Is Depression Genetic? Understanding Biology And Mental Health

Researchers have made significant strides in understanding depression. It is now accepted and understood that depression is a mental illness, not a form of sadness or laziness. It can have emotional, mental, and physical impacts. For some, these symptoms directly result from a difference in brain chemistry, which may have a genetic component. 

Understanding the causes of depression may provide insight into how this condition could've developed for you or someone you love. However, regardless of the cause, depression is often highly treatable.

What causes depression? 

The causes of depression are still unclear. However, there is a chance of a genetic component. Still, life events and upbringing can also impact mental health. Not everyone with the same DNA or life events experiences depression, making it unique to individuals. 

There is no one cause for depression. A complex interplay of factors causes the disorder and manifests differently for each person. Examining the many possible causes of depression can help those in a community empathize with others and receive insight into the most effective treatment for themselves or those they love. 

Depression statistics

There have been hundreds of studies on depression and genetics, but the results may be contradictory in some cases. Below are a few studies to understand the potential connections between depression, family, and genetics. 

Who is most likely to have depression?

Women are statistically 1.7 times more likely to experience depression in general. This difference may be attributed to men's struggle to seek support due to stigmas surrounding mental healthcare. Reducing stigmas about expressing emotions can help men feel comfortable reaching out and getting help. 

Is depression hereditary? 

Twin studies are a common way of determining the role of genetics in any illness. Through such studies, scientists have determined a 40-50% heritability factor in depression. This result means that 50% of the cause of depression is related to non-genetic factors, such as environment or trauma, whereas 40% to 50% may be related to genetics. 

A 2011 study found that chromosome 3p25-26 may be responsible for severe, recurrent depression in families. However, this study does not necessarily explain the 50% heritability factor of mild to moderate depression. It may be that half of all cases of mild or moderate depression are solely genetic, while the other half is not genetic at all. It could also mean that each case of depression is caused by a 50/50 combo of genetic and environmental factors.

However, numbers indicate a slight difference in people who experience severe or recurrent depression. In these cases, the heritability factor is higher. However, this type of depression is rare, occurring in only about 3% to 5% of the general population.

How can genetics and healthcare shed insight into depression?

Researchers may be able to find clues about the causes of depression by looking at the links that genetics has with other diseases.

Chromosomal diseases 

Some diseases are chromosomal. That means they are caused when chromosome sections are missing, duplicated, or altered in some way. Down syndrome is an example of a chromosomal disease. Based on research, some may argue that severe or recurrent depression may also be considered a chromosomal abnormality.

Monogenic diseases 

Other diseases are known to be monogenic. Monogenic illnesses are caused by a defect or mutation in one specific gene, which causes it to stop working correctly. Some examples of monogenic illnesses are cystic fibrosis and sickle-cell anemia.

Multifactorial diseases 

Most diseases are multifactorial. These cannot be traced back to a single gene and are caused by multiple gene mutations in addition to environmental factors. These illnesses are the ones for which it can be challenging to find a cause or treatment that works for each individual. They include cancer, diabetes, and cardiovascular disease.

Depression and other mental illnesses like bipolar disorder may be multifactorial. There isn't one single depression gene. Researchers are still trying to find out which genes are responsible for depression. Depression-related genes may differ for different people, too. Further research is required into which genetic factors interact with the environment to lead to depression.

Inheriting genes 

Based on what science knows about genetics and illness, each person inherits genes from both parents that may predispose them to some illnesses, making them more likely to experience a condition. However, it may not be 100% likely for them to experience the condition, as recessive genes can sometimes take over, even if both parents have a dominant gene for a mental or physical health condition. 

For example, one person might have a genetic predisposition to heart disease. Having a predisposition doesn't ensure the person develops heart disease at any point. However, if they embrace a lifestyle with unhealthy behaviors, they may be more susceptible to it. Despite this, some people with unhealthy behaviors and predispositions do not develop diseases. 

This reasoning can also apply to mental illnesses. For example, a person may have two parents with diagnosed depression. They may feel mentally well and have a safe home life. However, after exposure to traumatic bullying, the individual starts to develop similar symptoms of depression as their parents. This event and a genetic predisposition led to a depressive episode for this fictional individual. 

Environmental factors

A combination of genetic and environmental factors causes depression. It can be beneficial to know which non-genetic factors may incite depression in someone who is genetically predisposed. Statistically, the following events and circumstances have proven links to depressive episodes:

• Childhood abuse or neglect
• Grief and loss (including losing a parent early in life)
• Divorce
• Financial insecurity 
• Social isolation
• Illness and chronic pain 
• Relationship conflicts

In some cases, a parent's depression may impact a child. If a parent unknowingly neglects or harms their child, these environmental factors may further predispose them to depression. Parents living with depression may also experience conflict with family members, which may lead to home stress for children. 

In addition, some parents with depression may lack the skills or the motivation to teach their children positive coping strategies to cope with stress. Children who don't see their children mirroring healthy coping mechanisms may struggle to adapt to emotional challenges and could be more at risk for depression. 

Genetics and disease

So what can we say about the link between depression and genetics based on these statistics? Not much. But we can find some clues about the causes of depression by looking at the links that genetics has with other diseases.

Some diseases are chromosomal. That means they are caused when sections of a chromosome are missing, duplicated, or altered in some way. Down's syndrome is an example of such a disorder. Based on recent research, you could argue that severe or recurrent depression may be considered a chromosomal abnormality as well.

Other diseases are known to be monogenic. That means they are caused by a defect or mutation in one specific gene which causes it to stop working correctly. Some examples of monogenic illnesses are cystic fibrosis and sickle-cell anemia.

However, most diseases are multifactorial. These cannot be traced back to a single gene. They are caused by multiple gene mutations, in addition to environmental factors. These illnesses are the ones for which it is difficult to find a cause or even a treatment that works for everyone. They include cancer, diabetes, and cardiovascular disease.

Depression and most other forms of mental illness are multifactorial. That means there is no single depression gene. We don't know exactly which genes are responsible for depression, as it seems to be different for different people. And we're still not sure about the extent to which genetic factors interact with the environment and "nurture" to lead to depression.

Based on what we know about genetics and illness, it seems likely that each person inherits a set of genes from both parents which may predispose them to some illnesses, making it more likely that they will experience a particular illness or disorder.

For example, one person might have a genetic predisposition to heart disease. This does not necessarily mean that they will endure a cardiac event. However, if they embrace a lifestyle with unhealthy behaviors, this can trigger the predisposition that already exists.

It's the same with mental illness, too.

For example, let's say your mom or dad has depression. You may be fine until your peers started bullying and harassing you at school one day. This event, combined with a genetic predisposition, can lead to a depressive episode.

Defensive factors against depression

Perhaps you have depression, and you worry that your children might inherit that trait. Or maybe you have a parent who is feeling depressed, and you wonder if that lingering sadness you feel might be the onset of a depressive episode. While you may be at greater risk, taking these steps can reduce that risk.

Educate yourself about the symptoms

Depression often starts as anxiety in young children. Be aware of signs of anxiety, such as nail biting or easy startling. If your child tends to worry obsessively, this can be a precursor to depression.

Notice especially if they make comments about not wanting to live anymore. This is a sign that they need help immediately. If you or a loved one are experiencing suicidal thoughts, reach out for help immediately. The National Suicide Prevention Lifeline can be reached at 988 and is available 24/7.

Learn strategies to manage stress

Develop an array of coping strategies, such as meditation, breathing exercises, and affirmations. Agree on a procedure for peacefully resolving conflicts. Teach these coping strategies to other families, especially to your children.

Connect with others

Make sure that you and your family have a strong support network. Spend time with friends. Encourage your children to foster meaningful friendships. Sign up for sports or join a local church or synagogue. Connecting with a support network will improve your mental health.

Exercise

Make sure everyone in the family has a daily exercise routine. Vigorous exercise releases feel-good endorphins in the brain which are a powerful antidote to depression.

Encourage healthy eating habits

Consuming too much sugar can have an immediate negative impact on mood. A diet high in vegetables can give your brain the nutrients it needs to function at full capacity. A healthy diet is one of the simplest ways that you can make sure you and your family can enjoy optimum physical and mental health.

Avoid drugs and alcohol

You might think these substances will make you feel better. But in the long run, using drugs or alcohol just creates dependency issues. It also can make the home environment feel unstable and unpredictable to any children that live there.

Seeking support for depression

It may be beneficial to turn to a doctor and/or a mental health professional for guidance. Online therapy is becoming an increasingly popular option for adults and teenagers seeking support for depressive symptoms. Through online platforms like BetterHelp, you can match with a qualified counselor within 48 hours, significantly shorter than the average time it takes to find a compatible in-person therapist. 

Online therapy is proving to be just as effective as in-person therapy for a number of mental health conditions. In a six-week randomized controlled trial involving 60 participants identified as experiencing symptoms of anxiety or depression, researchers created an experimental group in which received one online session weekly. Therapists used popular depression treatment approaches like cognitive behavioral therapy (CBT) and acceptance and commitment therapy (ACT) to support patients in achieving reduced symptoms during this time frame. At the end of the study, the therapist-guided online therapy intervention was found to be superior to self-help, internet-based therapy.