The researchers say their findings constitute a significant step forward in understanding the interaction between the mind and the skeletal system. Based on their findings, the researchers have already been able to demonstrate the efficacy of anti-depressant drugs in preventing bone mass loss.
In order 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 behavioural 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 laboratory animals showed a dramatic bone mass loss, including in the hip bone and vertebrae. This loss was caused by impairment in the bone renewal process, which is essential to maintaining normal bone density. This impairment was caused by a reduction in the number of bone-building cells, which are called osteoblasts.
The laboratory tests showed that chronic use of an anti-depressant drug halted not only the depression itself but also the loss of bone density.
The researchers were also able to describe the process connecting depression to the skeletal structure. They found that 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. The researchers were able to show that chronic treatment with a drug that blocks noradrenaline in the bone also blocks the detrimental influence of depression on the bone.
MEDICA.de; Source: The Hebrew University of Jerusalem