What Causes Depression and How Common Is It?

Major depression is a common psychiatric disorder, but it’s more common in adolescent and adult women than in adolescent and adult men.

Between 15 to 20 out of every 100 people (15-20%) experience an episode of major depression during their lifetime. Its prevalence has not been found to be related to ethnicity, income, education, or marital status.

Causes of Depression

There is no simple answer to what causes depression. Research shows that the risk for depression is a result of how our genes interact with our environment. This is called the stress-vulnerability model. Several factors play a part in the onset of the disorder, including:

• Genetic or family history of depression
• Environmental stressors
• Life events
• Biological factors
• Psychological vulnerability to depression

Genetic Factors

A family history of depression does not necessarily mean children or other relatives will develop major depression. However, those with a family history of depression have a slightly higher chance of becoming depressed at some stage in their lives. Although genetic research suggests that depression can run in families, genetics alone are unlikely to cause depression.

Environmental Stressors and Life Events

Environmental factors, such as a traumatic childhood or adult life events, may act as triggers for depression. Studies show that early childhood trauma and losses, such as the death or separation of parents, or adult life events, such as the death of a loved one, divorce, the loss of a job, retirement, serious financial problems, and family conflict, can lead to the onset of depression. Subsequent episodes are usually caused by more mild stressors or even none at all.

Biological Factors

Many scientists believe the cause is biological, such as an imbalance in brain chemicals, specifically serotonin and norepinephrine. There are also theories that physical changes to the body may play a role in depression, such as viral and other infections, heart attack, cancer, or hormonal disorders.

Personality Style

Personality style may also contribute to the onset of depression. People are at a greater risk of becoming depressed if they have low self-esteem, tend to worry a lot, are overly dependent on others, are perfectionists, or expect too much from themselves and others.

Want to Learn More?

Here are some other articles you might find helpful:

• Major Depression: The Symptoms