If your parent lives with depression, does this mean you’ll inherit it? Genes may impact mental conditions, but heredity isn’t the only factor.
Depression is one of the most common mental health conditions around the globe, affecting
Researchers know that depression runs in families, but there are still questions about how much of your risk is affected by genes alone.
Can certain situations or behaviors — like living in an under-resourced community or using substances — trigger hereditary depression?
There may be protective factors that people with a higher genetic risk can take, such as cultivating the right home environment, getting enough sleep, and eating nutritious foods.
Depression can run in families. But having a parent or a sibling with depression doesn’t necessarily mean you’ll have it, too.
If depression runs in your family, you have about a 30% chance of developing it, compared to the typical 10% chance in the general population.
However, recurrent depression may carry a higher genetic risk.
For example, if your parent or sibling has experienced a depressive episode more than once, especially starting earlier in life (anytime from their childhood to their 20s), your risk may be 4 or 5 times greater than the average person’s.
Many people experience more than one depressive episode. Nearly 3 in 4 people with depression will experience a relapse at some point in their lives.
Some disorders, such as cystic fibrosis and sickle cell anemia, are caused by a single gene. But similar to other common genetic conditions like diabetes, depression is not caused by one gene.
Instead, depression is influenced by a complex interplay of genes, biological factors, and environmental causes.
So while depression does run in families, you don’t simply “inherit” this mental health condition from your mom or dad. Your parents contribute certain combinations of genes that can make you more likely to develop the illness.
Other factors such as trauma, substance use, and family environment can also affect your odds.
Twin and family studies suggest a genetic link to depression
Thanks to family and twin studies, researchers know that genes play a significant role in developing depression.
In these studies, researchers compare identical twins (who share 100% of their gene profile) to help shed light on how much of the risk is genetic.
Therefore, if genes are part of the cause, the researchers would expect an identical twin to have a much higher risk of depression than a non-identical twin (who shares only 50% of their genes).
Through studies like these, researchers have determined that heritability is probably around 40% to 50%, and may be even higher for severe depression.
Genome studies on family history of depression
Recent advancements in science and technology have allowed researchers to conduct large-scale genome studies to explore how our genes are related to depression.
A genome-wide association study (GWAS) is a type of study that involves scanning complete sets of DNA, or genomes, of large numbers of people in order to detect any genetic patterns linked to a particular disease.
Once these genetic links are found, scientists use the data to develop better ways to detect, prevent, and treat disease.
Until recently, gene studies on depression have focused primarily on “candidate genes,” or genes believed to be involved in the development of depression.
Some of the most commonly studied candidate genes have included those regulating serotonin or dopamine, since these neurotransmitters are believed to play a role in depression and are the targets of antidepressant drugs.
However, it’s been hard to repeat these findings. The newer GWAS takes a completely different approach. Rather than looking at specific candidate genes, the GWAS method allows researchers to analyze a million or more variants across the entire genome.
In a major GWAS of 1.2 million people from four separate data banks, researchers identified 178 gene variants linked to major depression. The researchers think they may just be scratching the surface, as there may be hundreds — or even thousands — of these gene variants to discover.
These types of large-scale findings allow clinicians to develop
The genome-wide approach can also help researchers develop new medications. For instance, several gene variants linked to depression have been shown to affect the glutamate system, which is currently being studied for depression treatments.
While many things can factor into the risk of developing depression, researchers found that family environment may play a key role.
According to a Swedish adoption study, family environment could be a “protective” factor for people who have high-risk genes for major depression.
The study defines a “high-quality family environment” as one not affected by divorce or parental death before the child turned 15 years old.
Low levels of psychiatric drug or substance use, high educational status, and economic security in the adoptive parents were also considered positive for providing a stable home environment, according to researchers.
Families can come in many different types. A healthy, high-quality family environment can be whatever home environment or family structure that feels most comfortable and right for you and your loved ones.
Researchers looked at a sample of 2,596 half-sibling pairs who had at least one biological parent with major depression, putting them at high risk for major depression. They also looked at more than 660 high-risk full-sibling pairs.
Each sibling pair involved at least one adopted-away sibling and one home-reared sibling.
After controlling for important factors, the researchers found that high-risk half-siblings who’d been adopted into healthy family environments were 19% less likely to develop major depression, compared to the home-reared sibling.
Adopted-away high-risk full siblings were 23% less likely to develop depression than their home-reared siblings.
Importantly, in both half- and full-sibling pairs, the protective effects of adoption disappeared when a step-sibling or an adoptive parent had major depression or if the adoptive home had been affected by divorce or parental death.
Like many psychiatric disorders, depression is complex and can be “triggered” or made worse by other factors, such as stress, nutrition, and other medical conditions.
There is often more than one factor involved in the onset of depression. Besides genes, depression has been linked to the following:
Physiological factors
- neurotransmitter abnormalities
- chemical mood regulations in the brain
- medication
- other medical conditions
- older age
- sleep disruptions
Situational factors
- nutrition
- living in an under-resourced community
- substance use
- severe life stress
- childhood trauma
- childhood emotional and physical neglect
- losing a parent in early life
If you’re currently living with depression, you’re not alone. Depression is one of the most commonly occurring mental health conditions for millions of people across the globe.
There are many resources you can take advantage of to feel better, no matter where you are on your mental wellness journey.
You may have to try many different approaches until you find what works for you, but it is possible to feel better when living with depression.
Strategies for managing depression don’t have to be complicated, either. If you think you may be experiencing depression, here are some things you can do to feel better right away.
Trying things like eating nutritious foods, getting enough sleep, spending time outdoors, and exercising lightly could help alleviate depression symptoms.
People with depression may also benefit from building a support network of friends and family who they feel comfortable reaching out to when experiencing low moods.
Getting support from a professional from the comfort of your home can be easy with therapy apps.
- Youper. This self-guided therapy app was created by doctors and therapists using artificial intelligence to generate daily therapeutic exercise recommendations.
- SuperBetter. This game app teaches users skills to overcome difficult life situations and alleviate depression symptoms, created by a game designer living with depression.
- Dailyo. Track your emotions with this digital bullet-journaling app. Set goals with customized colors, themes, and emojis, and chart the statistics of your moods over time monthly or annually.
For more information on seeking help for depression, visit the National Alliance on Mental Health.