Clinical depression

Clinical depression

Clinical depression (also called major depressive disorder, or unipolar depression when compared to bipolar disorder) is a common mood disorder in psychology and psychiatry, in which a person's enjoyment of life and ability to function socially and in day to day matters is disrupted by intense sadness, melancholia, numbness, or despair.

Clinical depression differs from the common term depression and the everyday expression of "feeling depressed". It is diagnosed medically, and treated by therapy and possibly antidepressant drugs. There are several subtypes, some of which meet the popular perception of sadness, agitation and disruption of sleeping and eating, and others of which do not disrupt enjoyment of good things but create a highly disruptive cycle of inner paralysis and lethargy.

Clinical depression affects about 7–18% of the population on at least one occasion in their lives, before the age of 40.

General background

Although a low mood or state of dejection that does not affect functioning is often colloquially referred to as depression, clinical depression is a clinical diagnosis and may be different from the everyday meaning of "being depressed." Many people identify the feeling of being clinically depressed as "feeling sad for no reason", or "having no motivation to do anything." A person suffering from depression may feel tired, sad, irritable, lazy, unmotivated, and apathetic. Clinical depression is generally acknowledged to be more serious than normal depressed feelings. It often leads to constant negative thinking and sometimes substance abuse or self-harm. Extreme depression can culminate in its sufferers attempting or completing suicide.

Without careful assessment, delirium can easily be confused with depression and a number of other psychiatric disorders because many of the signs and symptoms are conditions present in depression, as well as other mental illnesses including dementia and psychosis.

History

The modern idea of depression appears similar to the much older concept of melancholia. The name melancholia derives from "black bile," one of the "four humours" postulated by Galen.

Clinical depression was originally considered to be a chemical imbalance in transmitters in the brain, a theory based on observations made in the 1950s of the effects of reserpine and isoniazid in altering monoamine neurotransmitter levels and affecting depressive symptoms. Since these suggestions, many other causes for clinical depression have been proposed.

Prevalence

Clinical depression affects about 7–18% of the population on at least one occasion in their lives, before the age of 40. In some countries, such as Australia, one in four women and one in six men will suffer from depression. In Canada, major depression affects approximately 1.35 million people. Because people who have one episode of depression may have more in the future, the first time a young person becomes depressed is important both as a personal and public health concern.

About twice as many females as males report or receive treatment for clinical depression, though this imbalance is shrinking over the course of recent history; this difference seems to completely disappear after the age of 50–55. Clinical depression is currently the leading cause of disability in North America as well as other countries, and is expected to become the second leading cause of disability worldwide (after heart disease) by the year 2020, according to the World Health Organization.

Recent studies suggest that the diagnostic criteria for depression are far too broad, resulting in diagnosis of clinical depression in people who are not truly clinically depressed and who have shown normal responses to negative events.

Types

The diagnostic category major depressive disorder appears in the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association. The term is generally not used in countries which instead use the ICD-10 system, but the diagnosis of depressive episode is very similar to an episode of major depression. Clinical depression also usually refers to acute or chronic depression severe enough to need treatment. Minor depression is a less-used term for a subclinical depression that does not meet criteria for major depression but where there are at least two symptoms present for two weeks.

Major clinical depression

Major Depression, or, more properly, Major Depressive Disorder (MDD), is characterized by a severely depressed mood that persists for at least two weeks. Major Depressive Disorder is specified as either "a single episode" or "recurrent", depending on whether periods of depression occur as discrete events or recur within an individual's lifespan. Episodes of major or clinical depression may be further divided into mild, major or severe. If the patient has already had an episode of mania or markedly elevated mood, a diagnosis of bipolar disorder (also called bipolar affective disorder) is usually made instead of MDD; depression without periods of elation or mania is therefore sometimes referred to as unipolar depression because the mood remains at one emotional state ("pole"). The diagnosis also usually excludes cases where the symptoms are a normal result of bereavement. Diagnosticians recognize several possible subtypes of Major Depressive Disorder. ICD-10 does not specify a melancholic subtype, but does distinguish by presence or absence of psychosis.

* Depression with Melancholic Features – Melancholia 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, anorexia (excessive weight loss, not to be confused with Anorexia Nervosa), or excessive guilt.

* Depression with Atypical Features – Atypical depression is characterized by mood reactivity (paradoxical anhedonia) and positivity, significant weight gain or increased appetite ("comfort eating"), excessive sleep or somnolence (hypersomnia), leaden paralysis, or significant social impairment as a consequence of hypersensitivity to perceived interpersonal rejection. Contrary to its name, atypical depression is the most common form of depression.

* Depression with Psychotic Features – Some people with major depressive or manic episodes may experience psychotic features. They may be presented with hallucinations or delusions that are either mood-congruent (content coincident with depressive themes) or non-mood-congruent (content not coincident with depressive themes). It is clinically more common to encounter a delusional system as an adjunct to depression than to encounter hallucinations, whether visual or auditory.

Other categories of depression

* Dysthymia is a long-term, mild depression that is diagnosed when there has been a persistently depressed mood for at least two years. By definition, the symptoms are not as severe as those for Major Depression, although people with Dysthymia are vulnerable to co-occurring episodes of Major Depression (sometimes referred to as "Double Depression"). This disorder often begins in adolescence and crosses the lifespan. Dysthymic disorder typically develops first and may be followed later by one or more Major Depressive Episodes.

* Bipolar I Disorder is an episodic illness characterized by episodes of Mania, often accompanied by periods of Major Depression. In the United States, Bipolar Disorder was previously called "Manic Depression", though this term is no longer favored by the medical community.

* Bipolar II Disorder is an episodic illness that is defined primarily by Major Depression accompanied by at least one episode of hypomania.

* Postpartum Depression or Post-Natal Depression is clinical depression that occurs within four weeks of childbirth. Owing to physical, mental and emotional exhaustion combined with sleep-deprivation, it has been suggested that motherhood may predispose some women to become depressed.

* Premenstrual dysphoric disorder is a pattern of recurrent depressive symptoms tied to the menstrual cycle. The premenstrual decline in brain serotonin function is strongly correlated with the concomitant worsening of self-rated cardinal mood symptoms. Of considerable clinical importance, the recent understanding of premenstrual dysphoria as depression points directly to effective treatment with Selective serotonin reuptake inhibitor (SSRI) antidepressants. Previously, disrupting ovarian cyclicity had been the only recognized treatment. A recent review of studies of a number of SSRIs has revealed that they can effectively ameliorate symptoms of premenstrual dysphoria and may actually work best when taken only during the part of the menstrual cycle when dysphoric symptoms are evident.

* Recurrent Brief Depressive Disorder or Recurrent Brief Depression is in the ICD-10 classification. Diagnostic criteria distinguish between mild, moderate and severe depressive episodes. Depressive episodes occur about once per month over the past year, with individual episodes lasting less than two weeks (typically less than 2-3 days); episodes do not occur solely in relation to the menstrual cycle. Some people are at risk of self-harm, as well as the disruption to everyday life, particularly work.

Overlapping psychological features

- Anxiety

The different types of depression and anxiety are classified separately by the DSM-IV-TR, with the exception of hypomania, which is included in the bipolar disorder category. Despite the different categories, depression and anxiety can indeed be co-occurring (occurring together), independently (without mood congruence), or comorbid (occurring together, with overlapping symptoms, and with mood congruence). In an effort to bridge the gap between the DSM-IV-TR categories and what clinicians actually encounter, experts such as Herman Van Praag of Maastricht University have proposed ideas such as anxiety/aggression-driven depression. This idea refers to an anxiety/depression spectrum for these two disorders, which differs from the mainstream perspective of discrete diagnostic categories.

Although there is no specific diagnostic category for the comorbidity of depression and anxiety in the DSM or ICD, the National Comorbidity Survey (US) reports that 58 percent of those with major depression also suffer from lifetime anxiety. Supporting this finding, two widely accepted clinical colloquialisms include

* agitated depression - a state of depression that presents as anxiety and includes akathisia (heightened restlessness), suicide, insomnia (not early morning wakefulness), nonclinical (meaning "doesn't meet the standard for formal diagnosis") and nonspecific panic, and a general sense of dread.

* akathitic depression - a state of depression that presents as anxiety or suicidality and includes akathisia but does not include symptoms of panic. Some consider it a form of mixed state.

It is also clear that even mild anxiety symptoms can have a major impact on the course of a depressive illness, and the commingling of any anxiety symptoms with the primary depression is important to consider. A pilot study by Ellen Frank et al., at the University of Pittsburgh, found that depressed or bipolar patients with lifetime panic symptoms experienced significant delays in their remission.[citation needed] These patients also had higher levels of residual impairment, or the ability to get back into the swing of things. On a similar note, Robert Sapolsky of Stanford University and others also argue that the relationship between stress, anxiety, and depression could be measured and demonstrated biologically. To that point, a study by Heim and Nemeroff et al., of Emory University, found that depressed and anxious women with a history of childhood abuse recorded higher heart rates and the stress hormone ACTH when subjected to stressful situations.

- Hypomania

Hypomania, as the name suggests, is a state of mind or behavior that is "below" (hypo) mania. In other words, a person in a hypomanic state often displays behavior that has all the hallmarks of a full-blown mania (e.g., marked elevation of mood that is characterized by euphoria, overactivity, disinhibition, impulsivity, a decreased need for sleep, hypersexuality), but these symptoms, though disruptive and seemingly out of character, are not so pronounced as to be considered a diagnosably manic episode. In a psychiatric context, it is important to identify the possible presence and characteristics of manic and hypomanic episodes, since these may lead to a diagnosis of bipolar disorder, which is medically treated differently from depression.

Another important point is that hypomania is a diagnostic category that includes both anxiety and depression. It often presents as a state of anxiety that occurs in the context of a clinical depression. Patients in a hypomanic state often describe a sense of extreme generalized or specific anxiety, recurring panic attacks, night terrors, guilt, and agency (as it pertains to codependence and counterdependence). All of this happens while they are in a state of retarded or somnolent depression. This is the type of depression in which a person is lethargic and unable to move through life. The terms retarded and somnolent are shorthand for states of depression that include lethargy, hypersomnia, a lack of motivation, a collapse of ADLs (activities of daily living), and social withdrawal. This is similar to the shorthand used to describe an "agitated" or "akathitic" depression.

In considering the hypomania-depression connection, a distinction should be made between anxiety, panic, and stress. Anxiety is a physiological state that is caused by the sympathetic nervous system. Anxiety does not need an outside influence to occur. Panic is related to the "fight or flight" mechanism. It is a reaction, induced by an outside stimulus, and is a product of the sympathetic nervous system and the cerebral cortex. More plainly, panic is an anxiety state that we are thinking about. Finally, stress is a psychosocial reaction, influenced by how a person filters nonthreatening external events. This filtering is based on one's own ideas, assumptions, and expectations. Taken together, these ideas, assumptions, and expectations are called social constructionis.