Major Depression – Causes, Signs and symptoms

Major Depression

Also called: Major Depressive Episode, Depressive Disorder, Major Depressive Disorder, Clinical Depression, Depressive Episode, Depression, Unipolar Depression


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.

About major depression

Major depression is a disorder characterized by an altered, usually profoundly sad mood and a loss of interest or pleasure in activities that were once enjoyable (anhedonia). This disorder also impairs the patient’s ability to function (e.g., in school, at work).

Depression may be classified as mild, moderate or severe in intensity. Episodes of major depression may occur suddenly or gradually over time. Patients may experience a single episode or recurrent episodes. An episode may last from a few weeks to many years, but most last between six and nine months.

In most cases, symptoms of major depression disappear completely or almost completely at the end of an episode. However, sometimes only some of the symptoms disappear or the episode does not seem to end at all. Depression that lasts for at least two years is known as chronic depression or is sometimes referred to as dysthymia.

Although major depression varies widely between patients, the symptoms in a given patient usually remain consistent from one episode to the next. Multiple episodes tend to increase the degree of impairment. Further, the risk of future episodes increases with each additional episode. According to the American Psychiatric Association (APA):

  • Patients who experience one episode of major depression have a 60 percent risk of experiencing a second episode

  • Patients who experience two episodes have a 70 percent risk of experiencing a third episode

  • Patients who experience three episodes have a 90 percent risk of experiencing a fourth episode

Although depression can affect individuals of all ages, it tends to begin during the mid-20s or early-30s. Major depression also does occur in children and adolescents.

According to the National Institute of Mental Health (NIMH), major depression affects approximately 14.8 million American adults each year. Following puberty, it affects women nearly twice as often as men, with women aged 18 or older accounting for the majority of cases.

In addition, about 2 percent of children between the ages of 6 and 12 years suffer from major depression at any given time. This rate increases to 4 percent at puberty. In all, around 20 percent of all individuals will have at least one episode of major depression before they reach adulthood.

Major depression often follows severe mental stress (e.g., death of a loved one, divorce). It may also affect women after childbirth (postpartum depression). Other episodes of depression occur during the winter and symptoms go away during the summer (seasonal affective disorder).

Suicide is a major risk with major depression. According to the APA, as many as 15 percent of patients with major depression die by suicide, and this number is even greater among elderly people. Multiple episodes of depression greatly increase the risk of suicidal thoughts and attempts.

The suicide risk is also of particular concern with children and adolescents suffering from major depression. Suicide rates among young people have nearly tripled since 1960. According to the National Mental Health Association (NMHA), almost 5,000 individuals between the ages of 15 and 24 years kill themselves each year. This makes suicide the third leading cause of death in adolescents and the second leading cause of death among college-age youth. It is believed that most of these suicide victims suffered from untreated depression.

Dysthymia is a chronic but less severe form of depression in which depression symptoms last at least two years. Patients who suffer from dysthymia are usually able to function adequately. There is a close relationship between major depression and dysthymia. For instance, many patients with dysthymia will eventually develop major depression, and patients with major depression may eventually develop dysthymia. Patients with dysthymia may develop a major depressive episode that is referred to as double depression.

In addition, about 5 to 10 percent of patients who have had a major depressive episode will eventually have a manic episode (characterized by an elevated mood and excessive energy and optimism) and develop bipolar disorder, according to the APA.

Major depression is commonly associated with other conditions, including eating disorders (e.g., anorexia nervosa, bulimia nervosa), anxiety disorders (e.g., obsessive-compulsive disorder) and borderline personality disorder. In addition, about one in three depressed patients also suffers from some form of substance abuse or dependence, according to the NMHA. Depressed patients may also experience more pain and general physical illnesses and are at a higher risk of developing chronic conditions such as coronary artery disease.

Major depression affects those close to the patient, as well. Adult first-degree biological relatives (e.g., brothers, sisters) may have an increased risk of alcoholism. The children of patients with major depression may have an increased risk of an anxiety disorder or attention deficit hyperactivity disorder.

Major depression is one of the leading causes of disability in the United States and internationally, according to the World Health Organization.

Risk factors and causes of major depression

The cause of major depression cannot be narrowed down to a single factor. However, it appears that brain chemistry plays a major role in the disorder. Brain chemicals called neurotransmitters convey messages between the nerves. Too many or too few neurotransmitters, particularly norepinephrine, serotonin and dopamine, are believed to cause alterations in mood.

There are many risk factors for major depression. For instance, women are nearly twice as likely to develop major depression as men. Many mental health professionals believe that hormonal changes during pregnancy, miscarriage, menstruation, the postpartum period, premenopause and menopause may lead to a major depressive episode.

Individuals with a personal or family history of depression are also at greater risk of developing the condition. Heredity may influence women’s risk of developing the disorder more so than men, according to a recent study on twins. People who have had one episode of major depression have a 60 percent chance of having another episode. According to the National Alliance on Mental Illness (NAMI), the risk of major depression may be as high as 25 percent in first-degree relatives (e.g., parents, children, siblings) of patients with a history of major depression.

Other risk factors for major depression include:

  • Stressful events or life situations. Individuals who have experienced major stresses, such as the death or prolonged absence of a loved one, divorce, discrimination, abuse or trauma, have an increased risk of major depression. Unrealistic or unreachable expectations or life goals or major obstacles (real or perceived) to life goals and expectations may also increase the risk of major depression.

  • Chronic physical medical conditions. The rate of major depression among patients hospitalized for general medical illnesses is between 10 and 14 percent, according to the National Mental Health Association (NMHA). The more severe the condition, the greater the risk of major depression. Relatives, especially children, of chronically ill or hospitalized patients may also be at an increased risk for major depression. Medical conditions of particular concern include:

    • Heart disease. According to the NMHA, about 18 to 20 percent of patients with coronary disease who have not had a heart attack may be majorly depressed and as many as 40 to 65 percent of heart attack survivors may have major depression.

    • Stroke. The NMHA reports that as many as 10 to 27 percent of stroke survivors may experience major depression for about a year.

    • Diabetes. The risk of major depression in patients with adult onset diabetes is as high as 25 percent, according to the NMHA. In addition, as many as 70 percent of patients with diabetic complications, such as kidney failure, may be majorly depressed.

    • Cancer. An estimated one in four people with cancer are majorly depressed, according to the NMHA.

    • Nutritional deficiency. Several studies report that the vitamin B12 level and major depression may be positively associated. Further, replacement of vitamin B12 may increase the probability of recovery from depression.

In addition, conditions such as hypothyroidism (low levels of the thyroid hormone) and anemia (deficiency of red blood cells and/or hemoglobin) may mimic the symptoms of depression and can be misdiagnosed as major depression.

  • Medication use. Numerous medications can produce side effects that include symptoms of depression.

  • Other mental health conditions. People with other mental health conditions, such as some eating disorders and some anxiety disorders, are more likely to experience major depression.

  • Substance abuse. People who abuse alcohol, drugs or other substances have an increased risk of major depression. The likelihood of suffering major depression also seems to be increased among cigarette smokers, especially those who smoke heavily.

  • Marital status, quality of marriage and lack of social supports. In general, married people have a lower risk of major depression. However, unhappily married people have a much higher risk of the disorder. Individuals who feel rejected or depreciated by a loved one, or who have few or no friends, are also at an increased risk for major depression.

  • Negative patterns of thinking. Individuals who tend to think negatively are at an increased risk of major depression.

Signs and symptoms of major depression

The signs and symptoms of major depression may vary greatly among patients. Generally, there are nine primary symptoms of depression, which include:

  • Sad or depressed mood. The patient may experience profound sadness, anxiety, anger, irritability or apathy (lack of emotion). He or she may be pessimistic or discouraged and may experience crying spells or excessive emotional sensitivity.

  • Anhedonia. Reduction or loss of interest in activities the patient formerly found pleasurable, such as eating, sex, work, friends, hobbies and entertainment.

  • Significant change in appetite or weight. The patient may experience reduced or increased appetite or significant weight loss or gain.

  • Changes in sleep patterns. The patient may sleep too much (hypersomnia) or not enough (insomnia). The patient will often awaken early in the morning and have difficulty falling back asleep.

  • Physical or verbal activity. Patients may be agitated and anxious. They may wring their hands, pace or not be able to sit still. Conversely, patients may have sluggish movements or speech. There may be a pause before answering questions or starting actions. Patients may speak quietly or not be able to be heard. They may not speak except in response to a direct question or may become completely mute (not talking at all).

  • Fatigue and decreased energy level.

  • Self-worth. The patient may have feelings of worthlessness, self-reproach or excessive or inappropriate guilt.

  • Concentration. The patient may exhibit a diminished ability to think or concentrate.

  • Death thoughts. Patients may have recurrent thoughts of death and death wishes. They may think about committing suicide (suicidal ideation) or engage in suicidal actions. Patients may even attempt or complete suicide.

People who have major depression may not initially seek treatment for their mood, but may instead see their primary physician to treat what they believe is a physical disorder. Fatigue, headache and stomach pains that do not respond to medication are often reported. Irritability rather than profound sadness is also common. Older adults may appear confused.

Major depression is common in children and adolescents. However, young people may not be willing to express their emotions to an adult, or may not know how to do so. In addition, it may be difficult to differentiate symptoms of depression from some accepted adolescent behaviors. Because of this, it is important to watch for signs that a child or adolescent may be depressed. These signs include:

  • Missing or refusing to go to school

  • Poor performance in school

  • Complaints of boredom

  • Changes in eating and sleeping habits

  • Withdrawal from friends and activities that used to be enjoyed

  • Problems with authority

  • Overreaction to criticism

  • Frequent physical complaints (e.g., headaches, stomachaches)

  • Pattern of dark images or themes or excessive aggression toward the self or others in drawings, painting, poetry and other forms of expression

Diagnosis methods for major depression

Before major depression can be diagnosed, a physician will typically perform a physical examination to rule out other conditions that may be causing symptoms. Many people who are eventually diagnosed with major depression visit their primary care physician first because they suspect there is a physical problem. However, a mental health professional can also diagnose major depression.

Diagnosis of major depression typically begins with a complete medical history, including information about the onset, duration and severity of symptoms. The physician or mental health professional will also ask whether the patient has experienced these symptoms before and, if so, whether and how they were treated and whether treatment was effective. The patient will also be asked about alcohol and drug use, whether they have thought about death or suicide and whether other family members have had depression or other mental illnesses. If there is a family history of depression, the practitioner will ask how it was treated. A diagnostic evaluation may also be performed. This examination of the patient’s mental status determines if memory, speech or thought patterns have been affected. A blood analysis should also be performed to rule out some medical conditions (e.g., anemia, thyroid disease, low vitamin B12 levels) which cause symptoms similar to those of depression.

Despite being a serious and common disorder, major depression is highly under-diagnosed for many reasons. Some people believe there is a stigma attached to seeking help for any potential mental health condition. Major depression may be overlooked in pregnancy and many medical conditions with similar symptoms. Diagnosis in adolescents may be difficult because many adults may expect moodiness in teens. Men may be more reluctant to seek treatment or talk about emotional problems.

The American Psychiatric Association (APA) lists strict criteria for the diagnosis of major depression. These criteria include altered mood or loss of interest or pleasure in activities that were once enjoyed (anhedonia), as well as other specific symptoms and the duration of those symptoms. The symptoms include at least five of the following:

  • Substantial change in appetite or weight
  • Too little or too much sleep
  • Observable agitation or sluggishness in activity
  • Fatigue
  • Reduced feelings of self-worth
  • Problems with concentration
  • Thoughts about death or suicide

Symptoms that can be explained by a general medical condition, or those due to other diagnosed mental disorders, are not considered in the diagnosis of major depression. For instance, fatigue or weight change due to a medical problem or procedure would not be considered as symptoms of major depression.

The symptoms of major depression are present for most of the day, nearly every day, for at least two weeks. In addition, major depression is diagnosed when the symptoms are severe enough to interfere with normal life.

Treatment and prevention of major depression

According to the National Institute of Mental Health (NIMH), more than 80 percent of people with major depression can be treated successfully with psychotherapy, medical therapy or a combination of both. However, up to 50 percent may not respond to initial treatment. The treatment options available for major depression are quite varied and individualized. Mild forms of the disorder may respond well to psychotherapy alone, whereas moderate to severe forms typically require medication treatment (e.g., antidepressants). The outcome of treatment is generally best with a combination of psychotherapy and medication. During treatment, the patient’s mood will improve gradually, with the patient feeling a little better each day.

Some forms of psychotherapy that may be effective in the treatment of major depression include:

  • Cognitive behavioral therapy. Attempts to change negative patterns of thought or behavior that are associated with depression and teach the patient to achieve more satisfaction and rewards from their own actions.

  • Interpersonal therapy. Focuses on the patient’s personal relationships and the problems in these relationships that cause or worsen depression. A form of interpersonal therapy, family therapy, involves the entire family and may be particularly helpful when there are specific family-related stresses.

  • Psychodynamic therapy. Focuses on resolving the conflict in a patient’s feelings, such as the desire for praise coupled with feelings of worthlessness. This therapy is often reserved until symptoms are significantly improved.

Medications for major depression offer relief of symptoms over a period of time. The primary medications for this disorder are antidepressants, and may include:

  • Selective serotonin reuptake inhibitors (SSRIs). These newer antidepressants increase the level of serotonin in the brain.

  • Tricyclic antidepressants (TCAs). Alter the levels of several chemicals in the brain.

  • Monoamine oxidase inhibitors (MAOIs). The first antidepressants used, although less commonly used today.

  • Serotonin and norepinephrine reuptake inhibitors. Affect several brain chemicals and may be effective in cases where other antidepressants are not.

In 2006, The U.S. Food and Drug Administration (FDA) approved the first antidepressant skin patch (selegiline) for the treatment of major depression. The patch works by releasing medication directly into the bloodstream through the skin. Although it is a type of MAOI, patients using the lowest available dose of the selegiline patch (6 milligrams every 24 hours) will not have to adhere to specific dietary regulations as they would with all other drugs in this class. Traditional MAOIs cannot be combined with certain foods and beverages (e.g., aged cheeses, wine) because a sharp spike in blood pressure, known as a “hypertensive crisis,” may occur. This severe event is typically characterized by symptoms such as nausea, sudden and severe headache, stiff neck, rapid heartbeat or change in pattern of heartbeat (palpitations), confusion and sweating.

Antidepressants typically take several weeks for full effects and are generally taken for at least four to nine months, or even indefinitely, to prevent recurrence. Patients should be aware that a physician may need to adjust the dosage or change medications to achieve the best results with minimal side effects. In addition, the FDA has advised that antidepressants may increase the risk of suicidal thinking in some patients and all people being treated with them should be monitored closely for unusual changes in behavior.

Other medications may be used in combination with antidepressants in some cases. These are generally not effective when taken alone for major depression. Anti-anxiety drugs and lithium are among the most commonly used medications combined with antidepressants for major depression. When the patient is displaying psychotic features, antipsychotics may be used. Stimulants, such as amphetamines, are not usually effective with antidepressants, but may be used under close monitoring in medically ill patients with major depression.

Herbal and dietary supplements (e.g., St. John’s wort) may also be used to treat major depression, although their effectiveness has not been established. It is important for patients to speak with a physician before taking any herbal or dietary supplement because many supplements cause serious drug interactions or have other serious side effects. For instance, St. John’s wort has been shown to induce mania in people with bipolar disorder.

Exercise, particularly aerobic activity, has been shown to have positive antidepressant effects in individuals with mild to moderate depression. Patients are generally encouraged to at least try to exercise.

In rare cases, electroconvulsive therapy, or ECT, may be recommended by some physicians to treat severe depression in patients who cannot take medications (e.g., pregnant women) or who do not respond to medications. ECT is a controversial treatment in which electrical current is used to cause a brief convulsion in the patient. ECT appears to provide some short-term benefits, but its long-term effectiveness versus its potential side effects (e.g., confusion, memory loss) is not clear. Some experts recommend ECT only as a last resort, when medication and other therapy are not effective or cannot help the patient quickly enough.

For some people, major depression may not be preventable. A healthy lifestyle that includes a balanced diet and exercise and strong social and interpersonal connections may help. People who have experienced major depression and recognize the return of their symptoms can seek help immediately to minimize their effect.

Questions for your doctor on major depression

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about major depression:

  1. How can I distinguish between sadness and major depression?
  2. How can I tell if a friend or loved one has major depression?
  3. Are there any medical disorders that could cause my depression symptoms?
  4. Are the symptoms I’ve been experiencing characteristic of major depression?
  5. What type of therapy is most appropriate for me?
  6. Will my entire family participate in my therapy?
  7. Will my treatment include an antidepressant?
  8. Which antidepressant do you recommend for me?
  9. What side effects are associated with the medications you are recommending for me?
  10. For how long will I have to take medications?
  11. How soon after starting treatment will I see improvement in my condition?
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