Is Depression Genetic? Experts Explain the Causes of Depression

Is depression genetic, or is it brought on by life circumstances? The answer is more nuanced than a simple yes or no. Keep reading to learn more.

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When we think about genetics, we think about things like eye color, hair color, and hair texture. But did you know that genes also play a role in our mental health? Many mental health conditions can be influenced by the genes we inherit.

Major depressive disorder (also referred to as “clinical depression” or simply “depression”) is a mood disorder characterized by ongoing low mood, hopelessness, emptiness, and lack of motivation — but is depression genetic?

It’s one of the most common mental health disorders, affecting over 332 million people worldwide. Statistically speaking, it’s likely that a large percentage of these people have depression as a result of (or at least in part due to) genetics. But how much of depression is genetic, and how much comes from your environment?

Is depression genetic or environmental?

Depression is caused by various factors, both genetic and environmental. “Depression, as well as many psychiatric illnesses, seems to have a familial link,” says Kathleen Douglass, LCPC, a Charlie Health Primary Therapist. “We have not yet identified a specific ‘depression gene,’ but depression does tend to run in families.”

With some genetic disorders, scientists have been able to pinpoint the exact gene that causes them. These are known as single-gene disorders. In these conditions, researchers know the specific affected gene that results in a disorder, such as cystic fibrosis or Huntington’s disease, for example.   

However, as Douglass mentions, there is no known specific gene directly related to depression that has been found. It’s likely that many genes interact and play a role in genetic predisposition to depression. Epigenetics plays a role, too. This refers to how your environment and life experiences can influence how your genes are expressed (or turned on and off). 

Here are some things we know about the genetic link:

• If you have an immediate relative (parent or sibling) with depression, you have a higher risk of developing depression, too. 
• The genetic risk for developing depression is even higher if multiple family members have depression.
• The heritability of depression is about 40%, which means that 40% of the differences in who develops depression can be explained by genetics. Environmental factors and life experiences shape the remaining risk.

To clarify, just because a family member has depression, it does not mean you are guaranteed to have it, too. “Genetics do not ensure you will inherit depression, but they increase the likelihood that you could experience depressive episodes or that you would be more susceptible to depression than those people who have no genetic link,” Douglass says. 

Environmental risk factors for depression

Environmental risk factors play a major role in the development of depression, too. You can have depression even without genetic factors and a family history of mental illness. 

Many people develop depression primarily due to life experiences, stressors, or health-related factors rather than inherited genetic risk alone. These include:

1. Adverse childhood experiences

Having adverse childhood experiences (ACEs) — such as losing a parent, witnessing violence in your home, or growing up in a home where someone had a substance use disorder — increases your risk of developing depression. Research shows that having one ACE increases your risk by 50%, and experiencing multiple ACEs may further increase risk. 

2. Childhood trauma

Similar to ACEs, childhood trauma can result in a higher risk of developing depression, along with other mental health conditions. Childhood trauma affects your brain and can lead to a higher risk of depressive disorders, research shows. Childhood trauma could include experiencing sexual, physical, verbal abuse, or child neglect. Any life-threatening instances — like a school shooting, mass violence, or a natural disaster — are also examples of childhood trauma. 

3. More recent trauma

Experiencing trauma at any point in your life, including adulthood, increases the risk of depression — especially if someone develops post-traumatic stress disorder (PTSD) as a result of the trauma. People with PTSD are around three to five times more likely to develop depression. 

4. Chronic health conditions

Having a chronic health condition, such as diabetes, cancer, Parkinson’s, or a cardiovascular condition, can increase depression risk. 

5. Loneliness

Loneliness and social isolation can result in depressive symptoms, and older adults are especially at risk. Research shows loneliness and depression can (and do) feed off each other. 

6. Having another psychiatric disorder

A diagnosis of another psychiatric disorder (or disorders) significantly increases the risk of depression. Mental health conditions put a strain on your emotions, quality of life, and daily functioning, making depressive symptoms more likely to develop over time. For example, research suggests a whopping 20-fold risk of developing depression with the new onset of anxiety disorders, especially panic disorder or generalized anxiety disorder (GAD).

7. Traumatic brain injury (TBI)

Research suggests that people who have experienced a TBI are twice as likely to develop depressive symptoms, and that around 13% of people who’ve suffered from a TBI will develop depression. 

Are other depressive disorders genetic? 

Other depressive disorders outside of major depressive disorder have a genetic factor, too. While the degree of heritability varies by disorder, research consistently shows that family history increases risk across different types of depressive disorders.

Is postpartum depression genetic?

There is a genetic component to postpartum depression (PPD), and research shows that if you have a first-degree family member (mother or sister) who had postpartum depression, you have an increased risk (2.5 times more likely) of developing PPD yourself.

Genetics isn’t the only contributor, though. “There are many other factors that can contribute to PPD, which include sleep deprivation that is common in new moms, the recovery time from the actual birth, and the drastic life changes that inevitably happen when you add a new baby to your routine,” Douglass says.

Research suggests other risk factors for PPD include:

• Low social support
• Low spousal support
• History of depression
• Having a negative birth experience
• Having a pre-term or low birth weight baby

Is seasonal depression genetic?

Seasonal depression, AKA seasonal affective disorder (SAD), also has a genetic component, according to family and twin studies.

It’s estimated that 15% of people with SAD have a first-degree relative who has also had SAD. Furthermore, anywhere from 25 to 67% of people with SAD have at least one relative with a psychological disorder in general, such as major depressive disorder. Scientists have found a link between certain “clock genes” related to your circadian rhythm (your internal body clock) and seasonal depression. 

However, environmental factors have a very strong influence on the development of SAD, Douglass says, since it frequently develops during the fall and winter months, when there are fewer hours of daylight and less time spent outside. 

Is bipolar depression genetic?

Yes, there is a strong genetic link with bipolar depression, AKA bipolar disorder. In fact, this psychiatric disorder is one of the most heritable, with 60 to 80% heritability. Someone who has a first-degree relative with bipolar disorder has a 10-fold increased risk, compared to the general population. 

Researchers have identified 36 genes linked to bipolar disorder, including some that may be connected to certain bipolar disorder subtypes. However, environmental factors still play a role, too, Douglass says. Other than genetic risk factors, some other factors include:

• Trauma 
• Negative stressful life events
• Physical, sexual, or emotional abuse
• Substance use 

Depression treatment and genetics

Whether you are dealing with major depression, SAD, PDD, or bipolar disorder, help is available. “​​The important thing here is that all of these illnesses are treatable and manageable to a large extent,” Douglass says.

Depression treatment often includes two components: therapy and medication. Therapy helps you address unhealthy and unhelpful thoughts and behaviors. For example, cognitive behavioral therapy (CBT) helps you learn how your thoughts, feelings, and behaviors are interconnected, empowering you to replace negative thought patterns with more positive ones. Another modality, dialectical behavior therapy (DBT), teaches you how to cope with distress in a healthy way and regulate your emotions. 

For people with moderate to severe depression, a provider might recommend a psychiatric medication as part of the treatment plan. Antidepressants, such as selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs), act on brain chemicals related to mood to help relieve depression symptoms. SSRIs and SNRIs are often the first-line medication choices, but other types of antidepressants are available, too. If you have bipolar disorder, treatment typically involves mood stabilizers instead of antidepressants.

How Charlie Health can help

If you or a loved one is struggling with depression, Charlie Health is here to help. Charlie Health’s virtual Intensive Outpatient Program (IOP) provides more than once-weekly mental health treatment for dealing with serious mental health conditions, including mood disorders like major depressive disorder, bipolar disorder, seasonal affective disorder, and postpartum depression. Our expert clinicians incorporate evidence-based care into individual counseling, family therapy, group sessions, and medication management, as needed. With treatment, managing depression is possible. Fill out the form below or give us a call to start healing today.