Depression or depressive disorder is an illness that involves the body, mood, and thoughts. Depression is considered a mood disorder. Imbalances in three neurotransmitters (brain chemicals), including serotonin, norepinephrine, and dopamine, are linked to depression. Depression affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about life situations. Unlike normal emotional experiences of sadness, loss, or passing mood states, depressive disorders are persistent and can significantly interfere with an individual's thoughts, behavior, mood, activity, and physical health.
According to the National Institute of Mental Health (NIMH), depressive disorders affect approximately 18.8 million American adults or about 9.5% of the U.S. population age 18 and older in a given year. This includes major depressive disorder (severe depression), dysthymic disorder (mild to moderate depression), and bipolar disorder (manic-depressive). Among all medical illnesses, major depression is the leading cause of disability in the U.S. and many other developed countries.
Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people who suffer from depression.
Children and teenagers can also suffer from depression. Depression in the young is defined as an illness when the feelings of depression persist and interfere with a child or adolescent's ability to function.
The American Academy of Child and Adolescent Psychiatry estimates that about 5% of children and adolescents in the general population suffer from depression at any given point in time. Children under stress, who experience loss, or who have trouble with attention, learning, conduct, or anxiety disorders are at a higher risk for depression.
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types of depression
Major depression: This type of depression lasts more than two weeks. Symptoms may include overwhelming feelings of sadness and grief, loss of interest or pleasure in activities usually enjoyed, and feelings of worthlessness or guilt. This type of depression may result in poor sleep, a change in appetite, severe fatigue and difficulty concentrating. Severe depression may increase the risk of suicide.
Atypical depression: Individuals with atypical depression, as opposed to major depression, experience improved mood when something good happens. In addition, two of the following symptoms occur to have atypical depression: an increase in appetite or weight gain (as opposed to the reduced appetite or weight loss of "typical" depression), excessive sleeping (as opposed to insomnia), leaden paralysis (a severe form of fatigue or tiredness), and sensitivity to rejection.
Dysthymia: Dysthymia is a less severe depression (mild to moderate) than major but a more chronic form of depression. Signs and symptoms usually are not disabling, and periods of mild depression can alternate with short periods of feeling normal. Having dysthymia places an individual at an increased risk of major depression. To be considered having dysthymia, the first two years of depressed mood cannot include any episodes of major depression. In addition, no underlying cause of depressed mood, such as a general medical condition (PMS, menopause, or coronary heart disease) or substance abuse may be present. The symptoms of dysthymia and the associated signs of depression cause significant distress or impairment in social, occupational, and other important areas of functioning. When a major depressive episode occurs on top of dysthymia, healthcare professionals may refer to the resultant condition as double depression.
Adjustment disorders: Having a loved one die, losing a job, or receiving a diagnosis of cancer or another disease can cause an individual to feel tense, sad, overwhelmed, or angry. Eventually, most people come to terms with the lasting consequences of life stresses, but some do not; this is called an adjustment disorder. Adjustment disorders are forms of depression that occur when the response to a stressful event or situation causes signs and symptoms of depression. Some people develop an adjustment disorder in response to a single event such as a parent or spouse dying. In others, it stems from a combination of stressors. Adjustment disorders can be acute (lasting less than six months) or chronic (lasting longer). Doctors classify adjustment disorders based on the primary signs and symptoms of depression.
Bipolar disorder: Having recurrent episodes of depression and elation (mania) is characteristic of bipolar disorder. Because this condition involves emotions at both extremes (poles), it's called bipolar disorder or manic-depressive disorder. Mania affects judgment, causing individuals to make unwise decisions. Some people have bursts of increased creativity and productivity during the manic phase. The number of episodes at either extreme may not be equal. Some people may have several episodes of depression before having another manic phase, or vice versa.
Seasonal affective disorder: Seasonal affective disorder (SAD) is a pattern of depression related to changes in seasons and a lack of exposure to sunlight. SAD usually occurs in winter. It may cause headaches, irritability and a low energy level. SAD is not a chronic (long term) depressive disorder.
Postpartum depression: According to the American College of Obstetricians and Gynecologists, about 10% of new moms experience postpartum depression, a more severe form of depression that can develop within the first six months after giving birth. For women with postpartum depression, feelings such as sadness, anxiety and restlessness can be so strong that they interfere with daily tasks. Rarely, a more extreme form of depression known as postpartum psychosis can develop. Symptoms of this psychosis include a fear of harming oneself or one's baby, confusion and disorientation, hallucinations and delusions, and paranoia.
Premenstrual dysphoric disorder (PMDD): PMDD occurs when depressive symptoms, such as crying, tiredness, and sadness, occur one week prior to menstruation and disappear after menstruation.