Major depression is a common medical condition characterized by many different physical and psychological symptoms, including profound sadness, loss of interest or pleasure in activities normally enjoyed and other symptoms that impair a person’s ability to function.

Major depression is a type of mood disorder. Depression in all its forms is not “the blues” or occasional sadness or grief, which is a normal response to loss. Major depression is a persistent condition that interferes with a person’s lifestyle, activities and relationships.

Episodes of major depression may occur suddenly or gradually and usually last several months. It is common for episodes to recur and suicide is a major risk.

The cause of depression is not known, but a number of advances have been made in identifying potential factors. Most likely, it is a combination of genetic and environmental factors that are involved in the development of the disorder. Major depression tends to run in families, and it may be triggered by severe stress (e.g., abuse, death of a loved one). Depression is more common in women and people with chronic medical conditions.

Many people with symptoms of depression first visit their primary care physician for help. The physician may perform a physical examination to rule out possible physical causes of the symptoms. Afterward, a mental health evaluation may be performed by either a physician or a mental health professional.

To be diagnosed with major depression, a patient must show at least five of the nine primary symptoms including altered mood or loss of interest or pleasure in activities. These symptoms must occur most of the day, nearly every day, for at least two weeks and must be severe enough to cause distress or impair function.

Certain conditions or situations may affect whether depression is diagnosed. These include some instances of alcohol or substance abuse or cases where a person recently experienced the death of a loved one. Some symptoms of depression are a normal part of grief, especially in the first few months. However, if the symptoms continue, a grieving person may be diagnosed with depression. The presence of many other mental disorders (e.g., schizophrenia, delusional disorder, bipolar disorder) will also exclude the diagnosis of major depression.

People with mild major depression may respond well with psychotherapy alone, whereas those with moderate to severe depression may require medication treatment (e.g., antidepressants). The outcome of treatment is generally best with a combination of psychotherapy and medication. When major depression is life threatening or severe in patients who cannot take medications, or medications do not provide sufficient relief, electroconvulsive therapy may be recommended.