What is DEPRESSION: A mental health disorder characterized by persistently depressed mood or loss of interest in activities, causing significant impairment in daily life.
Possible causes include a combination of biological, psychological, and social sources of distress. Increasingly, research suggests these factors may cause changes in brain function, including the altered activity of certain neural circuits in the brain.
The persistent feeling of sadness or loss of interest that characterizes major depression can lead to a range of behavioral and physical symptoms. These may include changes in sleep, appetite, energy level, concentration, daily behavior, or self-esteem. Depression can also be associated with thoughts of suicide.
The mainstay of treatment is usually medication, talk therapy, or a combination of the two. Increasingly, research suggests these treatments may normalize brain changes associated with depression.
Depression does not have a single cause. It can be triggered by a life crisis, physical illness, or something else—but it can also occur spontaneously. Scientists believe several factors can contribute to depression:
- Trauma. When people experience trauma at an early age, it can cause long-term changes in how their brains respond to fear and stress. These changes may lead to depression.
- Genetics. Mood disorders, such as depression, tend to run in families.
- Life circumstances. Marital status, relationship changes, financial standing, and where a person lives influence whether a person develops depression.
- Brain changes. Imaging studies have shown that the frontal lobe of the brain becomes less active when a person is depressed. Depression is also associated with changes in how the pituitary gland and hypothalamus respond to hormone stimulation.
- Other medical conditions. People who have a history of sleep disturbances, medical illness, chronic pain, anxiety, and attention-deficit hyperactivity disorder (ADHD) are more likely to develop depression. Some medical syndromes (like hypothyroidism) can mimic depressive disorder. Some medications can also cause symptoms of depression.
- Drug and alcohol misuse. 21% of adults with a substance use disorder also experienced a major depressive episode in 2018. Co-occurring disorders require coordinated treatment for both conditions, as alcohol can worsen depressive symptoms.