Depression is a mood disorder characterized by a persistent sad or empty feeling, irritability, and a loss of interest in everyday activities. The condition is twice as common in women as in men and is usually episodic. But unlike normal sadness or grieving, most bouts of depression last for weeks, months, or even years.

Some people with depression have a chronic, low-grade form of the condition called dysthymia. A smaller number suffer from bipolar disorder—bouts of depression interspersed with periods of elevated (manic) mood.

Although depression is usually not considered life-threatening, it can lead to thoughts of and attempts at suicide. As many as 70 percent of suicides in the United States are related to depression, and up to 15 percent of severely depressed people commit suicide.

Fortunately, the overwhelming majority of people with depression can be helped by counseling (psychotherapy), antidepressant drugs, or other therapies, thus lowering the suicide risk.

Symptoms of Depression

• Persistent feelings of sadness, apathy, or hopelessness lasting more than two weeks.

   

• Diminished interest in most daily activities, particularly pleasurable ones.

   

• Decreased appetite and subsequent weight loss; increased appetite and weight gain.

   

• Lack of sleep (insomnia), frequent awakening throughout the night, or conversely, an increased need for sleep.

   

• Anxiety; diminished ability to think or concentrate.

   

• Older people may initially focus on physical or cognitive complaints brought on by their depression. Insomnia and agitation are also more common in older patients.

What Causes Depression?

• Although the cause of most cases of depression is unknown, it is thought to be associated with a combination of medical, genetic, and environmental factors.

   

• Imbalances of chemicals that transmit nerve signals (neurotransmitters) in the brain may play a role.

   

• The condition appears to run in families, although no specific genes have been identified.

   

• Episodes may be connected to major life events, such as the death of a loved one or loss of a job.

   

• In about 15 percent of cases, depression develops in response to a medical illness (especially heart disease, cancer, or a neurologic disorder such as Parkinson’s disease or stroke) or from long-term use of some medications, including beta-blockers for high blood pressure and corticosteroids for arthritis. Other causes of this “secondary depression” include alcoholism, an underactive thyroid gland, vitamin deficiencies, and schizophrenia.

Prevention of Depression

• Although the initial onset of depression cannot be prevented, recurrent episodes may be controlled or avoided altogether with ongoing psychotherapy and/or drug therapy. The longer a person stays in treatment, the less likely a relapse will occur.

Diagnosis of Depression

• Because there are no reliable laboratory tests to diagnose depression, physical examination and psychological evaluation are essential.

   

• Expression of either of the first two symptoms of depression, in conjunction with other symptoms, for a period of two or more consecutive weeks.

   

• A positive family history of depression or a prior depressive episode helps establish the diagnosis.

How To Treat Depression

• Psychotherapy is as effective as drug treatment in mild cases. Psychotherapy may also be used in conjunction with drug therapy.

   

• Antidepressant medications, such as selective serotonin reuptake inhibitors (SSRIs), tricyclics, and monoamine oxidase (MAO) inhibitors, are mainstays of treatment.

   

• Electroconvulsive therapy (using an electric current to cause a brief convulsion) is sometimes used in severe cases.

   

• Exposure to bright light, known as light therapy, may be effective, particularly when depression is related to seasonal changes (seasonal affective disorder).

   

• In secondary depression, the underlying cause is addressed, although antidepressant therapy may also be prescribed.

When To Call A Doctor

• Anyone with symptoms of depression should see a doctor for an evaluation and possible referral to a mental health professional.

   

• Emergency: Anyone who has persistent thoughts of suicide should get immediate psychological or medical treatment.

For more information on depression and related mood disorders, click on this link -- Johns Hopkins Health Alerts: Depression and Anxiety