Do These Genes Make My NPY Count Look Big?

How could genetics affect depression? Well, in the study presented in my last post, a specific gene seemed correlated with a monoamine deficiency, which seems to be involved in depression. It has also been supposed that due to the differences in scans of the brains of the depressed and the non-depressed, the development of the brain structures affected could be involved.  Medicine has barely begun to research what genes are involved in depression and for what reason. What is known is that people with a relative with major depression are two to three times as likely to become depressed. This is not a statistic generated by that person's proximity to depression. In separated identical twins, there is a 40-50% risk of one twin developing major depression if the other twin has already done so.

Many studies of genetic predisposition of depression refer to the molecule neuropeptide Y (NPY). Studies have shown that people with less of this molecule have stronger brain responses to stressors. This sort of study identifies a factor that could contribute to the cause of depression that is completely unrelated to the monoamine theory, further convincing me that the cause of depression is multifaceted. This study also pointed out that those lacking NPY were "overrepresented in a population diagnosed with major depressive disorder," indicating a correlation between the two. However, sensitivity to stress can be a risk factor for more than just depression. In fact, this may be a connection between anxiety and depression, two disorders that are treated in similar ways and can coincide. Also, NPY has been shown to induce eating in animals injected with it. The hormone Leptin, which stimulates weight loss, decreases the output of NPY by the hypothalamus. This is especially interesting because depression is sometimes, but not always, accompanied by weight loss.

This article discusses, quite aptly in my opinion, that though the depression gene research is only in it's early stages, the prevalence of this disorder will inevitably lead to more and more research on the subject. An understanding of the genetic factors of depression would yield to a better understanding of the biology of depression generally and perhaps even of some of the environmental factors. The more we know, the better our treatments can become.

Digital image. Mayo Clinic. Web. 22 Mar. 2012. <http://www.mayoclinic.com/health/medical/IM00356>.

"Genetic Factors of Depression." Livestrong. Web. 22 Mar. 2012. <http://www.livestrong.com/article/102769-genetic-factors-depression/>.

"Natural Born Pessimist: Some People Are Genetically Programmed to Be Depressed, Scientists Say." Daily Mail Online. Feb. 2011. Web. 22 Mar. 2012. <http://www.dailymail.co.uk/sciencetech/article-1354811/Some-people-genetically-programmed-depressed-scientists-say.html>.

Zhou, Zhifeng. "Genetic Variation in Human NPY Expression Affects Stress Response and Emotion." Nature.com. Nature Publishing Group. Web. 22 Mar. 2012. <http://www.nature.com/nature/journal/v452/n7187/abs/nature06858.html>.

"Emotion Processing, Major Depression, and Functional Genetic Variation of Neuropeptide Y." Archives of General Psychiatry, a Monthly Peer-reviewed Medical Journal Published by AMA. Feb. 2011. Web. 22 Mar. 2012. <http://archpsyc.ama-assn.org/cgi/content/abstract/68/2/158>.

 "Study Closes In On Genes That May Predispose Some People To Severe Depression." ScienceDaily. ScienceDaily, 01 Feb. 2007. Web. 22 Mar. 2012. <http://www.sciencedaily.com/releases/2007/02/070201082225.htm>.

 "Neuropeptide Y." TheFreeDictionary.com. Web. 22 Mar. 2012. <http://medical-dictionary.thefreedictionary.com/neuropeptide Y>.