Overview of depression

Related Diseases & Conditions

• Depression in adults

  Summary

  Depressive disorders are characterized by persistent low mood, loss of interest and enjoyment, neurovegetative symptoms, and reduced energy, causing varying levels of social and occupational dysfunction. Depressive disorders are very common and are among the leading causes of disability worldwide.[2]​ The etiology of depression remains poorly understood. Integrative models, taking into account biologic and social variables, most effectively reflect the complex etiology. Depressive symptoms include depressed mood, anhedonia, weight changes, libido changes, sleep disturbance, psychomotor problems, low energy, excessive guilt, poor concentration, and suicidal ideation. In some cases the mood is not sad, but anxious or irritable or flat.[1]​ Key risk factors include older age; recent childbirth, stress, or trauma; coexisting medical conditions (diabetes mellitus, cancer, stroke, myocardial infarction, and obesity); personal or family history of depression; certain medications (e.g., corticosteroids) and female sex.
• Depression in children

  Summary

  Characterized by sad or irritable mood, anhedonia, decreased capacity to have fun, decreased self-esteem, sleep disturbance, social withdrawal or impaired social relationships, and impaired school performance. The presence of poverty has been associated with an increased risk of children requiring treatment for depression.[3] Childhood depression is likely to be caused by both genetic and environmental factors, and by their interactions. Life stress has been strongly associated with risk of depression, especially in girls.​​[4]​ Adolescent and preadolescent depressive disorders are clinical diagnoses, based on a comprehensive diagnostic evaluation of history and presenting symptoms. Key risk factors include positive family history of depression, other parental psychopathology, history of stressful life events or trauma, female sex, postpartum status, comorbid psychiatric disorders or chronic medical illnesses, and neighbourhood and social instability are important risk factors for depression.
• Disruptive mood dysregulation disorder

  Summary

  Disruptive mood dysregulation disorder is a category of depressive disorders first diagnosed at 6-18 years of age, with age of onset before 10 years. It is characterized by the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, text revision (DSM-5-TR) as severe and recurrent temper outbursts on average 3 or more times per week for at least 1 year, and a persistent irritable or angry mood for most of the day nearly every day between temper outburst.[1]
• Persistent depressive disorder

  Summary

  Includes common forms of depression, but lasting longer than acute major depressive disorder. The DSM-5-TR modified its classification system to include all chronic forms of depression under the single category persistent depressive disorder, which includes both chronic major depressive disorder and the previous category of dysthymic disorder (dysthymia), or chronic low-grade depression. Chronic major depressive disorder may be more common than dysthymia. The etiology of the various subtypes of persistent depressive disorder, as well as other mood disorders, is unknown. It is likely that depressive disorders are heterogeneous in nature, and this may be particularly true for persistent depressive disorder, which has a wide range of presentations and varying severity.[5]​ The DSM-5-TR includes specifiers to identify different pathways to the diagnosis of persistent depressive disorder and various presentations based on severity and clinical characteristics.[1]
• Postpartum depression

  Summary

  Postpartum depression refers to the development of a depressive illness following childbirth and may form part of a bipolar or, more usually, a unipolar illness. Postpartum depression is not recognized by current classification systems as a condition in its own right, but the onset of a depressive episode within 4 weeks of childbirth can be recorded via the peripartum-onset specifier in the DSM-5-TR.[1] In common usage, depressive episodes occurring within 6-12 months of delivery may be considered to be postpartum depression. One large review of 143 studies from 40 countries reports a wide range in the prevalence of postpartum depression worldwide, ranging from 0% to 60%.[6]​ The etiology is poorly understood and clinical consensus is lacking; the development of postpartum depression is likely to involve an interaction between psychologic social, and biologic factors.[7]

  Characteristics of postpartum depression may include guilt about the depressive symptoms, ambivalent feelings toward the infant, impaired bonding, and obsessive ruminations, including intrusive thoughts about harming the infant. Postpartum depression should be distinguished from a minor mood disturbance (postpartum blues or "baby blues"), in which the symptoms generally resolve within 2 weeks.
• Premenstrual syndrome and dysphoric disorder

  Summary

  Premenstrual syndrome (PMS) is characterized by cyclical, physical, and behavioral symptoms occurring in the luteal phase of the normal menstrual cycle (the period between ovulation and onset of menstruation). Premenstrual dysphoric disorder (PMDD) is a more severe variant that includes at least one affective symptom. Depression may coexist with PMS or PMDD in up to 50% of cases. A diagnosis of PMS or PMDD may predate a diagnosis of depression.[8]​ PMS and PMDD are diagnoses of exclusion, confirmed by a prospective symptom diary that verifies their repetitive, cyclical nature. Physical exam and limited laboratory testing are typically normal. Key risk factors include postpubescent and premenopausal women, family history, and mood disorders.
• Seasonal affective disorder

  Summary

  Seasonal affective disorder (SAD) is a subtype of major depression and bipolar disorder, occurring with seasonal change over at least a 2-year period. Atypical vegetative symptoms of depression are common, such as hypersomnia, hyperphagia, and weight gain. Most commonly presents with onset of depression in the autumn or winter, and full remission of symptoms over the spring or summer. Diminished light during winter months and increased light during summer months may contribute to risk for seasonal mood variations.[9]​ Lifetime estimates for depressive and bipolar disorders with a seasonal pattern average between 0.4% and 2.9% in US, Canadian, and UK community studies.[10] [11] [12]​​ Some estimates may be as high 9.7%.[13] However, these differences are probably due to differences in the sampling and diagnostic criteria used. Assessment is based on self-report, clinical interview, and behavioral observation. Risk factors that are strongly associated with SAD include being a woman, an age of onset of 20-30 years, having a positive family history of the condition, and living in an area exposed to diminished light during winter and increased light during summer.
• Bipolar disorder in adults

  Summary

  A recurrent and often chronic mental illness, bipolar disorder is marked by episodes of hypomania or mania and depression, associated with a change or impairment in functioning. The long-term course of illness is characterized by a predominance of depression, although a history of at least one manic, hypomanic, or mixed episode is required to make the diagnosis of a bipolar disorder.

  Bipolar I disorder: at least one manic episode.

  Bipolar II disorder: has never had a full manic episode; at least one hypomanic episode and at least one major depressive episode.[1]

  Global prevalence of bipolar disorder is estimated to be approximately 2.5%.[14]​ The exact cause of bipolar disorder is unknown; in common with many psychiatric disorders, it is considered to be caused by the complex interaction of multiple genetic, cellular, and environmental factors.[15]​ Key risk factors include early age of mood disorder onset, family history of bipolar disorder or suicide, poor or limited response to traditional antidepressants, highly recurrent mood episodes, comorbid anxiety or substance misuse disorders, and a pattern of psychosocial instability.
• Bipolar disorder in children

  Summary

  Bipolar disorder is an uncommon condition in children that becomes more frequent in teens, approaching the rate of frequency seen in adults.[16] [17] The adult criteria describe a disorder of fluctuating mood cycles, consisting of episodes of elevated mood and increased activity or energy (mania) lasting at least 1 week, and episodes of lowered mood and activity (depression); an episode of mania is necessary for a diagnosis to be made. The diagnosis can be controversial, as criteria overlap with other childhood conditions such as ADHD and comorbid oppositional defiant disorder.
• Suicide risk management

  Summary

  Suicide risk mitigation refers to the identification, assessment, intervention, and treatment of a person at risk of suicide. It is an ongoing process whether due to a mental illness or a life crisis. Suicide is an important cause of death globally and a significant public health concern. An estimated 800,000 people die by suicide each year; it is the second leading cause of death among people aged 15-29 years.[18] Suicide is associated with a constellation of psychologic, biologic, genetic, social, and environmental factors, but whether these factors are causative remains uncertain. Self-harm and suicidal thoughts should be taken seriously, and met with empathy, compassion, and understanding given that they are risk factors for suicide, particularly when associated with a history of a mental illness (most commonly major depressive disorder and substance misuse).