Genetics
Genetic factors are thought to have a role in the development of depression. Studies have shown that people who have a family history of depression are more likely to experience depression themselves. Additionally, certain genetic variations, such as those associated with the serotonin transporter gene, have been linked to an increased risk of developing depression.
Brain Chemistry
Depression is thought to be associated with an imbalance of certain chemicals in the brain, such as serotonin and norepinephrine. These chemicals are involved in regulating mood, and an imbalance can lead to feelings of sadness, anxiety, and hopelessness.
Hormones
Hormonal imbalances can also play a role in the development of depression. Low levels of certain hormones, such as thyroid hormones, have been linked to a higher risk of depression. Additionally, changes in hormone levels associated with menstruation, pregnancy, and menopause can also increase the risk of depression.
Stress
Stressful life events, such as the death of a loved one, a divorce, or a job loss, can trigger depression in some people. Chronic stress can also lead to depression, as can a history of traumatic or abusive experiences.