Depression (mood)
Depression is a mental state of low mood and aversion to activity. It affects about 3.5% of the global population, or about 280 million people worldwide, as of 2020. Depression affects a person's thoughts, behavior, feelings, and sense of well-being. The pleasure or joy that a person gets from certain experiences is reduced, and the afflicted person often experiences a loss of motivation or interest in those activities. People with depression may experience sadness, feelings of dejection or lack of hope, difficulty in thinking and concentration, hypersomnia or insomnia, overeating or anorexia, or suicidal thoughts.
Depression can have multiple, sometimes overlapping, origins. Depression can be a normal temporary reaction to life events, such as the loss of a loved one. Additionally, depression can be a symptom of some mood disorders, such as major depressive disorder, bipolar disorder, and dysthymia. Depression is also a symptom of some physical diseases and a side effect of some drugs and medical treatments.
Contributing factors
Life events
, such as bereavement, neglect, mental abuse, physical abuse, sexual abuse, or unequal parental treatment of siblings, can contribute to depression in adulthood. Childhood physical or sexual abuse in particular significantly correlates with the likelihood of experiencing depression over the survivor's lifetime. People who have experienced four or more adverse childhood experiences are 3.2 to 4.0 times more likely to suffer from depression. Poor housing quality, non-functionality, lack of green spaces, and exposure to noise and air pollution are linked to depressive moods, emphasizing the need for consideration in planning to prevent such outcomes. Locality has also been linked to depression and other negative moods. The rate of depression among those who reside in large urban areas is shown to be lower than those who do not. Likewise, those from smaller towns and rural areas tend to have higher rates of depression, anxiety, and psychological unwellness.Studies have consistently shown that physicians have had the highest depression and suicide rates compared to people in many other lines of work—for suicide, 40% higher for male physicians and 130% higher for female physicians.
Life events and changes that may cause depressed mood includes, but are not limited to, childbirth, menopause, financial difficulties, unemployment, stress, a medical diagnosis, bullying, loss of a loved one, natural disasters, social isolation, rape, relationship troubles, jealousy, separation, or catastrophic injury. Similar depressive symptoms are associated with survivor's guilt. Adolescents may be especially prone to experiencing a depressed mood following social rejection, peer pressure, or bullying.
Work and depression
A body of high-quality longitudinal research has linked adverse working to increased depressive symptoms and disorders. Workplace stressors that increase depression risk include excessive workloads, little autonomy, an unfavorable effort-reward imbalance, and workplace bullying.Childhood and adolescence
Depression in childhood and adolescence is similar to adult major depressive disorder, although young sufferers may exhibit increased irritability or behavioral dyscontrol instead of the more common sad, empty, or hopeless feelings seen with adults. Children who are under stress, experiencing loss, or have other underlying disorders are at a higher risk for depression. Childhood depression is often comorbid with mental disorders outside of other mood disorders; most commonly anxiety disorder and conduct disorder. Depression also tends to run in families.Personality
Depression is associated with low extraversion, and people who have high levels of neuroticism are more likely to experience depressive symptoms and are more likely to receive a diagnosis of a depressive disorder. Additionally, depression is associated with low conscientiousness. Some factors that may arise from low conscientiousness include disorganization and dissatisfaction with life. Individuals may be more exposed to stress and depression as a result of these factors.Side effect of medical treatment
It is possible that some early generation beta-blockers induce depression in some patients, though the evidence for this is weak and conflicting. There is strong evidence for a link between alpha interferon therapy and depression. One study found that a third of alpha interferon-treated patients had developed depression after three months of treatment. There is moderately strong evidence that finasteride when used in the treatment of alopecia increases depressive symptoms in some patients. Evidence linking isotretinoin, an acne treatment, to depression is strong. Other medicines that seem to increase the risk of depression include anticonvulsants, antimigraine drugs, antipsychotics, and hormonal agents such as gonadotropin-releasing hormone agonist.Substance-induced
Several drugs of abuse can cause or exacerbate depression, whether in intoxication, withdrawal, and from chronic use. These include alcohol, sedatives, opioids, stimulants, hallucinogens, and inhalants.Non-psychiatric illnesses
Depressed mood can be the result of a number of infectious diseases, nutritional deficiencies, neurological conditions, and physiological problems, including hypoandrogenism, Addison's disease, Cushing's syndrome, pernicious anemia, hypothyroidism, hyperparathyroidism, Lyme disease, multiple sclerosis, Parkinson's disease, celiac disease, chronic pain, stroke, diabetes, cancer, and HIV. Autistic burnout may also be misdiagnosed as depression.Studies have found that anywhere from 30 to 85 percent of patients suffering from chronic pain are also clinically depressed. A 2014 study by Hooley et al. concluded that chronic pain increased the chance of death by suicide by two to three times. In 2017, the British Medical Association found that 49% of UK chronic pain patients also had depression.
As many as 1/3 of stroke survivors will later develop post-stroke depression. Because strokes may cause damage to the parts of the brain involved in processing emotions, reward, and cognition, stroke may be considered a direct cause of depression.
Psychiatric syndromes
A number of psychiatric syndromes feature depressed mood as a main symptom. The mood disorders are a group of disorders considered to be primary disturbances of mood. These include major depressive disorder where a person has at least two weeks of depressed mood or a loss of interest or pleasure in nearly all activities; and dysthymia, a state of chronic depressed mood, the symptoms of which do not meet the severity of a major depressive episode. Another mood disorder, bipolar disorder, features one or more episodes of abnormally elevated mood, cognition, and energy levels, but may also involve one or more episodes of depression. Individuals with bipolar depression are often misdiagnosed with unipolar depression. When the course of depressive episodes follows a seasonal pattern, the disorder may be described as a seasonal affective disorder.Outside the mood disorders: borderline personality disorder often features an extremely intense depressive mood; adjustment disorder with depressed mood is 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; and posttraumatic stress disorder, a mental disorder that sometimes follows trauma, is commonly accompanied by depressed mood.
Inflammation
Historical legacy
Research suggests possible associations between Neanderthal genetics and some forms of depression.Authors and researchers have begun to conceptualize ways in which the historical legacies of racism and colonialism may create depressive conditions. Given the lived experiences of marginalized peoples, ranging from conditions of migration, class stratification, cultural genocide, labor exploitation, and social immobility, depression can be seen as a "rational response to global conditions", according to Ann Cvetkovich.
Psychogeographical depression overlaps somewhat with the theory of "deprejudice", a portmanteau of "depression" and "prejudice" proposed by Cox, Abramson, Devine, and Hollon in 2012, who argue for an integrative approach to studying the often comorbid experiences. Cox, Abramson, Devine, and Hollon are concerned with the ways in which social stereotypes are often internalized, creating negative self-stereotypes that then produce depressive symptoms.
Unlike the theory of "deprejudice", a psychogeographical theory of depression attempts to broaden study of the subject beyond an individual experience to one produced on a societal scale, seeing particular manifestations of depression as rooted in dispossession; historical legacies of genocide, slavery, and colonialism are productive of segregation, both material and psychic material deprivation, and concomitant circumstances of violence, systemic exclusion, and lack of access to legal protections. The demands of navigating these circumstances compromise the resources available to a population to seek comfort, health, stability, and sense of security. The historical memory of this trauma conditions the psychological health of future generations, making psychogeographical depression an intergenerational experience as well.
This work is supported by recent studies in genetic science which has demonstrated an epigenetic link between the trauma suffered by Holocaust survivors and genetic reverberations in subsequent generations.