Experiment on Rats Solved the Mystery of Human Depression

One the new experiment on rats which was held in Jerusalem was solved the mystery of human Depression.  A team of Israeli scientists have experimented on rats to see how they cope with stress, and hope the study would contribute to understanding the cause of human depression and suicide.

Results of the study suggest that while exposure to stress in childhood increases the risk of depression and anxiety, as one might expect, exposure to stress in adolescence may actually provide protection against depression and suicidal behaviour later in life, a media report here said.

“This is the case even for adolescents who were genetically predisposed to suicide”, the lead researcher, Professor Gil Zalsman, deputy director and chief of the child psychiatry division of the Geha Mental Health Center and associate professor in psychiatry at Tel Aviv University’s Sackler School of Medicine, told the daily calling the finding “surprising”.

The study also revealed the differences in the responses to stress between rats with a genetic predisposition to depression, meaning they have hormonal and behavioural abnormalities that emulate those found in depressed humans, and rats without a “depression gene”.

The research carried out at a laboratory at Bar-Ilan University tested rats of the Wistar-Kyoto strain, which are genetically predisposed to depression, and Wistar rats, exposing them to different types of stress at different points in their life cycle.

The Wistar rats were the control group. The stress-inducing tests included being held overnight in a cage filled with wet sawdust, in one case, and in another, being forced to swim, the report said.

The study will be presented on Thursday, the final day of the 14th European Symposium for Suicide and Suicidal Behaviour, in Tel Aviv.

A third group of rats were exposed to a stimulation-rich environment after undergoing the stress tests during the equivalent of childhood recovered from the traumatic events. This indicated that the tendency toward suicidal behaviour as a result of exposure to stress is apparently reversible, Zalsman said.

Studies from the 1980s, of pairs of twins that committed suicide showed that the risk of the second twin committing suicide after the first twin ended his or her life was 11.3 per cent for identical twins, who share all their genetic material, and 1.8 per cent for fraternal twins, who do not. And a groundbreaking study led by Israeli scientist Avshalom Caspi and published in the July 2003 issue of Science showed that people with the “depression gene”, a short-allele variant of the 5-HTTLPR serotonin-transporter gene, are more vulnerable to stress.

Image Source: http://www.sxc.hu/photo/1097313