| Major depression is a serious psychiatric illness that negatively affects how an individual feels, thinks, and acts. It is one of several types of depression: reactive depression, the most common depressive state, resulting from reaction to illness or grief; bipolar or manic-depressive disorder, the least common depression characterized by episodes of mania and depression; and major or “endogenous” (arising from biological causes) depression, representing one-quarter of all cases of depression and attributed to genetic or biochemical causes. Major depression is responsible for more physical and social dysfunction than many chronic medical conditions. Individuals with major depression find it difficult to cope with normal life activities or to feel or enjoy the pleasures of life.
Everyone experiences depressed moods as a result of a change, either in the form of a setback or a loss. The sadness and depressed feelings that accompany the changes and losses of life are usually appropriate, necessary, and transitory and can present an opportunity for personal growth. However, depression that persists and results in serious dysfunction in daily life may indicate a depressive disorder that may need to be treated as a medical problem. The severity, duration, and presence of other symptoms are factors that distinguish normal sadness from a depressive disorder.
Major depression, known as major depressive disorder in the DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision), is a mood disorder distinguished by the occurrence of one or more major depressive episodes. A major depressive episode is diagnosed when an individual experiences persistent feelings of sadness or anxiety, with loss of interest or pleasure in usual activities (anhedonia). In addition, five or more of the following symptoms must be present for at least two consecutive weeks: changes in appetite that result in weight losses or gains unrelated to dieting; insomnia or oversleeping; loss of energy or increased fatigue; restlessness or irritability; feelings of worthlessness or inappropriate guilt; difficulty thinking, concentrating, or making decisions; and thoughts of death or suicide, or attempts at suicide. A cause or trigger for major depression may not be identified in all individuals. However, genetic predisposition and/or disturbances in levels of the neurotransmitters serotonin, dopamine, and norepinephrine are believed to be the underlying metabolic abnormalities in most cases.
Grief is a psychological and emotional reaction to a significant loss, including the loss of a spouse or loved one; grieving may lead to reactive depression from which the individual recovers uneventfully, or it can result in bereavement-related depression (BRD), a major depressive episode. Early bereavement-related responses may be disbelief, low mood, insomnia, and loss of appetite, accompanied by disrupted functioning. At one month after experiencing loss of a loved one, about 40% of individuals seeking medical care meet the criteria for major depression (Hensley). However, the DSM-IV-TR suggests not diagnosing bereavement-related depression until at least two months have passed after the loved one’s death. At two months, about 24% of grieving individuals meet the criteria for major depression, and at one year, about 15% (Hensley).
A depressive episode is diagnosed only if the symptoms described above are not associated with any other psychiatric conditions (such as bipolar disorder) or medical conditions (such as neurological or hormonal problems, cancer, or an individual's state of health after a stroke or a heart attack). In the latter case, the diagnosis is mood disorder due to a general medical condition, the general medical condition to be particularly specified. To be diagnostic for major depression, symptoms must not be due to side effects of medications or substance abuse.
The DSM-IV-TR divides major depressive disorder into two subtypes based on whether the individual has experienced a single depressive episode or recurrent depressive episodes. The DSM-IV-TR also adds specifiers to a diagnosis, rating severity along a continuum of mild, moderate, severe, and severe with psychotic features. The latter is sometimes known as depressive psychosis. Partial and full remissions are additional specifiers for major depressive episodes.Risk: According to the DSM-IV-TR, anyone of any age, race, class, or gender can experience depression. It is estimated that up to 25% of individuals experiencing severe medical conditions (e.g., endocrine, neurological, or vascular conditions) will experience a concurrent major depressive disorder. Major risk factors are female sex, age, family history, bereavement, brain injury, and a history of previous depression. Women suffer from the disorder at least twice as often as men in societies around the world. The peak ages of onset are between 20 and 25 years and between 40 and 45 years. Although older individuals frequently seek treatment, there is no evidence that major depression is more common in older than in younger adults. Individuals who have parents or siblings with major depression have a greater risk (1.5 to 3 times) of developing this disorder. Grief is a risk factor because it may turn into major depression, especially in bereaved spouses, who often meet the criteria for major depression (Hensley). Incidence and Prevalence: Depression of all types affects 10% of the population; one-quarter of depressed individuals are diagnosed with major depression. In the US, the lifetime risk is 10% to 25% for women and 5% to 12% for men. An international study (17 researchers and 38,000 individuals from 10 countries) reported that the lifetime risk of depression ranged from 1.5% in Taiwan to 19% in Lebanon. Risks in other countries, in ascending order, were 2.9% in Korea, 4.3% in Puerto Rico, 5.2% in the US, 9.2% in Germany, 9.6% in Canada, 11.6% in New Zealand, and 16.4% in France (Weissman). The point prevalence (one-time occurrence) and lifetime prevalence of major depression were shown to be 2.7% and 9.6% in men over age 65 and 4.4% and 20.4% in women over age 65, respectively (Steffens). The exact prevalence is not known, however, since only one-third of adults experiencing depression seek treatment (Steffens). |