Depression And Osteoporosis Connection Shown By Hebrew University
Researchers
Depression can cause a loss of bone mass, leading to
osteoporosis and fractures, say researchers at the Hebrew University of
Jerusalem.
Their findings constitute a significant step in understanding the interaction between the mind and the skeletal system. The researchers demonstrated the efficacy of anti-depressant drugs in preventing bone mass loss.
Loss of bone mass is the leading cause of osteoporosis and bone fractures among the aged in general and among post-menopausal women in particular. Several studies
indicate that people with major depression generally have lower bone mass density compared to control samples. No direct link between these two conditions has been established.
To examine the connection between depression and bone mass loss, the researchers used a model involving laboratory mice. Following the induction of a depression-like condition, the mice developed behavioral symptoms mirroring those seen in depressed humans, including a reduction in pleasurable activity and in social interaction.
After four weeks in a depressed state, the mice showed dramatic bone mass loss, including in the hip bone and vertebrae. This loss was caused by impairment in the bone renewal process, essential to maintaining normal bone density. This impairment was caused by a reduction in the number of bone-building cells, called osteoblasts.
The laboratory tests showed that chronic use of an anti-depressant drug halted the depression and the loss of bone density.
The researchers described the process connecting depression to the
skeletal structure and found depression sets off a neural system connecting the brain to the internal organs, including the skeleton. This system is called the "sympathetic nervous system." Its activation causes the secretion within the bone of a chemical compound called noradrenaline, which has a detrimental effect on the bone-building cells. Chronic treatment with a drug that blocks noradrenaline in the bone also blocks the detrimental influence of depression on the bone.
This research serves as the basis for new, efficient drugs to treat
osteoporosis, which is the most prevalent degenerative disease in western
society.
"The connection between the brain and the skeleton in general, and the
influence of depression on bone mass in particular is a new area of research
about which we still know very little," said Prof. Raz Yirmiya, head of the Brain and Behavior Laboratory. "The new findings, which we have discovered in the Hebrew University laboratories, point for the first time to depression as an important element in causing bone mass loss and osteoporosis." This research developed a new area of research called 'neuro-psycho-osteology,' which deals with the connection between
the brain, mental states and the skeleton.