Depression is a prevalent and debilitating mental health disorder. Experts in the field estimate that it affects more than 21 million of America’s adults each year. However, youth are not exempt. The same specialists noted that 3.7 million youths between the ages of 12 and 17 could be affected. There’s a good chance that this dark figure is significantly higher because many people with symptoms don’t seek help.
Researchers have scientifically scrutinized depression for decades. Its causes and contributing factors are multifaceted with genetics being one of the prominent elements in this complex equation. Is there a relationship between genetics and depression? What is the genes’ role in its development? How do environmental and psychological factors contribute to this complex mental illness?
What Is Depression?
Before delving into the genetic aspects of depression, it’s essential to clearly understand what depression is. Depression, often called major depressive disorder (MDD), is a severe mental health condition. Psychiatrists determine that depression expresses itself in feelings of hopelessness, ongoing sadness, and a lack of interest or pleasure in activities you might have previously enjoyed. Individuals with depression may experience various physical and emotional symptoms, including changes in sleep patterns, appetite, energy levels, and concentration.
It’s interesting to note that depression expresses itself differently in individuals. While one person may find that they have no appetite at all, you may be on the exact opposite end of the spectrum and overeat. Similarly, some people with severe depression find that they cannot get out of bed. Others are unable to sleep and will stay awake for most of the night. Besides that, you might also find a shift in sleeping patterns. Daylight sleep may be preferable to nighttime rest.
There’s little doubt that depression significantly impacts everyday life, relationships, and overall well-being. Moreover, there’s a chance that it will have severe and ongoing consequences if left untreated. Since so many people suffer from the condition, researchers are now exploring whether genetics plays a role in its development.
The Genetic Component of Depression
Depression, like many other complex disorders, results from a combination of factors. At this time, doctors believe it includes genetic, environmental, and psychological factors. Genetic predisposition or susceptibility to depression has been the focus of various studies. For example, a review of family histories has shown that there’s a 20% to 30% chance of inheriting the traits for developing major depression.
Researchers have used twin and family studies to explore the heritability of depression, aiming to determine the extent to which genetics contribute to its development.
Twin Studies
Twin studies, a common approach in genetics, have provided valuable insights into the genetic component of depression. Identical twins share 100% of their genetic material. In contrast, non-identical twins share approximately 50% of their genes. By comparing the rates of depression in identical and non-identical twins, researchers can estimate the heritability of the disorder.
Twin studies have consistently shown that identical twins are more likely to share depression if one is affected than non-identical twins. Experts found that susceptibility is at about 50%. This number suggests that there’s a significant genetic component in the development of depression. However, it’s critical to mention that these studies also indicate that genetics is not the sole factor; environmental elements are also at play.
Family Studies
Family studies are another method used to investigate the genetic component of depression. They examine the occurrence of depression within families. These studies explore the rates of depression among first-degree relatives, such as parents and siblings, of individuals with depression. If depression has a strong genetic basis, it should be more common in families with a history of the disorder.
Family studies have provided evidence of a genetic link to depression. One study focused on 11,200 children from 9,462 families. Researchers discovered that the risk of developing depression went up significantly if the child’s family could trace two generations affected by depression. This finding further supports the idea that genetics plays a role in the likelihood of developing depression.
A Closer Look at an Identified Genetic Marker
Advances in genetics have allowed researchers to explore specific genetic markers associated with depression. They narrowed down involved genes to involve the serotonin transporter gene (5-HTTLPR).
This particular gene is involved in regulating serotonin, a neurotransmitter associated with mood. You may have heard that eating healthy, living healthy, and meditating can increase serotonin levels. In the body, it is the link between the central nervous system and the peripheral nervous system. Research has shown that individuals with certain variations of this gene may be more susceptible to depression, especially when exposed to adverse life events. However, it’s important to note that the relationship between this gene and depression is not straightforward, and it interacts with environmental factors.
The Role of Environmental Factors
While genetics plays a role in the development of depression, it is crucial to acknowledge the significance of environmental factors. Depression is not solely determined by genetic makeup; life experiences, stressors, and environmental conditions also influence it. In fact, there’s considerable research that’s looking to show how environmental factors affect the development of depression in someone who is at higher risk of developing it.
Examples are stressful life events, such as losing a loved one, job-related stress, or traumatic experiences. They can affect anyone and may trigger depression in susceptible individuals. That said, even those with a genetic predisposition to depression may not develop the disorder unless they experience such stressors. Even then, it does not follow inevitably that the person will develop the condition. Therefore, don’t consider one individual’s grief to be a sign of depression. While both can look very similar, grief is a temporary event that tends to come at you in waves. Depression is more permanent and consistently present.
Another area of concern is an individual’s childhood. Early life experiences and childhood adversity have been linked to an increased risk of depression in adulthood. Childhood trauma, neglect, or abuse can impact brain development and alter the expression of genes. These changes can increase susceptibility to depression in later life. That said, it is not well understood how much later depression may develop. Childhood adversity can cause depression in the teen years or much later.
Moreover, there are socioeconomic factors. These involve someone’s income, education, and access to healthcare. Individuals facing socioeconomic disadvantages are more likely to experience depression. However, even here, there are variables. A lack of income is not always felt as strongly by a single person as it is by the head of a household with people depending on them. While not directly related to genetics, these factors interact with genetic predispositions, highlighting the complex nature of depression’s causation.
The Role of Psychological Factors
In addition to genetics and environmental factors, experts have identified psychological factors as a possible catalyst for the development of depression. They mention negative thought patterns, low self-esteem, and a history of other mental health issues. As a result, there’s a school of thought that connects these psychological factors as interacting with genetic vulnerabilities.
What Does It All Mean for Treatment and Prevention?
Understanding the genetic component of depression has important implications for its treatment and prevention. While individuals with a family history of depression or known genetic vulnerabilities may be at increased risk, it’s important to remember that one’s genetics do not predetermine depression.
Having said that, for families with an increased susceptibility to depression, early intervention is critical. Identifying individuals with genetic susceptibility to depression can allow for intervention as early as childhood. Recognizing the risk factors and providing support and treatment would then mitigate the development and severity of the disorder.
Besides that, the knowledge of a genetic risk factor can lead to more targeted prevention strategies. If you know that your family history involves depression, you are far more likely to look for symptoms in yourself. Moreover, you may notice them in older or younger adults who share your genetics.
Beware Logical Fallacies and the Development of Stigma
There’s still a stigma attached to the development of mood disorders. Considered a mental illness, individuals typically do not want to disclose them – not even to family doctors. Doctors who have treated multiple members of a family must be vigilant not to assume that another member has the condition. Diagnosis and treatment have to be completely individualized.
Women, in particular, are at a higher risk of being diagnosed with depression even though their symptoms indicated another health condition. Specialists found that vitamin deficiencies, anemia, and hypothyroidism may express with the same symptoms as depression. In fact, depression may actually become a symptom itself.
A well-rounded physical exam is therefore highly advisable before jumping to conclusions. For some doctors, even psychiatrists, a complete physical with bloodwork is a requirement before beginning the treatment of possible psychiatric conditions. While it may feel inconvenient for the individual suffering from symptoms of depression, it is a good idea to rule out other conditions.
National Depression Hotline
If you or someone you know is struggling with depression, the National Depression Hotline can help. You don’t have to feel sad, out of sorts, or uncontrolled. Our trained professionals can provide resources for additional help. When you call, you can talk to someone and remain anonymous. You can call to have a listening ear, or you can call to find a therapist in your area.
Give us a call, or check out our website, and let us help you get back to feeling like your true self.
