I always thought my depression might be inherited because both my parents have experienced it. But we all shared the same house, town, financial situation, and social network when I was growing up, so I wondered if it was more a product of our environment than our genes. As it turns out, both are correct. Experts think depression is about 50 percent inherited and 50 percent other factors.
This balance between genetics and environment makes depression complex. It's not a condition that can be explained by one single cause. Instead, it arises from multiple contributing influences that vary from person to person.
How Depression Is Inherited
Unlike some diseases, depression isn't caused by a single defective gene. A recent study identified 178 gene variants linked to major depressive disorder.
These 178 genes play a wide variety of roles in the brain. Some are involved in the growth and maintenance of nerve cells; others produce chemicals called neurotransmitters, which help nerve cells communicate with each other. Some control synaptic plasticity, or the ability of synapses (connections between nerve cells) to adapt to stimuli. All of these contribute to the overall biochemical balance in the brain, which helps shape a person's mental health.
The Odds of Inheriting Depression
Does this mean that if you have a family member living with depression, you're destined to experience it too? Because the genetics of depression are so complicated, the answer is: not necessarily. Scientists estimate that having a parent or sibling with major depressive disorder doubles or triples your risk of developing depression, but there are many non-genetic risk factors as well.
Traumatic or stressful life events like violence, abuse, or the loss of a loved one can increase your risk of depression. Substance abuse and other mental illnesses can also play a role. Environmental factors like social relationships and financial circumstances can shape depression, and other mental health conditions, in complex ways.
The Complexity of Risk
As a result, there's no way to determine if you will experience depression, when it will happen, or whether it will recur. This uncertainty can add to the burden of coping with depression, because you may never fully understand where it came from.
Even if you inherit depression from your parents, your symptoms may be very different from theirs—and treatments that helped them may not work for you. Depression manifests in highly individual ways, shaped by both biology and personal experiences.
Understanding What Inheritance Means
On the other hand, looking at depression this way can offer some comfort—because it's not your fault. When experiencing depression and other mental illnesses, it's easy to wonder if there's something wrong with you or if you somehow caused your disease. But, as with physical illnesses, depression is the result of a complex combination of factors, both inherited and otherwise.
Recognizing the balance between genetics and environment can help reduce stigma and self-blame. Understanding that depression is influenced by biology, circumstances, and personal history is an important step toward seeking the right treatment and support.