Depression can weaken bones, animal model shows

Last Updated: 2006-10-30 17:00:31 -0400 (Reuters Health)

JERUSALEM (Reuters) - Depression can lead to brittle bones, Israeli scientists report in a new study released on Monday that also suggests anti-depressant drugs may be useful in treating osteoporosis.

The scientists, at Jerusalem's Hebrew University, said mice that were given drugs to induce behavior similar to human depression suffered from a loss of bone mass, mainly in their hips and vertebrae.

After receiving anti-depressants, the bone density of the mice increased, along with their level of activity and social interaction, the scientists said.

"The new findings... point for the first time to depression as an important element in causing bone mass loss and osteoporosis," Hebrew University professor Raz Yirmiya, who took part in the study, said in a statement.

Depression activates the "sympathetic nervous system," which responds to impending danger or stress, causing the release of a chemical compound called noradrenaline that harms bone-building cells, the study showed.

Anti-depressant drugs block noradrenaline and reverse its negative effects, according to the findings, which will be published this week in the journal PNAS (Proceedings of the National Academy of Sciences).

A study published earlier this month by the Forsyth Institute in Boston found that fluoxetine, also known as Prozac, also increased bone mass in mice.

Osteoporosis weakens bones and makes them more likely to fracture. It is treatable, but affects millions and has the higher prevalence in postmenopausal women.