Recent study shows that depression is caused by not only chemical-shortage factor but also weak synaptic structure

A team of the Johns Hopkins University School of Medicine found that rats given Prozac did not merely experience a change in their brain chemistry but also grew new fibers in mood-critical areas. This finding suggests that depression reflects problem of fine neural structure and not just the brain chemistry. This in turn supports the emerging “network hypothesis” of mood.

Previously it was believed that depression mainly caused only by chemical factor. One of the old belief states that depression occurs because of the brain circuitry lack of neurotransmitter serotonin in key synapses decreasing mood-regulating neural signaling, causing depression. The recent study shows that mood disorder partly caused by weak synaptic structures caused by weak nerve and dead fibers, which interrupting the signaling process.

With such complex techniques, the team found that rats given Prozac grew more axons on serotonin-sensitive neurons in cortical and forebrain areas which crucial to mood regulating. According to Lijun Zhou, a researcher in neurosurgery, this change is “critical effect of serotonin anti-depressants” and could help to explain some successful anti-depressant therapy. This is in line with the other human studies, which show that drug and talk therapy when successful, raising the levels of neurotrophins - pervasive brain-growth chemicals. Any shortage of neurotropins may affect the structural weakening of neural-network circuits.

Thanks to this finding, now we can produce a richer understanding about depression, as well as more possibilities for therapy.