Depression - Is It Biological or Enviornmental

Depression touches many people’s lives, either through their own experiences or through a loved one, co-worker, or friend. Depression and MDD (major depressive disorder) are complex disorders and likely associated with a number of causes including the effects of multiple genes in combined with environmental and lifestyle factors (Verbeek et al, 2014).

There has been much debate over the years in the attempt to determine a cause of depression, be it biological or cognitive. Factors such as serotonin and the serotonin transporter gene, hormone imbalances, and heritability indicate a biological cause as the root of depression.

Serotonin and the Serotonin Transporter Gene

One of the main systems in the brain that has been studied most often in regards to depression is serotonin (Drevets, n.d.). Many of the drugs used to treat depression focus on the individual’s levels of serotonin. SRIs (serotonin reuptake inhibitors) and SSRIs (selective serotonin reuptake inhibitors) are often implimented in the treatment of depression. According to Drevets (n.d.), these types of medications increase the transmission of serotonin to some receptors by blocking the re-uptake of that serotonin into the cells that release it. Serotonin levels and the serotonin system itself has been shown to play a role in coping with stress and regulating emotional behavior in general (Drevets, n.d.). If an individual suffers from deficiencies in the serotonin system or in their serotonin levels, it can affect their reaction to stressful situations as well as their response to depression treatments.

Knowing that if you have an impairment in the system that could be caused by a number of factors including a genetic mutation (Drevets, n.d.), it could cause certain treatments to not be effective is an important factor in determining the best treatment for one suffering from depression. Many individuals who suffer from depression have found treatments using medications that target serotonin levels, such as SSRIs, work well for them though that is not the case for everyone. Medical professionals will often prescribe a combined treatment for individuals suffering from depression. According to Howland (2010), a combination of medications that target serotonin (such as Prozac) used in conjunction with medications that target regulation of the HPA axis hormones (such as metyrapone) have shown an increased response to SSRIs alone.

Stress and depression have been known to go hand in hand. The debate has often been which comes first, depression or stress. Recently it has been found that there is a genotype (5-HTTLPR) of the serotonin transporter gene that moderates the association between depression and later stress (Starr, Hammen, Brennan, & Najman, 2012). This suggests that depression can be a predictor for later stress. The connection between stress, depression, and the 5-HHTLPR is reciprocatory. Individuals in a