Written by Stephanie Faris | Published on August 12, 2014
Medically Reviewed by George Krucik, MD on August 12, 2014
Part 1 of 5: Overview
Is Depression Genetic?
Maybe your mother had it. Or your uncle or your sister. Watching a family member suffer from depression can be difficult. But does that mean you also will suffer from the condition?
Clinical depression, also known as major depressive disorder, is the most common form of depression. The Stanford School of Medicine (SSM) estimates that 10 percent of Americans will experience this type of depression at some point in their lives. This type is also more likely to be shared by siblings and children. A person with a relative who suffers from depression is almost five times more likely to develop depression as well.
Still, research has explored the possibility of a connection between genes and depression. Is depression hereditary, or are other factors involved?
Part 2 of 5: Genetics
The Depression Gene
A British research team recently isolated a gene that appears to be prevalent in multiple family members with depression. The chromosome 3p25-26 was found in more than 800 families with recurrent depression. Scientists believe as much as 40 percent of those with depression can trace it to a genetic link. Environmental and other factors make up the other 60 percent.
Research has also shown that people with parents or siblings who have depression are up to three times more likely to have the condition. This can be due to heredity or environmental factors that have a strong influence.
Part 3 of 5: Other Factors
A person who grows up with someone with depression may be more susceptible to the disease. A child who watches a depressed parent or sibling may learn to mimic that person’s behavior under certain conditions. A child who sees a parent spend days in bed may not think it unusual. Gender also may be a factor. One study found that women had a 42 percent chance of hereditary depression, while men had only a 29 percent chance.
Part 4 of 5: Serotonin
The Serotonin Link
Researchers have also linked serotonin to depression. Serotonin is the “feel-good” chemical that allows communication between brain neurons. It is possible that an imbalance in serotonin can lead to mood disorders and other issues such as obsessive-compulsive disorder and panic attacks.
There are many theories about the serotonin-depression link. Researchers continue to study serotonin as the key to the genetic link. Problems with the serotonin transporter gene have also been considered as a source for depression. Research has traced the presence of long and short transporter genes to a possible genetic connection.
Part 5 of 5: Outlook
Many researchers believe it is not a singular gene that puts someone at risk for mental illness. It is more likely a combination of genes that lead to the disorder. The causes of bipolar disorder and anxiety disorders may also be traced to a combination of genetic factors.
The question remains: should someone whose parent or sibling suffers from depression be worried? The answer: not necessarily. Situational depression is often only temporary. It is brought on by major life events, and treatment is available. It is certainly something to watch out for, but not something to worry about.