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Depression

By

William Coryell

, MD, University of Iowa Carver College of Medicine

Last full review/revision Aug 2021| Content last modified Aug 2021
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Depression is a feeling of sadness and/or a decreased interest or pleasure in activities that becomes a disorder when it is intense enough to interfere with functioning. It may follow a recent loss or other sad event but is out of proportion to that event and lasts beyond an appropriate length of time.

  • Heredity, side effects of drugs, emotionally distressing events, changes in levels of hormones or other substances in the body, and other factors can contribute to depression.

  • Depression can make people sad and sluggish and/or lose all interest and pleasure in activities they used to enjoy.

  • Doctors base the diagnosis on symptoms.

  • Antidepressants, psychotherapy, and sometimes electroconvulsive therapy can help.

People often use the term depression to describe the sad or discouraged mood that results from emotionally distressing events, such as a natural disaster, a serious illness, or death of a loved one. People may also say they feel depressed at certain times, such as during the holidays (holiday blues) or on the anniversary of a loved one's death. However, such feelings do not usually represent a disorder. Usually, these feelings are temporary, lasting days rather than weeks or months, and occur in waves that tend to be tied to thoughts or reminders of the distressing event. Also, these feelings do not substantially interfere with functioning for any length of time.

After anxiety Overview of Anxiety Disorders Anxiety is a feeling of nervousness, worry, or unease that is a normal human experience. It is also present in a wide range of psychiatric disorders, including generalized anxiety disorder,... read more , depression is the most common mental health disorder. About 30% of people who visit a primary care practitioner have symptoms of depression, but fewer than 10% of these people have major depression.

Depression typically develops during a person's mid teens, 20s, or 30s, although depression can begin at almost any age, including during childhood.

An episode of depression, if untreated, typically lasts about 6 months but sometimes lasts for 2 years or more. Episodes tend to recur several times over a lifetime.

Spotlight on Aging: Depression

Depression affects about 1 of every 6 older people. Some older people have had depression earlier in their life. Others develop it for the first time during old age.

Causes of Depression in Older People

Some causes of depression may be more common among older people. For example, older people may be more likely to experience emotionally distressing events that involve a loss, such as the death of a loved one or a loss of familiar surroundings, as when moving away from a familiar neighborhood. Other sources of stress, such as reduced income, a worsening chronic illness, a gradual loss of independence, or social isolation, may also contribute.

Disorders that can lead to depression are common among older people. Such disorders include cancer Symptoms of Cancer At first, cancer, as a tiny mass of cells, causes no symptoms whatsoever (see also Overview of Cancer). As a cancer grows, its physical presence can affect nearby tissues (see also Warning Signs... read more , heart attack Acute Coronary Syndromes (Heart Attack; Myocardial Infarction; Unstable Angina) Acute coronary syndromes result from a sudden blockage in a coronary artery. This blockage causes unstable angina or heart attack (myocardial infarction), depending on the location and amount... read more Acute Coronary Syndromes (Heart Attack; Myocardial Infarction; Unstable Angina) , heart failure Heart Failure (HF) Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more Heart Failure (HF) , thyroid disorders Overview of the Thyroid Gland The thyroid is a small gland, measuring about 2 inches (5 centimeters) across, that lies just under the skin below the Adam’s apple in the neck. The two halves (lobes) of the gland are connected... read more , stroke Ischemic Stroke An ischemic stroke is death of an area of brain tissue (cerebral infarction) resulting from an inadequate supply of blood and oxygen to the brain due to blockage of an artery. Ischemic stroke... read more Ischemic Stroke , dementia Dementia Dementia is a slow, progressive decline in mental function including memory, thinking, judgment, and the ability to learn. Typically, symptoms include memory loss, problems using language and... read more , and Parkinson disease Parkinson Disease (PD) Parkinson disease is a slowly progressive degenerative disorder of specific areas of the brain. It is characterized by tremor when muscles are at rest (resting tremor), increased muscle tone... read more .

Depression Versus Dementia

In older people, depression can cause symptoms that resemble those of dementia: slower thinking, decreased concentration, confusion, and difficulty remembering, rather than the sadness people tend to associate with depression. However, doctors can distinguish depression from dementia because when depression is treated, people with depression regain their mental function. People with dementia do not. Also, people with depression may complain bitterly about their memory loss and rarely forget important current events or personal matters. In contrast, people with dementia often deny memory loss.

Diagnosis of Depression in Older People

Depression is often difficult to diagnose among older people for several reasons:

  • The symptoms may be less noticeable because older people may not work or may have less social interaction.

  • Some people believe that depression is a weakness and are reluctant to tell anyone that they are experiencing sadness or other symptoms.

  • The absence of emotion may be interpreted as indifference rather than depression.

  • Family members and friends may regard a depressed person's symptoms simply as something that is expected as people get older.

  • The symptoms may be attributed to another disorder, such as dementia.

Because depression may be difficult to identify, many doctors routinely ask older people questions about their mood. Family members should be alert for subtle changes in personality, especially lack of enthusiasm and spontaneity, loss of sense of humor, and new forgetfulness.

Treatment of Depression in Older People

Selective serotonin reuptake inhibitors (SSRIs) are the antidepressants used most often for older people who are depressed because SSRIs are less likely to have side effects. Citalopram and escitalopram are particularly useful.

Causes of Depression

The exact cause of depression is unclear, but a number of factors may make depression more likely. Risk factors include

  • A family tendency (heredity)

  • Emotionally distressing events, particularly those involving a loss

  • Female sex, possibly involving changes in hormone levels

  • Certain physical disorders

  • Side effects of certain drugs

Depression does not reflect a weakness of character and may not reflect a personality disorder, childhood trauma, or poor parenting. Social class, race, and culture do not appear to affect the chance that people will experience depression during their lifetime.

Genetic factors contribute to depression in about half the people who have it. For example, depression is more common among first-degree relatives (particularly in an identical twin) of people with depression. Genetic factors can affect the function of substances that help nerve cells communicate (neurotransmitters). Serotonin, dopamine, and norepinephrine are neurotransmitters that may be involved in depression.

Women are more likely than men to experience depression, although the reasons are not entirely clear. Of physical factors, hormones are the ones most involved. Changes in hormone levels can cause mood changes shortly before menstruation (as part of premenstrual syndrome Premenstrual Syndrome (PMS) Premenstrual syndrome (PMS) is a group of physical and psychologic symptoms that start several days before and usually end a few hours after a menstrual period begins. Premenstrual dysphoric... read more ), during pregnancy, and after childbirth. Some women become depressed during pregnancy or during the first 4 weeks after giving birth (called baby blues or, if the depression is more serious, postpartum depression Postpartum Depression Postpartum depression is a feeling of extreme sadness and related psychologic disturbances during the first few weeks or months after delivery. Women who have had depression are more likely... read more ). Abnormal thyroid function, which is fairly common among women, may also be a factor.

Depression may occur with or be caused by a number of physical disorders and factors. Physical disorders may cause depression directly (as when a thyroid disorder Overview of the Thyroid Gland The thyroid is a small gland, measuring about 2 inches (5 centimeters) across, that lies just under the skin below the Adam’s apple in the neck. The two halves (lobes) of the gland are connected... read more affects hormone levels) or indirectly (as when rheumatoid arthritis Rheumatoid Arthritis (RA) Rheumatoid arthritis is an inflammatory arthritis in which joints, usually including those of the hands and feet, are inflamed, resulting in swelling, pain, and often destruction of joints.... read more Rheumatoid Arthritis (RA) causes pain and disability). Often, a physical disorder both directly and indirectly causes depression. For example, AIDS Acquired immunodeficiency syndrome (AIDS) Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and can cause acquired immunodeficiency syndrome (AIDS). HIV is transmitted... read more Acquired immunodeficiency syndrome (AIDS) may cause depression directly if the human immunodeficiency virus (HIV), which causes AIDS, damages the brain. AIDS may cause depression indirectly by having an overall negative effect on the person’s life.

Many people report feeling sadder in late autumn and winter and blame this tendency on the shortening of daylight hours and colder temperatures. However, in some people, such sadness is severe enough to be considered a type of depression (called seasonal affective disorder).

Emotionally distressing events, such as loss of a loved one, can sometimes trigger depression, but usually only in people who are predisposed to depression, such as those who have family members with depression. However, depression may arise or worsen without any apparent or significant life stresses.

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Symptoms of Depression

Symptoms of depression typically develop gradually over days or weeks and can vary greatly. For example, a person who is becoming depressed may appear sluggish and sad or irritable and anxious.

Many people with depression cannot experience emotions—including grief, joy, and pleasure—in a normal way. The world may appear to have become colorless and lifeless. They lose interest or pleasure in activities that they used to enjoy.

Depressed people may be preoccupied with intense feelings of guilt and self-denigration and may not be able to concentrate. They may experience feelings of despair, loneliness, and worthlessness. They are often indecisive and withdrawn, feel helpless and hopeless, and think about death and suicide Suicidal Behavior Suicide is death caused by an intentional act of self-harm that is designed to be lethal. Suicidal behavior includes completed suicide, attempted suicide, and suicidal ideation. Suicide usually... read more .

Most depressed people have difficulty falling asleep and awaken repeatedly, particularly early in the morning. Some people with depression sleep more than usual.

Poor appetite and weight loss may lead to emaciation, and in women, menstrual periods may stop. However, overeating and weight gain are common in people with mild depression.

Some depressed people neglect personal hygiene or even their children, other loved ones, or pets. Some complain of having a physical illness, with various aches and pains.

The term depression is used to describe several related disorders:

  • Major depressive disorder

  • Persistent depressive disorder

  • Premenstrual dysphoric disorder

Major depressive disorder

People with major depressive disorder are depressed most days for at least 2 weeks. They may appear miserable. Their eyes may be full of tears, their brows may be furrowed, and the corners of the mouth may be turned down. They may slump and avoid eye contact. They may hardly move, show little facial expression, and speak in a monotone.

Did You Know...

  • Depression involves more than feeling sad all the time: People may feel worthless and guilty, lose interest in their normal pleasures, have sleep disorders, or lose or gain weight.

Persistent depressive disorder

People with persistent depressive disorder have been depressed for most of the time for 2 years or more.

Symptoms begin gradually, often during adolescence, and may last for years or decades. How many symptoms are present at one time varies, and sometimes symptoms are less severe than those in major depression.

People with this disorder may be gloomy, pessimistic, skeptical, humorless, and incapable of having fun. Some are passive, lack energy, and keep to themselves. Some constantly complain and are quick to criticize others and reproach themselves. They may be preoccupied with inadequacy, failure, and negative events, sometimes to the point of morbid enjoyment of their own failures.

Premenstrual dysphoric disorder

Severe symptoms occur before most menstrual periods and disappear after they end. Symptoms cause substantial distress and/or greatly interfere with functioning. Symptoms are similar to those of premenstrual syndrome Premenstrual Syndrome (PMS) Premenstrual syndrome (PMS) is a group of physical and psychologic symptoms that start several days before and usually end a few hours after a menstrual period begins. Premenstrual dysphoric... read more but are more severe, causing great distress and interfering with functioning at work and social interactions.

Premenstrual dysphoric disorder may first appear any time after girls start to menstruate. It may worsen as women approach menopause but ends after menopause. It occurs in about 2 to 6% of women who are menstruating.

Women with premenstrual dysphoric disorder have mood swings, suddenly becoming sad and tearful. They are irritable and anger easily. They feel very depressed, hopeless, anxious, and on edge. They may feel overwhelmed or out of control. They often put themselves down.

As with other types of depression, women with this disorder may lose interest in their usual activities, have difficulty concentrating, and feel tired and without energy. They may eat too much and crave certain foods. They may sleep too little or too much.

Like many women whose period is about to start, these women may have tender, swollen breasts and/or achy muscles and joints. They may feel bloated and gain weight.

Prolonged grief disorder

Prolonged grief is persistent sadness following the loss of a loved one. It is different from depression in that the sadness relates specifically to the loss rather than the more general feelings of sadness and failure associated with depression.

Prolonged grief is considered present when grief (as shown by persistent longing or yearning and/or preoccupation with the deceased) is long-lasting (at least 12 months), experienced a great deal of the time, and is deeper than what a person's culture considers typical. It also must be accompanied by 3 or more of the following for at least 1 month to a degree that causes distress or disability:

  • Disbelief

  • Intense emotional pain

  • Feeling of identity confusion

  • Avoidance of reminders of the loss

  • Feelings of numbness

  • Intense loneliness

  • Feelings of meaninglessness

  • Difficulty engaging in ongoing life

Specifiers

Doctors use certain terms to describe specific symptoms that can occur in people with depression. These terms include

  • Anxious distress: People feel tense and unusually restless. They have difficulty concentrating because they worry or fear that something awful may happen or that they may lose control of themselves.

  • Melancholic: People no longer take pleasure in any activities they used to enjoy. They appear sluggish, sad, and despondent. They speak little, stop eating, and lose weight. They may feel excessively or inappropriately guilty. They often awake early in the morning and cannot go back to sleep.

  • Atypical: People may temporarily cheer up when something good happens, such as a visit from their children. They have an increased appetite, resulting in weight gain. They may sleep for long periods of time. They are excessively sensitive to perceived criticism or rejection. They may feel weighted down, as if they can hardly move their legs.

  • Psychotic: People have false beliefs (delusions), often of having committed unpardonable sins or crimes, of having incurable or shameful disorders, or of being watched or persecuted. People may have hallucinations, usually of voices accusing them of various misdeeds or condemning them to death.

  • Catatonic: People are very withdrawn. Thinking, speech, and general activity may slow down so much that all voluntary activities stop. Some people mimic others’ speech (echolalia) or movements (echopraxia).

  • Seasonal: Episodes of depression occur every year at a particular time of year, usually starting in the fall or winter and ending in the spring. These episodes are more common in extreme northern and southern latitudes, where the winter season is typically longer and harsher. People are sluggish. They lose interest in and withdraw from their usual activities. They may also sleep too much and overeat.

Suicide

Thoughts of death are among the most serious symptoms of depression. Many depressed people want to die or feel they are so worthless that they should die. As many as 15% of untreated depressed people end their life by suicide Suicidal Behavior Suicide is death caused by an intentional act of self-harm that is designed to be lethal. Suicidal behavior includes completed suicide, attempted suicide, and suicidal ideation. Suicide usually... read more .

A suicide threat is an emergency. When people threaten to kill themselves, a doctor may hospitalize them so that they can be supervised until treatment reduces the risk of suicide. The risk is especially high in the following situations:

Substance use

Other effects of depression

Depression may reduce the immune system's ability to respond to foreign or dangerous invaders, such as microorganisms or cancer cells. As a result, people with depression may be more likely to get infections.

Depression increases the risk of heart and blood vessel disorders (such as heart attacks) and stroke. The reason may be that depression causes certain physical changes that increase this risk. For example, the body produces more of the substances that help blood clot (clotting factors), and the heart is less able to change how fast it beats in response to different situations.

Diagnosis of Depression

  • A doctor's evaluation

  • Tests to identify disorders that can cause depression

A doctor is usually able to diagnose depression based on symptoms. Doctors use specific lists of symptoms (criteria) to diagnose the different types of depressive disorders. To help distinguish depression from ordinary changes in mood, doctors determine whether the symptoms are causing significant distress or are impairing the person's ability to function. A previous history of depression or a family history of depression helps support the diagnosis.

In older people, depression may be difficult to notice, especially if they do not work or have little social interaction. Also, depression may be mistaken for dementia Dementia Dementia is a slow, progressive decline in mental function including memory, thinking, judgment, and the ability to learn. Typically, symptoms include memory loss, problems using language and... read more because it can cause similar symptoms, such as confusion and difficulty concentrating and thinking clearly. However, when such symptoms are caused by depression, they resolve when depression is treated. When dementia is the cause, they do not resolve.

Standardized questionnaires are used to help identify depression and determine how severe it is, but they cannot be used alone to diagnose depression. Two such questionnaires are the Hamilton Depression Rating Scale, conducted verbally by an interviewer, and the Beck Depression Inventory, a self-administered questionnaire. For older people, there is a Geriatric Depression Scale questionnaire. Doctors also ask people whether they have any thoughts or plans to harm themselves. Such thoughts indicate that depression is severe.

Testing

Treatment of Depression

Most people with depression do not require hospitalization. However, some people should be hospitalized, especially if they are contemplating suicide or have attempted it, are frail because of weight loss, or are at risk of heart problems because of severe agitation.

Treatment depends on the severity and type of depression:

  • Mild depression: Support (including frequent doctor visits and education) and psychotherapy

  • Moderate to severe depression: Drugs, psychotherapy, or both and sometimes electroconvulsive therapy

  • Seasonal depression: Phototherapy

  • Prolonged grief disorder: Psychotherapy tailored to this disorder

Depression can usually be treated successfully. If a cause (such as a drug or another disorder) can be identified, it is corrected first, but drugs to treat depression may also be needed.

Support

Doctors may schedule visits or telephone calls every week or every other week for people with depression. Doctors explain to them and their family members that depression has physical causes and requires specific treatment, which is usually effective. Doctors reassure them that depression does not reflect a character flaw, such as weakness. It is important for family members to understand the disorder, be involved in treatment, and provide support.

Learning about depression can help people understand and deal with the disorder. For example, people learn that the path to recovery is often bumpy and that episodes of sadness and dark thoughts may recur but they will stop. Thus, people can put any setbacks in perspective and are more likely to continue their treatment and not give up.

Becoming more active—taking walks and exercising regularly—can help, as can interacting more with others.

Support groups (such as the Depression and Bipolar Support Alliance—DBSA) can help by providing a forum to share common experiences and feelings.

Psychotherapy

Psychotherapy alone may be just as effective as drug therapy for mild depression. When used with drugs, it can be useful for severe depression.

Individual or group psychotherapy can help people with depression gradually resume former responsibilities and adapt to the normal pressures of life. Interpersonal therapy focuses on the person's past and present social roles, identifies problems with how the person interacts with other people, and provides guidance as the person adjusts to changes in life roles. Cognitive-behavioral therapy can help change hopelessness and negative thinking.

Drug therapy for depression

Psychostimulants Drug therapy Attention-deficit/hyperactivity disorder (ADHD) is poor or short attention span and/or excessive activity and impulsiveness inappropriate for the child’s age that interferes with functioning... read more , such as dextroamphetamine and methylphenidate, as well as other drugs, are sometimes used, often with antidepressants. Psychostimulants are used to increase mental alertness and awareness.

St. John’s wort St. John’s Wort The reddish substance in the plant’s flowers contains numerous biologically active compounds, including hypericin and hyperforin. (See also Overview of Dietary Supplements.) People take St.... read more , an herbal dietary supplement, is sometimes used to relieve mild depression, although its effectiveness is not proven. Due to potentially harmful interactions between St. John’s wort and many prescription drugs, people interested in taking this herbal supplement need to discuss possible drug interactions with their doctor.

Electroconvulsive therapy

Electroconvulsive therapy (in the past sometimes called shock therapy) is sometimes used to treat people with severe depression, including people who are psychotic, threatening suicide, or refusing to eat. It is also used to treat depression during pregnancy when drugs are ineffective.

This type of therapy is usually very effective and can relieve depression quickly, unlike most antidepressants, which can take up to several weeks. The speed with which it takes effect can save lives. After electroconvulsive therapy is stopped, episodes of depression can recur. To help prevent them, doctors often prescribe antidepressants.

For electroconvulsive therapy, electrodes are placed on the head, and an electrical current is applied to induce a seizure in the brain. For reasons that are not understood, the seizures relieve depression. Usually, at least five to seven treatments (one treatment every other day) are given.

Because the electrical current can cause muscle contractions and pain, general anesthesia is required during treatments. Electroconvulsive therapy may cause some temporary memory loss and, rarely, permanent memory loss.

Phototherapy

Phototherapy using a light therapy box is the most effective treatment for seasonal depression but may be helpful for other types of depressive disorders.

Phototherapy involves sitting a specific distance from a light box that provides light with the necessary intensity. People are instructed not to look directly at the light and to remain in front of the light for 30 to 60 minutes a day. Phototherapy can be done at home.

If people go to sleep and get up late, phototherapy is most effective in the morning. If people go to sleep and get up early, phototherapy is most effective between the late afternoon and early evening.

Other therapies

Other therapies that stimulate the brain may be tried when other treatments are ineffective. They include

  • Repetitive transcranial magnetic stimulation

  • Stimulation of the vagus nerve

The stimulated cells are thought to release chemical messengers (neurotransmitters), which help regulate mood and may thus relieve symptoms of depression. These therapies may help people with severe depression that does not respond to drugs or psychotherapy.

For repetitive transcranial magnetic stimulation, an electromagnetic coil is placed against the forehead near an area of the brain thought to be involved in regulating mood. The electromagnet produces painless magnetic pulses that doctors think stimulate nerve cells in the targeted area of the brain. The most common side effects are headaches and discomfort near where the coil was placed.

For vagus nerve stimulation, a device that looks like a heart pacemaker (vagus nerve stimulator) is implanted under the left collarbone and is connected to the vagus nerve in the neck with a wire that runs under the skin. (The pair of vagus nerves run from the brain stem, located near the base of the skull, through the neck and down each side of the chest and abdomen to organs, such as the heart and lungs.) The device is programmed to periodically stimulate the vagus nerve with a painless electrical signal. It may be useful for depression when other treatments are ineffective, but it usually takes 3 to 6 months to take effect. Side effects of vagus nerve stimulation include hoarseness, cough, and deepening of the voice when the nerve is stimulated.

More Information

The following are some English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

Drugs Mentioned In This Article

Generic Name Select Brand Names
DEXEDRINE
CONCERTA, RITALIN
REGLAN
CRINONE
LEXAPRO
SEROMYCIN
MARQIBO KIT
No US brand name
No brand name
TAGAMET
CELEXA
KETALAR
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