that our DNA make-up affects how well we deal with such major personal events.

The gene - called 5-HTT - has two versions, 'sensitive' and 'coping'.

Those with the first are two-and-a-half times more likely to succumb to black moods, sadness and insomnia.

However, those born with the coping version tend to stay on an even keel after stressful events.

Experts said the study proves for the first time a direct genetic link between distressing events and emotional well-being.

Researcher Dr Terrie Moffitt, of King's College London, said: "We believe the gene helps influence whether people are resistant to the negative psychological effects of the unavoidable stresses of life."

Katrina Kelner, deputy editor of the journal Science, which publishes the study's results today, said: "This is tremendously exciting.

"We now understand the biological basis of some people's ability to bounce back successfully from adverse life events."

Researchers looked at the lives of 847 people over five years and studied how well they coped with prolonged illness, bereavement, redundancy and relationship breakdowns.

Along with colleagues in the U.S. and New Zealand, they focused on those who had suffered more than one such stressful event. Among people with the 'sensitive' version of 5-HTT, 43 per cent developed depression - feeling permanently sad for at least two weeks.

But only 17 per cent of those who had the 'coping' version fell into melancholy, the same level as people who have not suffered any stressful events.

The 5-HTT gene regulates the flow of serotonin, a chemical messenger in the brain that carries signals between nerve cells.

The 'sensitive' version is not as effective at controlling the compound, affecting a person's emotional state.

Each person carries two versions of the gene, one inherited from each parent, which can be told apart by their length. The 'coping' version is 'long' and the 'sensitive' is 'short'.

Those most at risk from stress were those who had two 'short' versions. Tests showed they were almost three times more likely to think of or attempt suicide than those with the two 'long' 5-HTT genes.

In the King's study, 17 per cent of individuals carried two 'short' copies while 32 per cent carried two 'long' copies.

The others ranged between the extremes, carrying one of each.