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(Major Depressive Affective Disorder; Unipolar Disorder; Unipolar Mood Disorder)

En Español (Spanish Version)More InDepth Information on This Condition


Depression is a mental illness marked by feelings of profound sadness and lack of interest in activities. Depression is not the same as a blue mood. It is a persistent low mood that interferes with the ability to function and appreciate things in life. It may cause a wide range of symptoms, both physical and emotional. It can last for weeks, months, or years. People with depression rarely recover without treatment.


The precise cause is not known. It can be difficult to determine if an illness causes depression or depression caused the illness. Possible causes may be mental, physical, or environmental and include:

  • Stressful life events (usually in combination with one or more of the following causes)
  • Chronic stress
  • Low self-esteem
  • Imbalances in brain chemicals and hormones
  • Lack of control over circumstances (helplessness and hopelessness)
  • Negative thought patterns and beliefs
  • Chronic pain
  • Heart disease and heart surgery
  • Genetic predisposition
  • Altered brain structure and function, including after a stroke
  • Parkinson’s disease
  • Postpartum depression occurs after childbirth
  • Seasonal affective disorder is a type of depression or a worsening of symptoms thought to be due to the decreased exposure to sunlight that occurs during winter months
  • Hypothyroidism
  • Anemia
  • Cancer
  • Substance abuse


Brain Man Face

Chemical, hormonal, and physical changes in the brain may cause depression.

© 2008 Nucleus Medical Art, Inc.

Risk Factors

Risk factors include:

  • Sex: female
  • Age: elderly
  • Chronic physical or mental illness, including thyroid disease, headaches, chronic pain, and stroke
  • Previous episode of depression
  • Major life changes or stressful life events (eg, bereavement, trauma)
  • Postpartum depression
  • Winter season for seasonal affective disorder
  • Little or no social support
  • Low self-esteem
  • Lack of personal control over circumstances
  • Family history of depression (parent or sibling)
  • Feelings of helplessness
  • Certain medications, including medications used to treat asthma , high blood pressure , arthritis, high cholesterol , and heart problems
  • Smoking
  • Anxiety
  • Insomnia
  • Personality disorders
  • Hypothyroidism


Depression can differ from person to person. Some people have only a few symptoms, while others have many.

Symptoms can change over time and may include:

  • Persistent feelings of sadness, anxiety, or emptiness
  • Hopelessness
  • Feeling guilty, worthless, or helpless
  • Loss of interest in hobbies and activities
  • Loss of interest in sex
  • Feeling tired
  • Trouble concentrating, remembering, or making decisions
  • Trouble sleeping, waking up too early, or oversleeping
  • Eating more or less than usual
  • Weight gain or weight loss
  • Thoughts of death or suicide with or without suicide attempts
  • Restlessness or irritability
  • Physical symptoms that defy standard diagnosis and do not respond well to medical treatments


There is no blood test or diagnostic test for depression. The doctor will ask about your symptoms and medical history, giving special attention to:

  • Alcohol and drug use
  • Thoughts of death or suicide
  • Family members who have or have had depression
  • Sleep patterns
  • Previous episodes of depression

The doctor may also perform specific mental health exams. This will help get detailed information about your speech, thoughts, memory, and mood. A physical exam and other tests can help rule out other causes.


Treatment may involve the use of medicine, psychotherapy, or the use of both.

Severe depression usually requires hospital care and the use of drugs, such as olanzapine .

Antidepressant Medications

Up to 70% of depressed patients find relief from their symptoms with medicine. They can take 2 to 6 weeks to reach their maximum effectiveness. The medications include:

Selective Serotonin Reuptake Inhibitors (SSRIs)

  • Fluoxetine (eg, Prozac)
  • Sertraline (eg, Zoloft)
  • Paroxetine (eg, Paxil)
  • Citalopram (eg, Celexa)
  • Fluvoxamine (eg, Luvox)
  • Escitalopram (eg, Lexapro)

***Please note: In March, 2004, the Food and Drug Administration (FDA) issued a Public Health Advisory that cautions physicians, patients, families, and caregivers of patients with depression to closely monitor both adults and children receiving certain antidepressant medications. The FDA is concerned about the possibility of worsening depression and/or the emergence of suicidal thoughts, especially among children and adolescents at the beginning of treatment, or when there’s an increase or decrease in the dose. The medications of concern—mostly SSRIs (Selective Serotonin Re-uptake Inhibitors)—are: Prozac (fluoxetine), Zoloft (sertraline), Paxil (paroxetine), Luvox (fluvoxamine), Celexa (citalopram), Lexapro (escitalopram), Wellbutrin (bupropion), Effexor (venlafaxine), Serzone (nefazodone), and Remeron (mirtazapine). Of these, only Prozac (fluoxetine) is approved for use in children and adolescents for the treatment of major depressive disorder. Prozac (fluoxetine), Zoloft (sertraline), and Luvox (fluvoxamine) are approved for use in children and adolescents for the treatment of obsessive compulsive disorder. For more information, please visit .

Tricyclic Antidepressants

  • Imipramine (eg, Tofranil)
  • Doxepin (eg, Adapin, Sinequan)
  • Clomipramine (eg, Anafranil)
  • Nortriptyline (eg, Pamelor)
  • Amitriptyline (eg, Elavil)

Monoamine Oxidase Inhibitors (MAOIs)

  • Phenelzine (eg, Nardil)
  • Tranylcypromine (eg, Parnate)

Other Antidepressants

  • Venlafaxine (eg, Effexor)
  • Nefazodone (eg, Serzone)
  • Mirtazapine (eg, Remeron)
  • Bupropion (eg, Wellbutrin)
  • Duloxetine (eg, Cymbalta)


Short-term (10 to 20 weeks) therapy can help some people. Psychotherapy is designed to help you:

  • Cope with difficulties in relationships
  • Change negative thinking and behavior patterns
  • Resolve difficult feelings

Electroconvulsive Therapy (ECT)

ECT is the use of an electric stimulus to produce a generalized seizure. It may be used in people with severe or life-threatening depression. ECT is also used for people who cannot take or do not respond to medicine. It is considered a safe and effective procedure.


Regular exercise has been shown to relieve some of the symptoms. It should play a large role in the overall management of depression.


This therapy is done by sitting under special lights. It usually lasts about 30 minutes every morning.

Dietary Supplement and Herbal Therapy

St. John's wort is an herb that is available without prescription. It is widely used in Europe for the treatment of mild to moderate depression. However, there is conflicting evidence as to its whether or not the herb is effective.

There is also recent evidence that DHEA, a dietary supplement, may help some people. DHEA is an ingredient in fish oil . Some experts disagree with these findings. Always discuss the use of dietary and herbal supplements with your doctor.

Dietary Manipulations

Research suggests that diets high in tryptophan, certain B vitamins , and fish oil may be helpful. They have shown promise in both relieving and preventing depression. Always discuss the use of such supplements with your doctor.

Vagal Nerve Stimulation (VNS)

VNS is used as therapy for depression when multiple trials of medicine do not work. A pacemaker-like device stimulates the vagus nerve, in the neck.

Vagus Nerve

Vagus Nerve

Stimulation of the vagus nerve (yellow) at the neck is a depression therapy option.

© 2008 Nucleus Medical Art, Inc.


Strategies to reduce your chance of becoming depressed include:

  • Being aware of your personal risk
  • Having a psychiatric evaluation and psychotherapy if needed
  • Developing social supports
  • Learning stress management techniques
  • Exercising regularly
  • Do not abuse or overuse alcohol or drugs
  • Getting adequate sleep, rest, and recreation


Depression and Bipolar Support Alliance

International Foundation for Research and Education on Depression

The National Mental Health Association


Canadian Mental Health Association

Canadian Psychiatric Association


Depression. National Institute of Mental Health website. Available at: . Accessed July 21, 2008.

Factsheet: depression. The National Mental Health Association website. Available at: . Accessed July 21, 2008.

Groves DA, Brown VJ. Vagal nerve stimulation: a review of its applications and potential mechanisms that mediate its clinical effects. Neurosci Biobehav Rev . 2005;29:493-500.

Medical Letter, Inc. Treatment Guidelines from the Medical Letter. Medical Letter . 2003;1:11.

Last reviewed February 2008 by Rosalyn Carson-DeWitt, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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