Major depressive disorder (MDD), commonly called major depression, unipolar depression, or clinical depression, where a person has one or more major depressive episodes. After a single episode, Major Depressive Disorder (single episode) would be diagnosed. After more than one episode, the diagnosis becomes Major Depressive Disorder (Recurrent). Depression without periods of mania is sometimes referred to as unipolar depression because the mood remains at one emotional state or “pole”.
Individuals with a major depressive episode or major depressive disorder are at increased risk for suicide. Seeking help and treatment from a health professional dramatically reduces the individual’s risk for suicide. Studies have demonstrated that asking if a depressed friend or family member has thought of committing suicide is an effective way of identifying those at risk, and it does not “plant” the idea or increase an individual’s risk for suicide in any way. Epidemiological studies carried out in Europe suggest that at this moment, roughly 8.5 percent of the worlds population are suffering from a depressive disorder. No age group seems to be exempt from depression and studies have found that depression appears in infants as young as 6 months old who have been separated from their mothers.
Diagnosticians recognize several subtypes or course specifiers:
Atypical depression (AD) is characterized by mood reactivity (paradoxical anhedonia) and positivity, significant weight gain or increased appetite (“comfort eating”), excessive sleep or somnolence (hypersomnia), a sensation of heaviness in limbs known as leaden paralysis, and significant social impairment as a consequence of hypersensitivity to perceived interpersonal rejection. Difficulties in measuring this subtype have led to questions of its validity and prevalence.
Melancholic depression is characterized by a loss of pleasure (anhedonia) 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.
Psychotic major depression (PMD), or simply psychotic depression, is the term for a major depressive episode, particularly of melancholic nature, where the patient experiences psychotic symptoms such as delusions or, less commonly, hallucinations. These are most commonly mood-congruent (content coincident with depressive themes).
Catatonic depressionis 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 immobile or exhibits purposeless or even bizarre movements. Catatonic symptoms can also occur in schizophrenia, a manic episode, or be due to neuroleptic malignant syndrome.
Postpartum depression (PPD) is listed as a course specifier in DSM-IV-TR; it refers to the intense, sustained and sometimes disabling depression experienced by women after giving birth. Postpartum depression, which has incidence rate of 10–15%, typically sets in within three months of labor, and lasts as long as three months. It is quite common for women to experience a short term feeling of tiredness and sadness in the first few weeks after giving birth; however, postpartum depression is different because it can cause significant hardship and impaired functioning at home, work, or school as well as possibly difficulty in relationships with family members, spouses, friends, or even problems bonding with the newborn …
Seasonal affective disorder (SAD), also known as “winter depression” or “winter blues”, is a specifier. Some people have a seasonal pattern, with depressive episodes coming on in the autumn or winter, and resolving 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. It is commonly hypothesised that people who live at higher latitudes tend to have less sunlight exposure in the winter and therefore experience higher rates of SAD, but the epidemiological support for this proposition is not strong (and latitude is not the only determinant of the amount of sunlight reaching the eyes in winter). SAD is also more prevalent in people who are younger and typically affects more females than males.
Dysthymia, which is a chronic, different mood disturbance where 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). The treatment of dysthymia is largely the same as for major depression, including antidepressant medications and psychotherapy.
Depressive Disorder Not Otherwise Specified (DD-NOS) is designated by the code 311 for depressive disorders that are impairing but do not fit any of the officially specified diagnoses. According to the DSM-IV, DD-NOS encompasses “any depressive disorder that does not meet the criteria for a specific disorder.” It includes the research diagnoses of recurrent brief depression, and minor depressive disorderlisted below.
Recurrent brief depression (RBD), distinguished from major depressive disorder primarily by differences in duration. People with RBD have depressive episodes about once per month, with individual episodes lasting less than two weeks and typically less than 2–3 days. Diagnosis of RBD requires that the episodes occur over the span of at least one year and, in female patients, independently of the menstrual cycle. People with clinical depression can develop RBD, and vice versa, and both illnesses have similar risks.