Wednesday, December 8, 2010

Colds and Flu

hi readers :) in this article i'll to tell you . something about "Colds and Flu" . hopefully useful . and enrich your knowledge . happy reading :)
You start sneezing. Your throat gets sore and scratchy. You have to blow your nose a lot. You don’t feel very well. Do you have cold? Or do you have the flu?
Colds and flu are illnesses caused by germs. They are both caused by germs called viruses. But they are caused by different kinds of viruses. Colds are often called common colds. Flu is short for influenza.

IS IT A COLD OR THE FLU?

Signs that you have a cold or the flu are called symptoms. The symptoms of a cold and the symptoms of the flu are slightly different.

The symptoms of a cold are sore throat, cough, sneezing, and a stuffy, runny nose. Colds usually do not cause a fever.

Flu symptoms are like cold symptoms, but the flu also causes chills, fever, and headaches. It makes you feel tired and achy all over.

A cold or the flu usually lasts about a week. Every once in a while they can lead to a more serious sickness, such as an ear infection or a lung infection called pneumonia.

CATCHING A COLD OR THE FLU

People once thought you could catch a cold from getting a chill in cold weather. They thought that wet feet or drafts of cold air could give you a cold.

We now know that germs cause colds and flu. The germs are passed from one person to another. They travel in coughs and sneezes.

More colds and cases of flu happen in cold weather because people spend more time together indoors when it’s cold outside. It is easier for germs to spread when people are close together.

IS THERE A CURE?

There is no cure for the common cold. People take medicine to help their sore throats, coughs, and runny noses. Doctors say that resting in bed is the best way to treat a cold.

There is no cure for the flu, either. Doctors can give medicine to make you feel better. Resting in bed and drinking lots of juice and water is the best way to treat the flu.

AVOIDING A COLD OR THE FLU

You can get a flu shot to help keep you from catching the flu. A flu shot, or vaccination, helps your body fight off flu germs if they attack. But it doesn’t always work. The flu virus keeps changing. When it changes, the old vaccine no longer works. Doctors have to keep making new vaccines. For this reason, you need a new flu shot every year. Sometimes the flu changes enough in a single year that you can still catch it even if you’ve been vaccinated.

There is no vaccine against the common cold because more than 100 different kinds of viruses cause colds. These viruses also keep changing.

One thing you can do to protect against cold and flu germs is wash your hands before you eat anything or touch your face. Your hands may pick up the germs from door knobs or other things touched by someone with a cold. Washing your hands thoroughly kills the germs.

You can also try not to spread germs when you have a cold or the flu. Use tissues when you sneeze. Cover your mouth when you cough. And wash your hands frequently to keep from spreading cold germs to others.
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Monday, December 6, 2010

Diabetes Mellitus

hi readers, in this article i'll to tell you something about "Diabetes Mellitus" . hopefully useful and can enrich your knowledge :) happy reading :D

I INTRODUCTION

Diabetes Mellitus, disease in which the pancreas produces insufficient amounts of insulin, or in which the body’s cells fail to respond appropriately to insulin. Insulin is a hormone that helps the body’s cells absorb glucose (sugar) so it can be used as a source of energy.

In people with diabetes, glucose levels build up in the blood and urine, causing excessive urination, thirst, hunger, and problems with fat and protein metabolism. Diabetes mellitus differs from the less common diabetes insipidus, which is caused by lack of the hormone vasopressin, which controls the amount of urine secreted.
In the United States, some 21 million people (7 percent of the population) suffer from diabetes mellitus. Every year, some 1.5 million people learn they have the disease. Diabetes mellitus kills more than 73,000 U.S. residents each year, making it the sixth leading cause of all deaths resulting from disease. In addition, diabetes is a contributing factor in many deaths from heart disease, kidney failure, and other conditions. Overall, experts estimate that diabetes contributes to about 225,000 deaths annually in the United States. In Canada, approximately 2.5 million residents (about 6 percent of the population) have diabetes mellitus. The disease ranks as the seventh leading cause of death in Canada, where it kills about 6,000 people a year. Diabetes and its complications contribute to about 25,000 deaths in Canada annually.
Diabetes is most common in adults over 45 years of age; in people who are overweight or physically inactive; in individuals who have an immediate family member with diabetes; and in people of African, Hispanic, and Native American descent. The highest rate of diabetes in the world occurs in Native Americans. More women than men have been diagnosed with the disease.
In diabetes mellitus low insulin levels or poor response to insulin prevent cells from absorbing glucose. As a result, glucose builds up in the blood. When glucose-laden blood passes through the kidneys, the organs that remove blood impurities, the kidneys cannot absorb all of the excess glucose. This excess glucose spills into the urine, accompanied by water and electrolytes—ions required by cells to regulate the electric charge and flow of water molecules across the cell membrane. This causes frequent urination to get rid of the additional water drawn into the urine; excessive thirst to trigger replacement of lost water; and hunger to replace the glucose lost in urination. Additional symptoms may include blurred vision, dramatic weight loss, irritability, weakness and fatigue, and nausea and vomiting. 

II TYPE 1 DIABETES

Diabetes is classified into two types. In Type 1 diabetes, formerly called insulin-dependent diabetes mellitus (IDDM) and juvenile-onset diabetes, the body does not produce insulin or produces it only in very small quantities. Symptoms usually appear suddenly, typically in individuals under 20 years of age. Most cases occur around puberty—around age 10 to 12 in girls and age 12 to 14 in boys. In the United States Type 1 diabetes accounts for 5 to 10 percent of all diabetes cases. In Canada, Type 1 diabetes accounts for about 10 percent of all diabetes cases.
Type 1 diabetes is a disease in which the body produces too little insulin or no insulin at all. In most cases, Type 1 diabetes is an autoimmune disease, that is, a condition in which the body’s disease-fighting immune system goes awry and attacks healthy tissues. In the case of Type 1 diabetes, the immune system mistakenly attacks and destroys insulin-producing cells, known as beta cells, in the pancreas. Scientists believe that a combination of genetic and environmental factors somehow triggers the immune system to destroy these cells. Scientists have so far identified 20 genes that play a role in Type 1 diabetes, although the exact function of these genes is still under investigation. Environmental factors, such as certain viruses, may also contribute to the development of the disease, particularly in people who already have a genetic predisposition for the disease. Type 1 diabetes also can result from surgical removal of the pancreas.
In addition to causing a buildup of glucose in the blood, untreated Type 1 diabetes affects the metabolism of fat. Because the body cannot convert glucose into energy, it begins to break down stored fat for fuel. This produces increasing amounts of acidic compounds in the blood called ketone bodies, which interfere with cellular respiration, the energy-producing process in cells. 

III TYPE 2 DIABETES

In Type 2 diabetes, formerly known as non-insulin-dependent diabetes mellitus (NIDDM) and adult-onset diabetes, the body’s delicate balance between insulin production and the ability of cells to use insulin goes awry. Symptoms characteristic of Type 2 diabetes include those found in Type 1 diabetes, as well as repeated infections or skin sores that heal slowly or not at all, generalized tiredness, and tingling or numbness in the hands or feet.
Of the nearly 21 million people in the United States with diabetes, 90 to 95 percent have Type 2 diabetes. About 90 percent of all diabetes cases in Canada are Type 2. The onset of Type 2 diabetes usually occurs after the age of 45, although the incidence of the disease in younger people is growing rapidly. Because symptoms develop slowly, individuals with the disease may not immediately recognize that they are sick. A number of genes are involved in Type 2 diabetes. In addition, there is a strong relationship between obesity and Type 2 diabetes. About 80 percent of diabetics with this form of the disease are significantly overweight.

IV COMPLICATIONS
 
If left untreated, diabetes mellitus may cause life-threatening complications. Type 1 diabetes can result in diabetic coma (a state of unconsciousness caused by extremely high levels of glucose in the blood) or death. In both Type 1 and Type 2 diabetes, complications may include blindness, kidney failure, and heart disease. Diabetes can cause tiny blood vessels to become blocked; when this occurs in blood vessels of the eye, it can result in retinopathy (the breakdown of the lining at the back of the eye), causing blindness. Diabetes mellitus is the leading cause of new cases of blindness in people aged 20 to 74. In the kidneys, diabetes can lead to nephropathy (the inability of the kidney to properly filter toxins from the blood). About 40 percent of new cases of end-stage renal disease (kidney failure) are caused by diabetes mellitus. Blockages of large blood vessels in diabetics can lead to many cardiovascular problems, including high blood pressure, heart attack, and stroke. Although these conditions also occur in nondiabetic individuals, people with diabetes are two to four times more likely to develop cardiovascular disorders.
Diabetes mellitus may also cause loss of feeling, particularly in the lower legs. This numbness may prevent a person from feeling the pain or irritation of a break in the skin or of foot infection until after complications have developed, possibly necessitating amputation of the foot or leg. Burning pain, sensitivity to touch, and coldness of the foot, conditions collectively known as neuropathy, can also occur. Other complications include higher-risk pregnancies in diabetic women and a greater occurrence of dental disease.

V DIAGNOSIS AND TREATMENT
 
Diabetes is detected by measuring the amount of glucose in the blood after an individual has fasted (abstained from food) for about eight hours. In some cases, physicians diagnose diabetes by administering an oral glucose tolerance test, which measures glucose levels before and after a specific amount of sugar has been ingested.
Once diabetes is diagnosed, treatment consists of controlling the amount of glucose in the blood and preventing complications. Depending on the type of diabetes, this can be accomplished through regular physical exercise, a carefully controlled diet, and medication.
Individuals with Type 1 diabetes must receive insulin, often two to four times a day, to provide the body with the hormone it does not produce. Insulin cannot be taken orally, because it is destroyed in the digestive system. Consequently, insulin-dependent diabetics have historically injected the drug using a hypodermic needle or a beeper-sized pump connected to a needle inserted under the skin. In 2006 the United States Food and Drug Administration approved a form of insulin that can be inhaled and then is absorbed by blood in the lungs.
The amount of insulin needed varies from person to person and may be influenced by factors such as a person’s level of physical activity, diet, and the presence of other health disorders. Typically, individuals with Type 1 diabetes use a meter several times a day to measure the level of glucose in a drop of their blood obtained by pricking a fingertip. They can then adjust the dosage of insulin, physical exercise, or food intake to maintain the blood sugar at a normal level. People with Type 1 diabetes must carefully control their diets by distributing meals and snacks throughout the day so as not to overwhelm the ability of the insulin supply to help cells absorb glucose. They also need to eat foods that contain complex sugars, which break down slowly and cause a slower rise in blood sugar levels.
Although most persons with Type 1 diabetes strive to lower the amount of glucose in their blood, levels that are too low can also cause health problems. For example, if a person with Type 1 diabetes takes too much insulin, it can produce low blood sugar levels. This may result in hypoglycemia, a condition characterized by shakiness, confusion, and anxiety. A person who develops hypoglycemia can combat symptoms by ingesting glucose tablets or by consuming foods with high sugar content, such as fruit juices or hard candy.
In order to control insulin levels, people with Type 1 diabetes must monitor their glucose levels several times a day. In 1983 a group of 1,441 Type 1 diabetics aged 13 to 39 began participating in the Diabetes Control and Complications Trial (DCCT), the largest scientific study of diabetes treatment ever undertaken. The DCCT studied the potential for reducing diabetes-related complications, such as nerve or kidney disease or eye disorders, by having patients closely monitor their blood sugar levels four to six times a day, maintaining the levels as close to normal as possible. The results of the study, reported in 1993, showed a 50 to 75 percent reduction of diabetic complications in people who aggressively monitored and controlled their glucose levels. Although the study was performed on people with Type 1 diabetes, researchers believe that close monitoring of blood sugar levels would also benefit people with Type 2 diabetes.
For persons with Type 2 diabetes, treatment begins with diet control, exercise, and weight reduction, although over time this treatment may not be adequate. People with Type 2 diabetes typically work with nutritionists to formulate a diet plan that regulates blood sugar levels so that they do not rise too swiftly after a meal. A recommended meal is usually low in fat (30 percent or less of total calories), provides moderate protein (10 to 20 percent of total calories), and contains a variety of carbohydrates, such as beans, vegetables, and grains. Regular exercise helps body cells absorb glucose—even ten minutes of exercise a day can be effective. Diet control and exercise may also play a role in weight reduction, which appears to partially reverse the body’s inability to use insulin.
For some people with Type 2 diabetes, diet, exercise, and weight reduction alone may work initially, but eventually this regimen does not help control high blood sugar levels. In these cases, oral medication may be prescribed. If oral medications are ineffective, a person with Type 2 diabetes may need insulin doses or a combination of oral medication and insulin. About 50 percent of individuals with Type 2 diabetes require oral medications, 40 percent require insulin or a combination of insulin and oral medications, and 10 percent use diet and exercise alone. 

VI CURRENT RESEARCH
 
At present no cure exists for diabetes, and scientists are unsure of the exact cause, although researchers are investigating a combination of genetic and environmental factors. So far researchers have identified 20 genes involved in Type 1 diabetes, and they are working to determine each gene’s role in causing the disease. The inheritance patterns of Type 1 diabetes are complicated, with many different genes influencing a person’s risk. For instance, a gene known as DR plays a role in Type 1 diabetes. Two forms of this gene, called DR3 and DR4, are present in 95 percent of people with Type 1 diabetes. People who inherit DR3 alone develop diabetes at an older age and have antibodies that destroy insulin-producing beta cells. Those who inherit DR4 tend to develop diabetes earlier in life and have antibodies that destroy insulin. A person with both DR3 and DR4 typically develops diabetes at a very young age and has the highest level of insulin-destroying antibodies.
In 2000 researchers were surprised to find that a variation of a gene called Caplain-10, which is not involved in glucose metabolism, is associated with the development of Type 2 diabetes. One form of this gene produces a small amount of protein, and researchers are studying how this decrease in protein increases a person’s risk for diabetes. Other genetic studies indicate that certain genes cause a variation of Type 2 diabetes called maturity onset diabetes of the young (MODY), which develops in people under the age of 25. Although scientists do not yet understand how these genes cause MODY, the genes are known to be active in the liver, intestine, kidney, and pancreas.
Other scientists hope to identify the environmental factors that trigger Type 1 diabetes in people with a genetic predisposition for the disease. If they can determine what causes the immune system to attack the cells that produce insulin, they may discover how to prevent the condition from developing. For instance, studies suggest that certain viruses, such as coxsackie B, rubella, and mumps, may trigger an immune reaction against beta cells or in some cases directly infect and destroy these cells.
Researchers attribute most cases of Type 2 diabetes to obesity. Studies show that the risk for developing Type 2 diabetes increases by 4 percent for every pound of excess weight a person carries. Researchers are investigating the exact role that extra weight plays in preventing the proper utilization of insulin and why some overweight people develop the disease while others do not.
Research also focuses on transplanting a healthy pancreas or its insulin-producing beta cells into a person with Type 1 diabetes to provide a natural source of insulin. Some patients who have received pancreas transplants have experienced considerable improvements in their health, but positive, long-term results with beta-cell transplants have not yet occurred. In both types of transplants recipients must take drugs that suppress their immune systems so the body will not reject the new pancreas or cells. These drugs can cause life-threatening side effects because the patient’s body can no longer protect itself from other harmful substances. In most people with diabetes, these drugs pose a greater risk to health than living with diabetes. Scientists are also studying the development of an artificial pancreas and ways to genetically manipulate non-insulin-producing cells into making insulin.
New methods for accurately measuring blood glucose levels may improve the quality of life for many individuals with diabetes. New techniques include the use of laser beams and infrared technology. For example, a tiny computer using infrared light can be used to measure a person’s blood sugar level. The computer automatically delivers the reading to an insulin pump carried on the diabetic’s body that injects the appropriate amount of insulin.
Other advances include new drugs that control blood sugar. In April 2000 the United States Food and Drug Administration (FDA) approved glargine, an insulin drug that needs to be injected only once a day. Sold under the brand name Lantus, this drug can be used by people with Type 1 diabetes, as well as by those with Type 2 diabetes who require insulin injections. And, as mentioned earlier, in 2006 the FDA approved a form of insulin that can be inhaled. Physicians have long known that some insulin-dependent diabetics fail to take the drug as often as needed because of the discomfort of injections. Doctors hoped the inhalant form of insulin would lead to better patient compliance.
A number of drugs have been developed to help people with Type 2 diabetes. Examples include acarbose, (sold under the brand name Precose), which controls blood sugar by slowing the digestion of carbohydrates; and metformin (sold under the brand name Glucophage), which controls liver production of sugar, causes weight loss, and reduces total cholesterol. Pioglitazone (brand name, Actos) and rosiglitazone (brand name, Avandia) are drugs that make the cells more sensitive to insulin. A study published in 2007 found that Avandia increases the risk of heart attacks. Soon afterward the FDA told the manufacturers of Avandia and Actos, which had also been shown to carry a heart risk, to add prominent safety warnings to the drugs’ labels.
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Saturday, December 4, 2010

Depression (psychology)

hi readers,, in this article i'll to tell you something about "Depression (psychology)" hopefully useful. happy reading :)
I INTRODUCTION

Depression (psychology), mental illness in which a person experiences deep, unshakable sadness and diminished interest in nearly all activities. People also use the term depression to describe the temporary sadness, loneliness, or blues that everyone feels from time to time.

In contrast to normal sadness, severe depression, also called major depression, can dramatically impair a person’s ability to function in social situations and at work. People with major depression often have feelings of despair, hopelessness, and worthlessness, as well as thoughts of committing suicide.

Depression can take several other forms. In bipolar disorder, sometimes called manic-depressive illness, a person’s mood swings back and forth between depression and mania. People with seasonal affective disorder typically suffer from depression only during autumn and winter, when there are fewer hours of daylight. In dysthymia (pronounced dis-THI-mee-uh), people feel depressed, have low self-esteem, and concentrate poorly most of the time—often for a period of years—but their symptoms are milder than in major depression. Some people with dysthymia experience occasional episodes of major depression. Mental health professionals use the term clinical depression to refer to any of the above forms of depression.

Surveys indicate that people commonly view depression as a sign of personal weakness, but psychiatrists and psychologists view it as a real illness. In the United States, the National Institute of Mental Health has estimated that depression costs society many billions of dollars each year, mostly in lost work time.

II PREVALENCE

Depression is one of the most common mental illnesses. At least 8 percent of adults in the United States experience serious depression at some point during their lives, and estimates range as high as 17 percent. The illness affects all people, regardless of sex, race, ethnicity, or socioeconomic standing. However, women are two to three times more likely than men to suffer from depression. Experts disagree on the reason for this difference. Some cite differences in hormones, and others point to the stress caused by society’s expectations of women.

Depression occurs in all parts of the world, although the pattern of symptoms can vary. The prevalence of depression in other countries varies widely, from 1.5 percent of people in Taiwan to 19 percent of people in Lebanon. Some researchers believe methods of gathering data on depression account for different rates.

A number of large-scale studies indicate that depression rates have increased worldwide over the past several decades. Furthermore, younger generations are experiencing depression at an earlier age than did previous generations. Social scientists have proposed many explanations, including changes in family structure, urbanization, and reduced cultural and religious influences.

III SYMPTOMS

Although it may appear anytime from childhood to old age, depression usually begins during a person’s 20s or 30s. The illness may come on slowly, then deepen gradually over months or years. On the other hand, it may erupt suddenly in a few weeks or days. A person who develops severe depression may appear so confused, frightened, and unbalanced that observers speak of a “nervous breakdown.” However it begins, depression causes serious changes in a person’s feelings and outlook. A person with major depression feels sad nearly every day and may cry often. People, work, and activities that used to bring them pleasure no longer do.

Symptoms of depression can vary by age. In younger children, depression may include physical complaints, such as stomachaches and headaches, as well as irritability, “moping around,” social withdrawal, and changes in eating habits. They may feel unenthusiastic about school and other activities. In adolescents, common symptoms include sad mood, sleep disturbances, and lack of energy. Elderly people with depression usually complain of physical rather than emotional problems, which sometimes leads doctors to misdiagnose the illness.

Symptoms of depression can also vary by culture. In some cultures, depressed people may not experience sadness or guilt but may complain of physical problems. In Mediterranean cultures, for example, depressed people may complain of headaches or nerves. In Asian cultures they may complain of weakness, fatigue, or imbalance.

If left untreated, an episode of major depression typically lasts eight or nine months. About 85 percent of people who experience one bout of depression will experience future episodes.

A Appetite and Sleep Changes

Depression usually alters a person’s appetite, sometimes increasing it, but usually reducing it. Sleep habits often change as well. People with depression may oversleep or, more commonly, sleep for fewer hours. A depressed person might go to sleep at midnight, sleep restlessly, then wake up at 5 am feeling tired and blue. For many depressed people, early morning is the saddest time of the day.

B Changes in Energy Level

Depression also changes one’s energy level. Some depressed people may be restless and agitated, engaging in fidgety movements and pacing. Others may feel sluggish and inactive, experiencing great fatigue, lack of energy, and a feeling of being worn out or carrying a heavy burden. Depressed people may also have difficulty thinking, poor concentration, and problems with memory.

C Poor Self-Esteem

People with depression often experience feelings of worthlessness, helplessness, guilt, and self-blame. They may interpret a minor failing on their part as a sign of incompetence or interpret minor criticism as condemnation. Some depressed people complain of being spiritually or morally dead. The mirror seems to reflect someone ugly and repulsive. Even a competent and decent person may feel deficient, cruel, stupid, phony, or guilty of having deceived others. People with major depression may experience such extreme emotional pain that they consider or attempt suicide. At least 15 percent of seriously depressed people commit suicide, and many more attempt it.

D Psychotic Symptoms

In some cases, people with depression may experience psychotic symptoms, such as delusions (false beliefs) and hallucinations (false sensory perceptions). Psychotic symptoms indicate an especially severe illness. Compared to other depressed people, those with psychotic symptoms have longer hospital stays, and after leaving, they are more likely to be moody and unhappy. They are also more likely to commit suicide. See Psychosis.

IV CAUSES


Some depressions seem to come out of the blue, even when things are going well. Others seem to have an obvious cause: a marital conflict, financial difficulty, or some personal failure. Yet many people with these problems do not become deeply depressed. Most psychologists believe depression results from an interaction between stressful life events and a person’s biological and psychological vulnerabilities.

A Biological Factors

Depression runs in families. By studying twins, researchers have found evidence of a strong genetic influence in depression. Genetically identical twins raised in the same environment are three times more likely to have depression in common than fraternal twins, who have only about half of their genes in common. In addition, identical twins are five times more likely to have bipolar disorder in common. These findings suggest that vulnerability to depression and bipolar disorder can be inherited. Adoption studies have provided more evidence of a genetic role in depression. These studies show that children of depressed people are vulnerable to depression even when raised by adoptive parents.

Genes may influence depression by causing abnormal activity in the brain. Studies have shown that certain brain chemicals called neurotransmitters play an important role in regulating moods and emotions. Neurotransmitters involved in depression include norepinephrine, dopamine, and serotonin. Research in the 1960s suggested that depression results from lower than normal levels of these neurotransmitters in parts of the brain. Support for this theory came from the effects of antidepressant drugs, which work by increasing the levels of neurotransmitters involved in depression. However, later studies have discredited this simple explanation and have suggested a more complex relationship between neurotransmitter levels and depression.

An imbalance of hormones may also play a role in depression. Many depressed people have higher than normal levels of hydrocortisone (cortisol), a hormone secreted by the adrenal gland in response to stress. In addition, an underactive or overactive thyroid gland can lead to depression.

A variety of medical conditions can cause depression. These include dietary deficiences in vitamin B6, vitamin B12, and folic acid (see Vitamin); degenerative neurological disorders, such as Alzheimer’s disease and Huntington’s disease (see Chorea); strokes in the frontal part of the brain; and certain viral infections, such as hepatitis and mononucleosis. Certain medications, such as steroids, may also cause depression.

B Psychological Factors

Psychological theories of depression focus on the way people think and behave. In a 1917 essay, Austrian psychoanalyst Sigmund Freud explained melancholia, or major depression, as a response to loss—either real loss, such as the death of a spouse, or symbolic loss, such as the failure to achieve an important goal. Freud believed that a person’s unconscious anger over loss weakens the ego, resulting in self-hate and self-destructive behavior.

Cognitive theories of depression emphasize the role of irrational thought processes. American psychiatrist Aaron Beck proposed that depressed people tend to view themselves, their environment, and the future in a negative light because of errors in thinking. These errors include focusing on the negative aspects of any situation, misinterpreting facts in negative ways, and blaming themselves for any misfortune. In Beck’s view, people learn these self-defeating ways of looking at the world during early childhood. This negative thinking makes situations seem much worse than they really are and increases the risk of depression, especially in stressful situations.

In support of this cognitive view, people with “depressive” personality traits appear to be more vulnerable than others to actual depression. Examples of depressive personality traits include gloominess, pessimism, introversion, self-criticism, excessive skepticism and criticism of others, deep feelings of inadequacy, and excessive brooding and worrying. In addition, people who regularly behave in dependent, hostile, and impulsive ways appear at greater risk for depression.

American psychologist Martin Seligman proposed that depression stems from “learned helplessness,” an acquired belief that one cannot control the outcome of events. In this view, prolonged exposure to uncontrollable and inescapable events leads to apathy, pessimism, and loss of motivation. An adaptation of this theory by American psychologist Lynn Abramson and her colleagues argues that depression results not only from helplessness, but also from hopelessness. The hopelessness theory attributes depression to a pattern of negative thinking in which people blame themselves for negative life events, view the causes of those events as permanent, and overgeneralize specific weaknesses as applying to many areas of their life.

C Stressful Events

Psychologists agree that stressful experiences can trigger depression in people who are predisposed to the illness. For example, the death of a loved one may trigger depression. Psychologists usually distinguish true depression from grief, a normal process of mourning a loved one who has died. Other stressful experiences may include divorce, pregnancy, the loss of a job, and even childbirth. About 20 percent of women experience an episode of depression, known as postpartum depression, after having a baby. In addition, people with serious physical illnesses or disabilities often develop depression.

People who experience child abuse appear more vulnerable to depression than others. So, too, do people living under chronically stressful conditions, such as single mothers with many children and little or no support from friends or relatives.

V TREATMENT

Depression typically cannot be shaken or willed away. An episode must therefore run its course until it weakens either on its own or with treatment. Depression can be treated effectively with antidepressant drugs, psychotherapy, or a combination of both.

Despite the availability of effective treatment, most depressive disorders go untreated and undiagnosed. Studies indicate that general physicians fail to recognize depression in their patients at least half of the time. In addition, many doctors and patients view depression in elderly people as a normal part of aging, even though treatment for depression in older people is usually very effective.

A Antidepressant Drugs

Up to 70 percent of people with depression respond to antidepressant drugs. These medications appear to work by altering the levels of serotonin, norepinephrine, and other neurotransmitters in the brain. They generally take at least two to three weeks to become effective. Doctors cannot predict which type of antidepressant drug will work best for any particular person, so depressed people may need to try several types. Antidepressant drugs are not addictive, but they may produce unwanted side effects. To avoid relapse, people usually must continue taking the medication for several months after their symptoms improve.

Commonly used antidepressant drugs fall into three major classes: tricyclics, monoamine oxidase inhibitors (MAO inhibitors), and selective serotonin reuptake inhibitors (SSRIs). Tricyclics, named for their three-ring chemical structure, include amitriptyline (Elavil), imipramine (Tofanil), desipramine (Norpramin), doxepin (Sinequan), and nortriptyline (Pamelor). Side effects of tricyclics may include drowsiness, dizziness upon standing, blurred vision, nausea, insomnia, constipation, and dry mouth.

MAO inhibitors include isocarboxazid (Marplan), phenelzine (Nardil), and tranylcypromine (Parnate). People who take MAO inhibitors must follow a diet that excludes tyramine—a substance found in wine, beer, some cheeses, and many fermented foods—to avoid a dangerous rise in blood pressure. In addition, MAO inhibitors have many of the same side effects as tricyclics.

Selective serotonin reuptake inhibitors include fluoxetine (Prozac), sertraline (Zoloft), and paroxetine (Paxil). These drugs generally produce fewer and milder side effects than do other types of antidepressants, although SSRIs may cause anxiety, insomnia, drowsiness, headaches, and sexual dysfunction. Some patients have alleged that Prozac causes violent or suicidal behavior in a small number of cases, but the U.S. Food and Drug Administration has failed to substantiate this claim.

Prozac became the most widely used antidepressant in the world soon after its introduction in the late 1980s by drug manufacturer Eli Lilly and Company. Many people find Prozac extremely effective in lifting depression. In addition, some people have reported that Prozac actually tranforms their personality by increasing their self-confidence, optimism, and energy level. However, mental health professionals have expressed serious ethical concerns over Prozac’s use as a “personality enhancer,” especially among people without clinical depression.

Doctors often prescribe lithium carbonate, a natural mineral salt, to treat people with bipolar disorder (see Lithium). People often take lithium during periods of relatively normal mood to delay or even prevent subsequent mood swings. Side effects of lithium include nausea, stomach upset, vertigo, and frequent urination.

B Psychotherapy

Studies have shown that short-term psychotherapy can relieve mild to moderate depression as effectively as antidepressant drugs. Unlike medication, psychotherapy produces no physiological side effects. In addition, depressed people treated with psychotherapy appear less likely to experience a relapse than those treated only with antidepressant medication. However, psychotherapy usually takes longer to produce benefits.

There are many kinds of psychotherapy. Cognitive-behavioral therapy assumes that depression stems from negative, often irrational thinking about oneself and one’s future. In this type of therapy, a person learns to understand and eventually eliminate those habits of negative thinking. In interpersonal therapy, the therapist helps a person resolve problems in relationships with others that may have caused the depression. The subsequent improvement in social relationships and support helps alleviate the depression. Psychodynamic therapy views depression as the result of internal, unconscious conflicts. Psychodynamic therapists focus on a person’s past experiences and the resolution of childhood conflicts. Psychoanalysis is an example of this type of therapy. Critics of long-term psychodynamic therapy argue that its effectiveness is scientifically unproven.

C Other Treatments

Electroconvulsive therapy (ECT) can often relieve severe depression in people who fail to respond to antidepressant medication and psychotherapy. In this type of therapy, a low-voltage electric current is passed through the brain for one to two seconds to produce a controlled seizure. Patients usually receive six to ten ECT treatments over several weeks. ECT remains controversial because it can cause disorientation and memory loss. Nevertheless, research has found it highly effective in alleviating severe depression.

For milder cases of depression, regular aerobic exercise may improve mood as effectively as psychotherapy or medication. In addition, some research indicates that dietary modifications can influence one’s mood by changing the level of serotonin in the brain.

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