Major depression



Major depressive disorder (also known as major depression, unipolar depression, unipolar disorder, or clinical depression) is a mental disorder typically characterized by a pervasive low mood, low self-esteem, and loss of interest or pleasure in usual activities. The term was coined by the American Psychiatric Association in the 1980 version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III) classification for the symptom cluster, and has become widely used. The general term depression is often used to describe the disorder, but since it is also used to describe a temporary sad or depressed mood, more precise terminology is preferred in clinical use and research. Major depression is often a disabling condition which adversely affects a person's family, work or school life, sleeping and eating habits, and general health. In the United States around 3.4% of people with major depression commit suicide, and up to 60% of all people who commit suicide have depression or another mood disorder.

Symptoms and signs
According to the National Institute of Mental Health, major depression is a serious illness that affects a person's family, work or school life, sleeping and eating habits, and general health. The impact of depression on functioning and well-being has been equated to that of chronic medical conditions such as diabetes.

A person suffering a major depressive episode usually experiences a pervasive low mood, or loss of interest or pleasure in favored activities. Depressed people may be preoccupied with feelings of worthlessness, inappropriate guilt or regret, helplessness or hopelessness. Other symptoms include poor concentration and memory, withdrawal from social situations and activities, reduced libido (sex drive), and thoughts of death or suicide. Insomnia is common: in the typical pattern, a person wakes very early and is unable to get back to sleep. Hypersomnia, or oversleeping, is less common. Appetite often decreases, with resulting weight loss, although increased appetite and weight gain occasionally occur. The person may report persistent physical symptoms such as fatigue, headaches, digestive problems, or chronic pain; this is a typical presentation of depression, according to the World Health Organization's criteria of depression, in developing countries. Family and friends may perceive that the person is either agitated or slowed down. Older people with depression are more likely to show cognitive symptoms of recent onset, such as forgetfulness and to show a more noticeable slowing of movements. In severe cases, depressed people may experience psychotic symptoms such as delusions or, less commonly, hallucinations, usually of an unpleasant nature.

Children may display an irritable rather than depressed mood, and show different symptoms depending on age and situation. Most exhibit a loss of interest in school and a decline in academic performance. Children with depression may be described as clingy, demanding, dependent, or insecure. Diagnosis may be delayed or missed when symptoms are interpreted as normal moodiness.

Clinical assessment
A diagnostic assessment may be conducted by a general practitioner or by a psychiatrist or psychologist, who will record the person's current circumstances, biographical history and current symptoms, and a family medical history to see if other family members have suffered from a mood disorder, and discuss the person's alcohol and drug use. A mental state examination includes an assessment of the person's current mood and an exploration of thought content, in particular the presence of themes of hopelessness or pessimism, self-harm or suicide, and an absence of positive thoughts or plans. Specialist mental health services are rare in rural areas, and thus diagnosis and management is largely left to primary care clinicians. This issue is even more marked in developing countries.

Before diagnosing a major depressive disorder, a doctor generally performs a medical examination and selected investigations to rule out other causes of symptoms. These include blood tests measuring TSH to exclude hypo- or hyperthyroidism; basic electrolytes and serum calcium to rule out a metabolic disturbance; and a full blood count including ESR to rule out a systemic infection or chronic disease. Testosterone levels may be used to diagnose hypogonadism, a cause of depression in men. Subjective cognitive complaints appear in older depressed people, but they can also be indicative of the onset of a dementing disorder, such as Alzheimer's disease. Depression is also a common initial symptom of dementia. Conducted in older depressed people, screening tests such as the mini-mental state examination, or a more complete neuropsychological evaluation, can rule out cognitive impairment. A CT scan can exclude brain pathology in those with psychotic, rapid-onset or otherwise unusual symptoms. No biological tests confirm major depression. Investigations are not generally repeated for a subsequent episode unless there is a specific medical indication, in which case serum sodium can rule out hyponatremia (low sodium) if the person presents with increased frequency of passing urine, a common side-effect of selective serotonin reuptake inhibitor antidepressants.

Rating scales
Depression screening measures are not used to diagnose the condition, but they provide an indication of the severity of symptoms for a time period, so a person who scores above a given a cut-off point can be more thoroughly evaluated for a depressive disorder diagnosis. Several rating scales are used for this purpose. The Hamilton Depression Rating Scale and the Montgomery-Åsberg Depression Rating Scale. are the two most commonly used among those completed by clinicians. The Beck Depression Inventory is the most commonly used tool completed by patients, although scales completed by observers are more common. The Geriatric Depression Scale is a self-administered scale used in older populations and also valid in patients with mild to moderate dementia. The Patient Health Questionnaires (PHQ) are two self-administered questionnaires for use in primary care. The PHQ-2 has two screening questions about the frequency of depressed mood and a loss of interest in activities; a positive to either question indicates further testing is required. The PHQ-9 is a slightly more detailed nine-question survey for assessing symptoms of major depressive disorder in greater detail, and is often used to follow up a positive PHQ-2 test. Screening programs have been advocated to improve detection of depression, but there is evidence that the use of screening instruments does little to improve detection rates, treatment, or outcome.

DSM-IV-TR and ICD-10 criteria
The most widely used criteria for diagnosing depressive conditions are found in the American Psychiatric Association's revised fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), and the World Health Organization's International Statistical Classification of Diseases and Related Health Problems (ICD-10) which uses different terminology, calling a similar condition "Recurrent depressive disorder". The latter system is typically used in European countries, while the former is used in the US and many other non-European nations.

Major depressive disorder is classified as a mood disorder in DSM-IV-TR. The diagnosis hinges on the presence of a single or recurrent major depressive episode. Further qualifiers are used to classify both the episode itself and the course of the disorder. The category Depressive disorder not otherwise specified is diagnosed if the depressive episode's manifestation does not meet the criteria for a major depressive episode. The ICD-10 system does not use the term Major depressive disorder, but lists similar criteria for the diagnosis of a depressive episode (mild, moderate or severe); the term recurrent may be added if there have been multiple episodes without mania.

Major depressive episode
A major depressive episode is characterized by the presence of a severely depressed mood that persists for at least two weeks. Episodes may be isolated or recurrent and are categorized as mild (few symptoms in excess of minimum criteria), moderate, or severe (marked impact on social or occupational functioning). An episode with psychotic features&mdash;commonly referred to as psychotic depression&mdash;is automatically rated as severe. If the patient has had an episode of mania or markedly elevated mood, a diagnosis of bipolar disorder is made instead. Depression without mania is sometimes referred to as unipolar because the mood remains at one emotional state or "pole". DSM-IV-TR excludes cases where the symptoms are a result of bereavement, although it is possible for normal bereavement to evolve into a depressive episode if the mood persists and the characteristic features of a major depressive episode develop. The criteria have been criticized because they do not take into account any other aspects of the personal and social context in which depression can occur. In addition, some studies have found little empirical support for the DSM-IV cut-off criteria, indicating they are a diagnostic convention imposed on a continuum of depressive symptoms of varying severity and duration: excluded are a range of related diagnoses, including dysthymia which involves a chronic but milder mood disturbance, Recurrent brief depression which involves briefer depressive episodes, Minor depressive disorder which involves only some of the symptoms of major depression, and Adjustment disorder with depressed mood which involves low mood resulting from a psychological response to an identifiable event or stressor.

Subtypes
The DSM-IV-TR recognizes several subtypes, which are sometimes called "course specifiers":


 * Atypical depression is characterized by mood reactivity (paradoxical anhedonia) and positivity, significant weight gain or increased appetite (comfort eating), excessive sleep or sleepiness (hypersomnia), a sensation of heaviness in limbs known as leaden paralysis, and significant social impairment as a consequence of hypersensitivity to perceived interpersonal rejection.


 * Catatonic depression is a rare and severe form of major depression involving disturbances of motor behavior and other symptoms. Here the person is mute and almost stuporose, and either remains immobile or exhibits purposeless or even bizarre movements. Catatonic symptoms also occur in schizophrenia or in manic episodes, or may be caused by neuroleptic malignant syndrome.


 * Melancholic depression is characterized by a loss of pleasure in most or all activities, a failure of reactivity to pleasurable stimuli, a quality of depressed mood more pronounced than that of grief or loss, a worsening of symptoms in the morning hours, early morning waking, psychomotor retardation, excessive weight loss (not to be confused with anorexia nervosa), or excessive guilt.

Other types of depression, not categorized as Major depressive disorder, are recognized by the DSM-IV-TR:
 * Postpartum depression (Mild mental and behavioral disorders associated with the puerperium, not elsewhere classified in ICD-10 ) refers to the intense, sustained and sometimes disabling depression experienced by women after giving birth. Postpartum depression, which has incidence rate of 10–15% among new mothers, typically sets in within three months of labor, and lasts as long as three months.


 * Seasonal affective disorder is a form of depression in which depressive episodes come on in the autumn or winter, and resolve in spring. The diagnosis is made if at least two episodes have occurred in colder months with none at other times, over a two-year period or longer.

Other ways of categorizing depression have been used historically and they include:
 * Anaclitic depression
 * Dysthymic disorder
 * Endogenous depression
 * Involutional depression
 * Reactive depression
 * Recurrent depression
 * Treatment resistant depression

Differential diagnoses
In order to decide that major depressive disorder is the most likely diagnosis, the probability of several other potential diagnoses must be considered, including the following:


 * Dysthymia is a chronic, milder mood disturbance in which a person reports a low mood almost daily over a span of at least two years. The symptoms are not as severe as those for major depression, although people with dysthymia are vulnerable to secondary episodes of major depression (sometimes referred to as double depression).


 * Adjustment disorder with depressed mood is a mood disturbance appearing as a psychological response to an identifiable event or stressor, in which the resulting emotional or behavioral symptoms are significant but do not meet the criteria for a major depressive episode.


 * Bipolar disorder, previously known as manic-depressive disorder, is a condition in which depressive phases alternate with periods of mania or hypomania. Although depression is currently categorized as a separate disorder, there is ongoing debate because individuals diagnosed with major depression often experience some hypomanic symptoms, indicating a mood disorder continuum.

Treatment
The three most common treatments for depression are psychotherapy, medication, and electroconvulsive therapy. Psychotherapy is the treatment of choice for people under 18, while electroconvulsive therapy is only used as a last resort. Care is usually given on an outpatient basis, while treatment in an inpatient unit is considered if there is a significant risk to self or others.

Treatment options are much more limited in developing countries, where access to mental health staff, medication, and psychotherapy is often difficult. Development of mental health services is minimal in many countries; depression is viewed as a phenomenon of the developed world despite evidence to the contrary, and not as an inherently life-threatening condition.

Psychotherapy
Psychotherapy can be delivered, to individuals or groups, by mental health professionals, including psychotherapists, psychiatrists, psychologists, clinical social workers, counselors, and psychiatric nurses. With more complex and chronic forms of depression, the most effective treatment is often considered to be a combination of medication and psychotherapy. In people under 18, medication is usually offered only in conjunction with psychotherapy, not as a first line treatment. Psychotherapy has been shown to be effective in older people. Successful psychotherapy appears to prevent the recurrence of depression even after it has been terminated or replaced by occasional booster sessions. The same degree of prevention can be achieved by continuing antidepressant treatment.

The most studied form of psychotherapy for depression is cognitive behavioral therapy (CBT), thought to work by teaching clients to learn a set of useful cognitive and behavioral skills. Earlier research suggested that cognitive-behavioral therapy was not as effective as antidepressant medication; however, more recent research suggests that it can perform as well as antidepressants in patients with moderate to severe depression. Overall, systematic review reveals CBT to be an effective treatment in depressed adolescents, although possibly not for severe episodes. Combining fluoxetine with CBT appeared to bring no additional benefit or, at the most, only marginal benefit.

A review of studies on the effectiveness of Mindfulness-based Cognitive Therapy (MBCT), a recently developed class-based program designed to prevent relapse, suggests that MBCT may have an additive effect when provided with the usual care in patients who have had three or more depressive episodes, although the usual care did not include antidepressant treatment or any psychotherapy, and the improvement observed may have reflected non-specific or placebo effects.

Interpersonal psychotherapy focuses on the social and interpersonal triggers that may cause depression. There is evidence that it is an effective treatment. Here, the therapy takes a structured course with a set number of weekly sessions (often 12) as in the case of CBT, however the focus is on relationships with others. Therapy can be used to help a person develop or improve interpersonal skills in order to allow him or her to communicate more effectively and reduce stress.

Psychoanalysis, a school of thought founded by Sigmund Freud that emphasizes the resolution of unconscious mental conflicts, is used by its practitioners to treat clients presenting with major depression. A more widely practiced, eclectic technique, called psychodynamic psychotherapy, is loosely based on psychoanalysis and has an additional social and interpersonal focus. In a meta-analysis of three controlled trials of Short Psychodynamic Supportive Psychotherapy, this modification was found to be as effective as medication for mild to moderate depression.

Sociocultural aspects


Even today, people's conceptualizations of depression vary widely, both within and among cultures. "Because of the lack of scientific certainty," one commentator has observed, "the debate over depression turns on questions of language. What we call it—'disease,' 'disorder,' 'state of mind'—affects how we view, diagnose, and treat it." There are cultural differences in the extent to which serious depression is considered an illness requiring personal professional treatment, or is an indicator of something else, such as the need to address social or moral problems, the result of biological imbalances, or a reflection of individual differences in the understanding of distress that may reinforce feelings of powerlessness, and emotional struggle.

The diagnosis is less common in some countries, such as China. It has been argued that the Chinese traditionally deny or somatize emotional depression (although since the early 1980s the Chinese denial of depression may have modified drastically). Alternatively, it may be that Western cultures reframe and elevate some expressions of human distress to disorder status. Australian professor Gordon Parker and others have argued that the Western concept of depression "medicalizes" sadness or misery. There has also been concern that the DSM, as well as the field of descriptive psychiatry that employs it, tends to reify abstract phenomena such as depression, which may in fact be social constructs. American archetypal psychologist James Hillman writes that depression can be healthy for the soul, insofar as "it brings refuge, limitation, focus, gravity, weight, and humble powerlessness." Hillman argues that therapeutic attempts to eliminate depression echo the Christian theme of resurrection, but have the unfortunate effect of demonizing a soulful state of being.

There has been a continuing discussion of whether neurological disorders and mood disorders may be linked to creativity,  a discussion that goes back to Aristotelian times. British literature gives many examples of reflections on depression. English philosopher John Stuart Mill experienced a several-months-long period of what he called "a dull state of nerves," when one is "unsusceptible to enjoyment or pleasurable excitement; one of those moods when what is pleasure at other times, becomes insipid or indifferent". He quoted English poet Samuel Taylor Coleridge's "Dejection" as a perfect description of his case: "A grief without a pang, void, dark and drear, / A drowsy, stifled, unimpassioned grief, / Which finds no natural outlet or relief / In word, or sigh, or tear." English writer Samuel Johnson used the term "the black dog" in the 1780s to describe his own depression, and it was subsequently popularized by depression sufferer former British Prime Minister Sir Winston Churchill.



Historical figures were often reluctant to discuss or seek treatment for depression due to social stigma about the condition, or due to ignorance of diagnosis or treatments. Nevertheless, analysis or interpretation of letters, journals, artwork, writings or statements of family and friends of some historical personalities has led to the presumption that they may have had some form of depression. People who may have had depression include American-British writer Henry James and American president Abraham Lincoln. Some well-known contemporary people with possible depression include Canadian songwriter Leonard Cohen and American playwright and novelist Tennessee Williams. Some pioneering psychologists, such as Americans William James and John B. Watson, dealt with depression in their adulthoods.

Both William James and John Stuart Mill found relief from their depression in literature. For James, who was nearly driven to suicide during his depression, the choice to believe in free will was instrumental in overcoming this condition. This choice was inspired by an essay about free will by French philosopher Charles-Bernard Renouvier. Upon reading this essay, James no longer felt that "suicide [was] the most manly form to put [his] daring into," and declared, "now I will go a step further with my will, not only act with it, but believe as well; believe in my individual reality and creative power." Mill took solace in the work of English poet William Wordsworth. Mill wrote that, "What made Wordsworth's poems a medicine for my state of mind, was that they expressed, not mere outward beauty, but states of feeling, and of thought coloured by feeling, under the excitement of beauty."

Social stigma of major depression is widespread, and contact with mental health services reduces this only slightly. Public opinions on treatment differ markedly to those of health professionals; alternative treatments are held to be more helpful than pharmacological ones, which are viewed poorly. The Royal College of Psychiatrists and the Royal College of General Practitioners conducted a joint Five-year Defeat Depression campaign to educate and reduce stigma from 1992 to 1996; a MORI study conducted afterwards showed a small positive change in public attitudes to depression and treatment.

History of the disorder
Depression is the modern terminology for what in earlier times was described as Melancholia. As early as the 4th and 5th centuries BC, Melancholia was described as "aversion to food, despondency, sleeplessness, irritability, restlessness," as well as the statement that "Grief and fear, when lingering, provoke melancholia". It is now generally believed that melancholia was the same phenomenon as what is now called clinical depression.

Depression - Causes
Major depression is generally seen as a mental disorder with multiple causes. The understanding of the nature and causes of depression has evolved over the centuries; nevertheless, many aspects of depression are still not fully understood, and are the subject of debate and research. Both psychological and biological causes have been proposed. Psychological theories and treatments are based on ideas about the personality, interpersonal communication, and unduly negative thoughts. The monoamine chemicals serotonin, norepinephrine, and dopamine are naturally present in the brain and assist communication between nerve cells. Monoamines have been implicated in depression, and most antidepressants work to increase the active levels of at least one.

Biology of depression
Most antidepressants increase synaptic levels of serotonin, one of a group of neurotransmitters known as monoamines. Serotonin is thought to help regulate other neurotransmitter systems, and decreased serotonin activity may allow these systems to act in unusual and erratic ways. According to this "permissive hypothesis," depression can arise when low serotonin levels promote low levels of norepinephrine, another monoamine neurotransmitter. Some antidepressants also enhance the levels of norepinephrine directly, whereas others raise the levels of dopamine, a third monoamine neurotransmitter. These observations gave rise to the monoamine theory of depression. In its contemporary formulation, the monoamine theory postulates that a deficiency of certain neurotransmitters is responsible for the corresponding features of depression: "Norepinephrine may be related to alertness and energy as well as anxiety, attention, and interest in life; [lack of] serotonin to anxiety, obsessions, and compulsions; and dopamine to attention, motivation, pleasure, and reward, as well as interest in life." The proponents of this theory recommend choosing the antidepressant with the mechanism of action impacting the most prominent symptoms. Anxious and irritable patients should be treated with SSRIs or norepinephrine reuptake inhibitors, and those experiencing a loss of energy and enjoyment of life with norepinephrine and dopamine enhancing drugs.

In the past two decades, research has uncovered multiple limitations of the monoamine theory, and its inadequacy has been criticized within the psychiatric community. Intensive investigation has failed to find convincing evidence of a primary dysfunction of a specific monoamine system in patients with major depressive disorders. The medications tianeptine and opipramol have long been known to have antidepressant properties despite not acting through the monoamine system. Experiments with pharmacological agents that cause depletion of monoamines have shown that this depletion does not cause depression in healthy people nor does it worsen symptoms in depressed patients. According to an essay published by the Public Library of Science, the monoamine theory, already limited, has been further oversimplified when presented to the general public.

MRI scans of patients with depression have reported a number of differences in brain structure compared to those without the illness. Although there is some inconsistency in the results, meta-analyses have shown there is strong evidence for smaller hippocampal volumes and increased numbers of hyperintensive lesions. Hyperintensities have been associated with patients with a late age of onset, and have led to the development of the theory of vascular depression.

There may be a link between depression and neurogenesis of the hippocampus, a center for both mood and memory. Loss of hippocampal neurons is found in some depressed individuals and correlates with impaired memory and dysthymic mood. Drugs may increase serotonin levels in the brain, stimulating neurogenesis and thus increasing the total mass of the hippocampus. This increase may help to restore mood and memory. Similar relationships have been observed between depression and an area of the anterior cingulate cortex implicated in the modulation of emotional behavior. One of the neurotrophins responsible for neurogenesis is the brain-derived neurotrophic factor (BDNF). The level of BDNF in the blood plasma of depressed subjects is drastically reduced (more than threefold) as compared to the norm. Antidepressant treatment increases the blood level of BDNF. Although decreased plasma BDNF levels have been found in many other disorders, there is some evidence that BDNF is involved in the cause of depression and the mechanism of action of antidepressants.

Major depression may also be caused in part by an overactive hypothalamic-pituitary-adrenal axis (HPA axis) that is similar to the neuro-endocrine response to stress. Investigations reveal increased levels of the hormone cortisol, enlarged pituitary and adrenal glands, and a blunted circadian rhythm. Oversecretion of corticotropin-releasing hormone from the hypothalamus is thought to drive this, and is implicated in the cognitive and arousal symptoms. The REM stage of sleep, in which dreaming occurs, tends to be especially quick to arrive, and especially intense, in depressed people. Although the precise relationship between sleep and depression is mysterious, the relationship appears to be particularly strong among those whose depressive episodes are not precipitated by stress. In such cases, patients may be especially unaffected by therapeutic intervention.

The hormone estrogen has been implicated in depressive disorders due to the increase in risk of depressive episodes after puberty, the antenatal period, and reduced rates after menopause. Conversely, the premenstrual and postpartum periods of low estrogen levels are also associated with increased risk. The use of estrogen has been under-researched, and there although some small trials show promise in its use to prevent or treat depression, the evidence for its effectiveness is not strong. Estrogen replacement therapy has been shown to be beneficial in improving mood in perimenopause, but it is unclear if it is merely the menopausal symptoms that are being reversed.

==Psychological factors in depression

Psychological theories of depression
Various aspects of personality and its development are integral in the occurrence and persistence of depression. Although episodes are strongly correlated with adverse events, how a person copes with stress also plays a role. Low self-esteem, learned helplessness, and self-defeating or distorted thinking are related to depression. Depression may also be connected to feelings of religious alienation; conversely, depression is less likely to occur among those with high levels of religious involvement. It is not always clear which factors are causes or effects of depression, but in any case depressed persons who are able to make corrections in their thinking patterns often show improved mood and self-esteem.

Cognitive psychologists and cognitive behavioral therapists have theorized that depression arises from cognitive biases and distortions stemming from deficits in memory and information processing. According to American psychologist Martin Seligman, depression in humans is similar to learned helplessness in laboratory animals, who remain in unpleasant situations when they are able to escape, but do not because they initially learned they had no control. Learned helplessness and depression may be related to what American psychologist Julian Rotter, a social learning theorist, called an external locus of control, a tendency to attribute outcomes to events outside of personal control. American psychiatrist, Aaron T. Beck, proposed that a triad of negative thoughts, Beck's cognitive triad, are present in depression entailing cognitive errors about oneself, one's world, and one's future.

On the other hand, depressed individuals often blame themselves for negative events. According to one study, depressed adolescents, while feeling responsible for negative events, do not take credit for positive outcomes. This tendency is characteristic of a depressive attributional, or pessimistic explanatory style. According to Canadian social psychologist, Albert Bandura, who is associated with Social cognitive theory, depressed individuals have  negative perceptions of themselves, including a negative self-concept and perceived  lack a sense of self-efficacy; in other words they do not believe they can influence events or  achieve personal goals. Milder depression has been associated with what has been called depressive realism, or the "sadder-but-wiser" effect, a view of the world that is relatively undistorted by positive biases.

A large body of research has documented the importance of interpersonal factors, including strained or critical personal relationships, in the onset of depressive symptoms and depression in young and middle-aged adults. Vulnerability factors—such as early maternal loss, lack of a confiding relationship, responsibility for the care of several young children at home, and unemployment—can interact with life stressors to increase the risk of depression in women. However, the validity of risk factors has been widely debated. For older adults, the factors are often health problems, changes in relationships with a spouse or adult children due to the transition to a care-giving or care-needing role, the death of a significant other, or a change in the availability or quality of social relationships with older friends because of their own health-related life changes.

Austrian psychiatrist Sigmund Freud, the father of psychoanalysis, likened the state of melancholia to mourning in his 1917 paper Mourning and Melancholia. He theorized that objective loss, such as the loss of a valued relationship through death or a romantic break-up, results in subjective loss as well; the depressed individual has identified with the object of affection through an unconscious, narcissistic process called the libidinal cathexis of the ego. Such loss results in severe melancholic symptoms more profound than mourning; not only is the outside world viewed negatively, but the ego itself is compromised. The patient's decline of self-regard is revealed in his belief of his own blame, inferiority, and unworthiness.

Generally grouped together, existential and humanistic approaches represent a forceful affirmation of individualism. Austrian existential psychiatrist Viktor Frankl connected depression to feelings of futility and meaninglessness. American existential psychologist Rollo May stated that "depression is the inability to construct a future". In general, May wrote, "depression...occur[s] more in the dimension of time than in space," and the depressed individual fails to look ahead in time properly. Thus the "focusing upon some point in time outside the depression...gives the patient a perspective, a view on high so to speak; and this may well break the chains of the...depression." Humanistic psychologists argue that depression can result from an incongruity between society and the individual's innate drive to self-actualize, or to realize one's full potential. American humanistic psychologist Abraham Maslow theorized that depression is especially likely to arise when the world precludes a sense of "richness" or "totality" for the self-actualizer.

Social factors in depression
Poverty and social isolation are associated with increased risk of psychiatric problems in general; a study in Providence, Rhode Island following children from birth found that family disruption and low socioeconomic status in early childhood were linked to an increased risk of major depression in later life; this was noted to be independent of later adult social status and related to various social inequalities, the consequences of which may be more severe for women. Childhood emotional, physical, sexual abuse, or neglect are also associated with increased risk of developing depressive disorders later in life. Disturbances in family functioning, such as parental (particularly maternal) depression, severe marital conflict or divorce, death of a parent, or other disturbances in parenting are additional risk factors.

In adulthood, stressful life events are strongly associated with the onset of major depressive episodes; a first episode is more likely to be immediately preceded by stressful life events than are recurrent ones. The relationship between stressful life events and social support has been a matter of some debate. Perhaps the lack of social support only increases the likelihood that life stress will lead to depression. More likely, however, the absence of social support constitutes a form of strain that provokes depression directly. There is evidence that neighborhood social disorder, for example, due to crime or illicit drugs, is a risk factor, and that a high neighborhood socioeconomic status, with better amenities, is a protective factor. Adverse workplace conditions, particularly demanding jobs with little scope for decision-making, are associated with depression, although diversity and confounding factors make it difficult to confirm the relationship is causal. There is mixed evidence regarding the role of social capital (features of social organization including interpersonal trust, civic engagement and cooperation for mutual benefit).

Risk Factors for depression
Certain risk factors have been identified that predispose people towards depression. Affective disorders, of which Unipolar depression is one type, have an approximate heritability of 60-70%, occuring more frequently in women. Men on the other hand tend to suffer Alcoholism more frequently, which can be indicative of underlying depression. Certain studies have suggested a genetic cause for depression, such as a faulty gene for the synthesis and/or transport of serotonin. Social approaches emphasize the role of traumatic Life Events in the depressed person's history.

Diagnosis, Co-morbidity, Treatment & Prognosis
Theoretical approaches to depression are many and varied, ranging from biological explanations, such as Monoamine oxidase theory - chemical imbalances of monoamine neurotransmitters such as serotonin, norepinephrine and dopamine - to theories based more on human needs not being met, such as Freud's Psychoanalytic theory and the humanistic theories of Maslow and Rogers. Recently, the cognitive model of human psychology has lead to treatments based on cognitive theories such as Cognitive Behavioural Therapy being employed.

Assessment of depression
The diagnosis and assessement of major depressive disorder is based on the patient's self-reported experiences, behavior reported by relatives or friends, and mental state. There is no laboratory test for major depression, although physicians generally request tests for physical conditions that may cause similar symptoms. The most common time of onset is between the ages of 30 and 40 years, with a later peak between 50 and 60 years. Major depression occurs about twice as frequently in women than men, although men are at higher risk for suicide. The accurate diagnosis of depression is an important issue. In the past evidence suggests the condition was often missed, particularly in the elderly and in children

Comorbidity in depression
Depression is associated with other clinical problems including eg Anxiety, Alcoholism, Substance abuse, Abuse, PTSD, Stress

Epidemiology of depression
The likelihood of suffering from depression is not the same for all of us. Epidemiologists study these different patterns of occurence.

Treatment
Most patients are treated in the community with antidepressant medication and supportive counselling, and some may undertake psychotherapy. Admission to hospital may be necessary in cases associated with self-neglect or a significant risk of harm to self or others. A minority with severe illness may be treated with electroconvulsive therapy (ECT), under a short-acting general anaesthetic. The course of the disorder varies widely, from a once-only occurrence lasting months to a lifelong disorder with recurrent major depressive episodes. Depressed individuals have a shorter life expectancy than those without depression, being more susceptible to medical conditions such as heart disease. Sufferers and former patients may be stigmatized.

There are a number of different psychological therapies that aim to treat depression.

The social context of depression
Depression occurs in different pattterns both within societies and between societies. There also cultural differences in how it is regarded and treated.

Depression in women
Women are suffer from depression far more frequently than men (HOW MUCH), approximately 1 in 3??? women will suffer from Depression at some point in their lives, compared to only 1 in 10??? men. Reasons for this include such causes as postnatal depression, hormonal influences due to mood instability at different stages in the menstrual cycle, and hormonal changes after menopause. Culturally it has been suggested that women suffer depression more frequently than men because they are more repressed and have less control over their lives than men. To counter this it has been suggested that men are unable to express their feelings as freely as women and instead suffer from conditions such as Alcoholism. There is possible co-morbidity with eating disorders in women and rarely with men.

Depression in men
As mentioned above, men suffer more frequently from alcoholism, which may be a sign of underlying depression. There is a significantly higher risk of suicide in young men compared to women of the same age. It seems that men are more likely to be successful in suicide atttempts than women, as there are fewer depressed men in any age group than women.

Depression in children
Depression is often misdiagnosed in children, and there is some controversy surrounding prescription of anti depressants to children. Certain anti-depressants are no longer recommended for prescription to children in the UK because of the potential risk of the drugs interfering with the development of the brain.

Depression in older adults
Depression strikes the elderly more frequently than it does the young. In part this is due to deterioration of the brain in elderly people, and can occur comorbidly with diseases such as alzheimers, parkinsons and following conditions such as stroke. It has also been suggested that a sedentiary lifestyle with little exercise can contribute to depression. Finally, aging people may become depressed after the death of a partner or loved one.

Depression in primary care
There is an increasing emphasis on the early diagnosis of clinical depression in primary care and on the management of the condition by primary care professionals

Depression and physical illness
Clinical depression is often found to accompany physical illness.