Living with depression is a struggle. It can cause persistent feelings of sadness, anxiety, or emptiness, and often causes those struggling with it to lose interest in the things they used to enjoy. It is only natural that these people, and their doctors, want to know what causes depression, with many believing it to be genetic.
What Research Says
There have been a number of studies over the years which have attempted to prove whether or not depression is genetic. These studies have specifically looked at familial history of depression and the occurence of depression among twins.
Family Studies
Studies regarding families look at the history of depression in family members, with most studying three generations. They also compare the rate of depression among siblings. Findings from the Adolescent Brain Cognitive Development study show that offspring with no familial history of depression have the lowest risk of developing depression. On the other hand, offspring with both a parent and grandparent who have suffered from depression have the highest risk of developing depression. These people are estimated to have a 2–3 times greater risk of developing depression than someone with no familial history of depression. This points to genetics at least being a factor when it comes to the likelihood that a person will have depression at some point in their life.
Twin Studies
Twins are crucial when it comes to determining if any disease or condition is genetic. Identical twins share 100% of their genes, meaning that if one of them has a disease, and it is genetic, then the other twin will have it as well. Studies have shown that when depression is present in one twin, it is not always present in the other. However, the other twin does have a much higher risk of developing depression. These findings point to genetics playing a role in the development of depression, but not being the only factor at play.
Gene Variants
There are a number of gene variants which have been found to have a link to depression. First, there are genes which affect neurotransmitters, such as the gene SLC6A4. This gene controls how serotonin is transported through the brain. Certain variants of this gene are believed to lower the amount of serotonin in the brain, contributing to the development of depression.
Next, there are genes which affect circadian rhythm. It has long been understood that disruption of circadian rhythm increases a person’s risk of developing depression. Variants of genes such as Per2, CK1δ, Per3, CLOCK, and CK1ε can cause people to have a disrupted circadian rhythm or to have a diurnal preference.
Finally, there are variants of genes controlling synaptic plasticity, which is the process that allows neurons to communicate and change their connections based on past experiences. Variants of the genes ZNF804A rs7603001, CHL1 rs2133402, and GluR7 have all been shown to disrupt synaptic plasticity. When synaptic plasticity is dysfunctional, an individual has a much higher risk of developing depression.
Is Depression Inherited?
Depression itself is not inherited, but the risk of developing depression is. Most scientists believe that depression is 40-50 % genetic, and lifestyle and coping mechanisms can help prevent depression from manifesting. This means that just because a person has a familial history of depression, does not mean they will become depressed at some point in life. However, these people should be on the lookout for signs of depression in themselves.
Factors that Contributed to Depression
Besides genetics, there are multiple factors which contribute to a person developing depression. These include:
- Lifestyle: Low physical activity, poor nutrition, and excessive use of alcohol and drugs can all contribute to depression.
- Stressful Experiences: The death of a loved one, unemployment, traumatic events, financial problems, or anything that causes major, negative life changes can contribute to depression
- Medical Issues: People with serious illnesses such as cancer, a stroke, or diabetes are at higher risk of developing depression. Additionally, certain medications can contribute to depression.
The more of these a person experiences, the higher risk they have of developing depression. Luckily, the risks from lifestyle can be mitigated by eating well, exercising, and avoiding drugs and alcohol. The risks from stressful experiences and medical issues can be mitigated with the use of depression coping mechanisms and therapy to accept one’s circumstances.
Seeking Treatment
Fortunately, depression can be treated. If your child is experiencing depression, you should enroll them in a teen depression treatment program immediately. This program will focus on gradual relief from symptoms. Through the use of cognitive behavioral therapy and coping mechanisms, your child can begin to heal. Additionally, they will learn how to live a lifestyle that combats depression. With enough care, attention, and patience, your child can return to living a vibrant life free from the shadow of depression.