Can Genetics Affect My Depression Risk?
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Researchers haven’t been able to isolate a single, clear-cut cause of major depression that applies to every person in every case. As with many other mental health conditions, depression likely develops due to a complex combination of factors that can vary significantly from person to person. That said, most experts agree that there is at least some genetic component to this illness.
See below to learn about this link between depression and genetics, other potential contributing causes of depression, and what this may mean for you.
What is depression, or major depressive disorder?
Depression, otherwise known as major depression or major depressive disorder (MDD), is a type of mood disorder that can affect children, teenagers, and adults. According to the National Institute of Mental Health, around 8% of U.S. adults will experience at least one depressive episode in their lifetime, making it one of the most common mental illnesses today. However, just because it’s relatively common doesn’t mean it’s not serious.
While their severity can differ from individual to individual, psychiatric disorders like major depression and anxiety disorders have the potential to cause considerable distress; significantly hinder daily functioning, work, and relationships; and harm well-being overall. That’s why learning to recognize the symptoms can be important, so you can seek treatment if you notice them in yourself.
Common depressive symptoms include but are not limited to:
Persistent sadness.
A sense of emptiness, hopelessness, or worthlessness.
A loss of interest in activities once enjoyed.
Significant changes in sleeping patterns.
Significant changes in appetite or eating habits.
Fatigue or low energy.
Difficulty concentrating.
Thoughts of self-harm or suicide.
Note that certain symptoms of depression must last for at least two weeks and interfere with functioning in order for a clinical diagnosis like major depressive disorder to be considered.
Three key risk factors
There is debate among many researchers about the precise causes of depression because isolating just one is often difficult. Today, there are generally three main schools of thought based on genetic testing and studies of other mammals, two of which support potential links between depression and genetics and one that focuses on nongenetic causes like environmental influences.
Stressful or traumatic life experiences
One theory is that depression can result from the stress or even psychological trauma caused by certain life events. This could explain why depression can develop in some people after they go through a breakup, lose a job, lose a loved one, or experience sexual abuse or assault, for example.
However, many people seem to experience depression without a clear inciting event like these. Additionally, some people develop depression after events like those listed above while others don't — a phenomenon documented even in cases of twins with common experiences. That’s why many believe there is more to depression than just how a person reacts to difficult life changes, extreme stress, or emotional trauma.
It’s also worth considering statistics about post-traumatic stress disorder (PTSD) and depression. PTSD can only develop after a person has experienced a traumatic event of some kind. Research indicates that the odds of a person living with PTSD developing depression are three to five times higher than for someone without PTSD. It’s another piece of evidence that reflects that life experiences can sometimes play a role in the development of depression — but since the comorbidity is not 100% for these two disorders, other factors are also likely at play.
A hormone or neurotransmitter imbalance
Another theory is that depression is caused by neurological structure or functioning on a cellular level. For example, it could be an imbalance of certain brain chemicals called neurotransmitters, which might sometimes be the result of genetic makeup — just like high blood pressure and other often-inherited conditions. Neurotransmitters are chemicals that impact mood as well as various physiological functions.
One called serotonin seems to be crucial to the neurological experience of depression. Serotonin affects feelings related to contentment as well as sleep-wake cycles, so insufficient amounts of it could explain some of the emotional and physical symptoms of depression. This imbalance may be because the body is not creating enough serotonin or because serotonin doesn't stick around long enough to be used appropriately, either due to insufficient serotonin receptors or the receptors not working like they're supposed to.
These conditions can be caused by drug or alcohol misuse or by the inheritance of certain genes linked to brain development. The latter would explain why depression often seems to run in families — with some sources citing a possible heritability factor as high as 50% — and also why some people experience depression without an obvious environmental cause. It’s also possible that genetics could cause malfunctions in the pituitary gland’s release of adrenocorticotropic hormones. Either way, genetics may play a significant part.
A combination of the two
The final leading theory is a combination of the first two. It posits that some people may have a genetic predisposition to depression because they’ve inherited imbalances of neurotransmitters or a neurological environment that could cause them, but that depression can then be brought about by stressful or traumatic life events. This theory would explain why some people are more likely to experience depression after such events and why depression can seem to run in families. However, it doesn't fully explain why some people can experience depression without any obvious contextual cause, so research on this topic is ongoing.
The implications of this potential link
The mental health awareness movement of the last several years has changed the way many people see mental illnesses like depression, and news about the potential genetic component has helped in this regard. For instance, it has helped many people understand that depression is an illness like any other and that it has nothing to do with a person’s willpower or character. Although some stigma still persists, many now view depression more as the medical disorder it is rather than as any type of personal shortcoming.
The idea of depression as a genetic disorder resulting from different genes also has implications in terms of treatment options. Knowing that you have a family history of close relatives with depression can allow you to be on the lookout for symptoms in yourself so that, if you ever notice them, you can receive treatment from healthcare providers right away.
Early diagnosis can make a significant difference in a person’s experience with a condition like depression because it can worsen over time if left untreated. For example, people with depression tend to have a higher risk of developing a substance use disorder (formerly known as “substance abuse”) and a higher risk of self-harming behaviors, as mentioned above.
However, just because one of your first-degree relatives has depression doesn’t necessarily mean you’ll develop the condition, too. Depression is a complex disorder with many factors that may contribute to its onset. This also means that someone who does not have a family history of depression can still develop it. Some conditions may be entirely genetic, but depression doesn't seem to be one of them. In other words, knowing about a family history of depression can simply be a useful piece of information that empowers you to keep a closer eye on your mental health.
Getting help and finding support
Armed with the knowledge that depression and anxiety are illnesses that often have a genetic component and can develop in anyone, individuals may be better able to overcome the stigma around reaching out for help. If you're experiencing symptoms of depression, seeking professional help is recommended. Effective ways to treat depression are available.
Some form of talk therapy — cognitive behavioral therapy (CBT) in particular — is perhaps the most commonly recommended type of treatment for depression, with one network meta-analysis indicating its effectiveness for many people. Other types of therapy may be considered as well, including electroconvulsive therapy (ECT). Your healthcare provider may also recommend medication in addition to therapy, depending on your unique circumstances and health. Finally, certain lifestyle changes, such as exercising regularly and eating nutritious foods, are often part of treatment as well.
Online therapy
If you’re interested in seeking the support of a therapist for depression symptoms, online therapy may be a good place to start. Many people find it to be a less intimidating and more convenient way to receive care. With a platform like BetterHelp, for instance, you can get matched with a licensed therapist by simply filling out a questionnaire. You can then meet with them via phone call, video chat, or in-app messaging to address the challenges you may be facing. Research suggests that online therapy may even be more effective for treating depression than in-person sessions, so it’s worth considering if you face barriers to in-person care or would simply prefer a virtual format.
Takeaway
Does genetics play a role in depression?
Yes, genetics can play a role in depression. One study from 2011 states that research has consistently shown that there is a hereditary component to depression, meaning that individuals with a family history of depression may be at a higher risk of developing the condition themselves. However, it may be important to understand that genetics is just one of many factors that contribute to this disorder.
Multiple genes are believed to be involved in the development of this disorder, and it's likely that a combination of hereditary, environmental, and other factors contributes to an individual's susceptibility to the disorder. Environmental factors such as trauma, chronic stress, or life events can also interact with predispositions to influence the risk of depression.
What are the factors of MDD?
The genetics of this disorder are complex and involve multiple factors, each with a relatively small effect. Researchers have been studying its basis to identify specific pathways that may contribute to the risk of developing the disorder. Here are some key points:
Polygenic nature: Depression is considered a polygenic disorder, meaning that it is influenced by multiple factors. No single pathway is responsible for causing this; instead, it involves the interaction of many genes with each other and with environmental factors.
Serotonin and neurotransmitters: Some pathways involved in the management of neurotransmitters, such as serotonin, have been implicated. Serotonin is a neurotransmitter that plays a role in mood management, and variations related to serotonin function have been associated with an increased susceptibility to depression.
Brain-derived neurotrophic factor (BDNF): BDNF is a protein that may play a role in the growth, development, and maintenance of nerve cells. Changes in the BDNF have been linked to depression, as lower levels of BDNF are associated with decreased neuroplasticity, which may contribute to the development of depressive symptoms.
Hormonal management: These are involved in the management of the stress response and the hypothalamic-pituitary-adrenal (HPA) axis, which plays a role in the body's reaction to stress.
Inflammatory pathways: There is growing evidence suggesting a link between inflammation and depression. Pathways involved in the immune system or inflammatory responses may contribute to the risk of developing this disorder.
Vulnerability and environmental factors: It's important to note that these factors alone do not determine whether someone will develop this condition. Environmental factors, such as early life stress, trauma, or chronic stress, interact with hereditary vulnerabilities, influencing the likelihood of developing it.
Is depression epigenetic?
Both genetic and epigenetic factors can contribute to depression, and they interact in complex ways. The interaction between genetic and epigenetic factors is intricate. Environmental stressors or experiences can lead to epigenetic modifications that influence expression, potentially contributing to its development. For example, chronic stress may induce changes in the epigenetic management involved in stress responses or mood management.
Research in this area is ongoing, and scientists are working to understand the specific epigenetic modifications associated with this condition. The field of epigenetics adds a layer of complexity to our understanding of how hereditary factors and the environment interact to influence mental health.
What are five examples of hereditary factors?
While it's important to note that depression is a complex condition influenced by both genetic and environmental factors, here are five examples of factors that have been implicated:
Serotonin transporter: Variations in the serotonin transporter, which codes for the serotonin transporter protein, have been associated with an increased risk of this condition. The serotonin transporter is involved in the reuptake of serotonin, a neurotransmitter that plays a key role in mood management.
Brain-derived neurotrophic factor (BDNF): BDNF is a protein that supports the growth and maintenance of nerve cells in the brain. Changes in the BDNF have been linked to alterations in neuroplasticity, and lower levels of BDNF are associated with an increased risk.
Dopamine receptor: Dopamine is another neurotransmitter involved in mood management, reward, and pleasure. Variations in genes that code for dopamine receptors, such as DRD2 and DRD4, have been studied in relation to depression susceptibility.
Catechol-O-methyltransferase (COMT): The COMT is involved in the breakdown of neurotransmitters like dopamine and norepinephrine. Variations in COMT have been associated with differences in stress response and emotional management, potentially influencing the risk of depression.
Hypothalamus-pituitary-adrenal (HPA) axis: The HPA axis is a key component of the body's stress response system, and dysregulation of the HPA axis has been implicated in this condition. Genes involved in the management of the HPA axis, such as the corticotropin-releasing hormone (CRH), have been studied in relation to depression.
Are mental health conditions genetic?
Yes, there is evidence to suggest that mental health conditions can have a genetic component. Many mental health disorders, including depression, bipolar disorder, schizophrenia, anxiety disorders, and other mood disorders, are believed to result from a combination of genetic and environmental factors, among others. Bipolar disorder has a particularly high genetic risk, with genetic factors accounting for approximately 80% of the cause.
Does depression alter DNA?
Yes, chronic stress can potentially lead to changes in DNA through a process known as epigenetics. Epigenetics refers to modifications to the DNA molecule or associated proteins that can influence expression without changing the underlying DNA sequence. These modifications can be influenced by environmental factors, including stress and experiences associated with mental health conditions.
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