Is Depression Genetic or Environmental?

Studies on depression have shown that there is evidence that depression is genetic based, in particular the bipolar disorder or manic depression as it is referred to.  Still, people continue to wonder, is depression genetic?  Actually many believe that depression has more to do with thought processes, behavioral patterns and interpersonal relationships. For these reasons, it does appear to get passed down in families causing many to ask is depression genetic? However, it is also very likely that when a close relative in the family, like a parent suffers from depression or other mental illness, the basic behavior model is learned from that person.  Thus it appears to many that depression is environmental in nature rather than that depression is genetic or hereditary.  It is likely the case that both genetic and environmental factors play a role in depressive mental illness.

The experts on depression claim that to some extent being clinically depressed is genetic. Or rather, the vulnerability to depression is inherited. It does not mean that everyone who has a family member suffering from clinical depression is destined to become depressed or need to seek therapy.

Is it true? - Is depression genetic?

Research on the subject of mental illness and genetic depression has shown that some individuals have a greater vulnerability to the disease than others. People, who have a near relative like a parent or sibling with major depression problems, are three times more likely to inherit depression than people who have not had a close family member face this problem. Because close relatives of people with clinical depression are vulnerable to developing the condition, it strongly suggests depression is genetic.

Bipolar disorder or manic-depressive mental illness has been known to have a strong genetic influence on people. This is a brain disorder that causes unusual mood swings between extremely happy and extremely irritable moods. The overjoyed state is called manic and the sad, depressed state is called depressive. Studies trying to find whether there is an environmental answer or is depression genetic show that of the people diagnosed with bipolar disorder, approximately 50 percent have had a history of a parent with clinical depression. When a parent is manic-depressive, the child has a 25 percent chance of being clinically depressed. If both parents have bipolar disorder, then the odds of the child developing the same problem increase considerably, anywhere from 50 to 75 percent. Further, the siblings of a person with bipolar disorder are anywhere from 8 to 18 times more likely to develop the same problem than people without siblings.

Clinical Depression and Genetic Influence

Considerable research into the genetic influence of clinical depression has been done on identical twins that have the same genetic makeup. Studies show that when one twin becomes depressed, there is a 75 percent chance of the other twin also developing clinical depression. In the case of identical twins being raised apart from each other, there is a 67 percent chance of them both developing depression. Due to the high percentages, the implication is that genetic influence is extremely strong. Since the statistics do not exhibit a 100 percent trend, it has been inferred that other factors like childhood experiences, traumatic events, exposure to substance abuse and medical illness can influence the person’s vulnerability to clinical depression and other mental illness.

Studies on fraternal twins who have only 50 percent of the same genetic makeup, reveal, that the percentage of both twins developing depression is about 19 percent of the time. This rate is still higher than the rates for the general public, another pointer toward the fact that it may be hereditary.

Is Depression Genetic?

However, the jury is still out on the question - is depression genetic?  Simply because it does seem to run in families can argue as much for the case that depression is environmental or learned behavior as it does for the case that there is a genetic answer.