Section A - Affective disorders

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Part 1 - Major depression
Part 2 - Dysthymia
Part 3 - Bipolar affective disorder

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Affective disorders are disorders primarily characterized by a disturbance in mood, though other mental and somatic disturbances may be present. They affect individuals of all ages, with onset typically in adolescence or young adulthood.7 They are one of the most common and disabling mental illnesses worldwide.8 Individuals with a mood disorder typically experience impairments in social, occupational, educational, or other areas of functioning.1 Despite the long-term, sometimes lifetime, character of certain affective disorders, effective pharmaceutical treatment and management techniques are available for most of them that can help the individual lead a normal, productive life.

This section will highlight the three most common affective disorders: major depression, dysthymia, and bipolar affective disorder. Diagnosis for major depression and bipolar disorder is made given the occurrence of "episodes".7 Major depression is a disorder defined by episodes of persistent sadness and a loss of interest in activities. Dysthymia is similar in the sense that it is characterized by persistent feelings of sadness, but the feelings are chronic and less severe. These depressive disorders (major depression, dysthymia) are different from bipolar disorder in that (with these individuals) there has never been a manic, mixed, or hypomanic episode;7 in bipolar disorder, the mood alternates between episodes of persistent pathological sadness and episodes of extreme happiness and pleasure (mania).

Part 1 - Major depression

Major depression is a disorder characterized by one or more major depressive episodes, without a history of mania. A major depressive episode is diagnosed if an individual experiences either a depressed mood or a loss of interest or pleasure in most activities for a period of at least two consecutive weeks.7 The individual also experiences at least four additional symptoms that have changed since their previous level of functioning. These symptoms include changes in appetite or weight, sleep, and psychomotor activity; decreased energy; feelings of worthlessness or guilt; difficulty thinking, concentrating, or making decisions; or recurrent thoughts of death or suicidal behaviour.7 Furthermore, these symptoms are experienced for most of the day, nearly everyday.

Major depression, also known as unipolar major depression or major depressive disorder, is episodic in nature. For example, it can occur only once (as one single episode) or (most often) can be recurring. With recurrent major depression, repeated episodes can occur within periods of time (possibly many years) without symptoms, while others can have clusters of episodes that are very frequent. More than 50% of individuals who experience one major depressive episode suffer from a recurrent episode;1 in fact, the number of previous episodes is highly predictive of future episodes. An episode can last weeks, months, or even years.

Major depression can occur in all races and age groups, although onset is generally between ages 15 and 30 years. It occurs about twice as often in women than in men.1,9,10 Approximately 2%-6% of the general population will experience major depression in any 12-month period.1,9,10,11,12,13 Lifetime prevalence rates vary but have been reported between 2% and 19%,9,13,14, in Canadian adults over 18 years, specifically, lifetime prevalence rates are about 12%.1

No single cause of major depression has yet been identified, but there may be several contributing factors. During the last century, several theories of pathogenesis of depression were proposed. Monoamine theory is the most widespread and supported by clinical and laboratory findings as well as the effectiveness of contemporary antidepressants, acting as selective monoamines reuptake inhibitors.15 Genetic predisposition theory is supported with family history studies, showing that an individual with an immediate family member who has the disorder is 1.5-3 times more likely to experience major depression.7,16 The presence of other chronic or severe medical conditions (i.e., heart disease, cancer, diabetes) also increases the risk for experiencing major depression. Finally, a serious loss or any stressful life event, financial problems, or low self-esteem may also contribute to major depression. Though currently the monoamine theory is still the major one, the cumulative impact of genetics, adverse events in childhood and ongoing or recent stress is considered to be the best model of depression.15

Major depression is a treatable disorder. The most common treatments include antidepressant medications and psychotherapy/cognitive-behavioural therapy, but they are most effective when used in combination. Treatment is aimed at lessening the duration and intensity of the episodes of depression and preventing recurrence; maintenance treatment may be needed for individuals who experience recurring depression.

Depression is associated with increased death rates, as it is one of the most important risk factors for suicide: up to 15% of individuals with major depression will die by suicide.7,17,18 The Global Burden of Disease study, conducted by the World Health Organization and the World Bank, ranked (unipolar) major depression as third in 2004 in terms of the overall burden of all diseases in the world (measured by Disability-Adjusted Life Years),3 and predicts it will rise to second by the year 2030.8

Symptom severity is variable: the DSM-IV classifies major depression as mild, moderate, and severe, based on the number of symptoms and degree of impairment at diagnosis. We describe the implications each class of depression has on the health state of a depressed individual.

Major depression – Mild

ICD-9 code: 296.2 ICD-10 Depressive episode – Mild  F32.0/Recurrent depressive disorder, current episode mild F33.0

An individual has mild depression if few or no symptoms are present beyond those required for a diagnosis and only minor impairments in occupational or social functioning are experienced.7 This definition describes a patient with mild depression, and is also considered to describe a patient successfully treated for major depression.

Individuals with mild depression generally experience no limitations in physical functioning, but tend to lack the motivation to complete even the most common tasks. Emotionally, feelings of sadness and despair are constant; feelings of worthlessness and incompetence can be experienced. Periods of worry and fear are noted. Often sleep is disturbed, resulting in a loss of energy and fatigue. Concentration becomes difficult and distracted, and often the individual is indecisive. Social withdrawal is not uncommon.7,19

Classification (Major depression – Mild)

Major depression – Moderate

ICD-9 code: 296.2 ICD-10 Depressive episode – Mild  F32.1/ Recurrent depressive disorder, current episode moderate F33.1

An individual with moderate major depression experiences symptoms and/or functional impairments between those experienced in the mild and severe cases.7 A moderately depressed individual generally requires a great deal of effort to complete any given task, including a simple conversation. Often work and/or school obligations are neglected. Physical activity is reduced; sleep or appetite problems are common. Concentration and thinking are distracted. The potential for job loss and or loss of a social or familial role results in greater feelings of inadequacy, anxiety and hopelessness for the future.19

Classification ( Major depression – Moderate)

Major depression – Severe

ICD-9 code: 296.2 ICD-10 Depressive episode – Mild  F32.2-3 (with and without psychotic symptoms)/Recurrent depressive disorder, current episode severe F33.2-3(with and without psychotic symptoms)

Severe depression is categorized into two groups by the DSM-IV: severe depression without psychotic features, and severe depression with psychotic features.7 The latter case will not be discussed due to its relative rarity. To be diagnosed as severe, an individual must have several symptoms in addition to those required for a diagnosis and the symptoms result in substantial impairment in occupational or social functioning.7 This description refers to an individual with severe depression (and without psychotic features) who is either untreated or unsuccessfully treated.

There are significant implications on the health state of a severely depressed individual. Effort is lacking so much that severely depressed individuals may fail to maintain good personal hygiene because even this would be a burden. Excessive feelings of sadness and despair are experienced, and the risk of suicide increases as the severity of the depression increases. There are difficulties in remembering, concentrating and making decisions. Sex no longer becomes enjoyable; and there is almost complete withdrawal from interpersonal contact. Anxiety is experienced regularly. Physical symptoms, including abdominal pain, tension headaches, and musculoskeletal pain may arise.19

Classification (Major depression – Severe)

Part 2 - Dysthymia

Dysthymia is a mood disorder that is characterized by a chronic depressed mood that persists almost daily for at least two years, without a history of mania. During these periods of depressed mood, two or more additional symptoms are present, including poor appetite, overeating, insomnia, hypersomnia, low energy, fatigue, low self-esteem, poor concentration or difficulty making decisions, and/or feelings of hopelessness.7 Furthermore, these symptoms must cause clinically significant impairment in social, occupational, or other areas of functioning, and must not be due to another medical condition or from the physiological effects of a substance. Symptom-free periods can last no longer than two consecutive months. Dysthymia is also referred to as dysthymic disorder, neurotic depression, depressive neurosis, or chronic depression.20

Dysthymia can affect anyone, but is two to three times more likely in women than in men.1 Symptoms gradually persist over many years; onset is considered early if the dysthymia develops before age 21 and late if onset is at age 21 or after.7 Lifetime prevalence rates are between 3% and 6% in Canadian adults over age 18,1 and just under 3% in U.S. adults.14 The estimated one-year prevalence of dysthymia is between 0.8% and 3.1%.12,13

Causes of dysthymia are unknown, but hypotheses on the causes of major depression are parallel. For example, dysthymia is more common among first-degree biological relatives of people with major depression than among the general population.7 Treatment modalities are also similar: antidepressant medications and psycho- or cognitive therapy, often in combination. The disorder often persists for years, and therefore long-term continued treatment may be necessary, and may help to prevent recurrences. Although prognosis is good with treatment, often dysthymic individuals do not believe they are suffering from depression (rather they are just feeling "down") and consequently do not seek treatment.21

Dysthymia resembles major depression in its definition and associated features: the symptoms are similar but are chronic and relatively mild (and hence, not severe enough to meet the criteria for major depression).22 In addition, an individual with dysthymia is generally more functional than an individual with major depression, but is particularly impaired in social and interpersonal relationships.23 The implications of dysthymia on an individual's health state are described.


ICD-9 code: 300.4 ICD-10 – Dysthymia F34.1

Individuals suffering from dysthymia can generally function adequately but at less than peak performance. Difficulties with concentration and decision-making, decreased energy and anxious and irritable moods are experienced. Sleep disturbances are likely and cause at least mild levels of fatigue and decreased energy, which occasionally may be more severe. There are also limitations in social functioning due to social withdrawal and a loss of interest or pleasure in things they once enjoyed (e.g., sex), leading to difficulties with relationships. Persistent feelings of sadness, guilt, hopelessness, and inadequacy often make the sufferer believe it is part of their inherent personality, keeping them from feeling well and happy.21

Classification (Dysthymia)

Part 3 - Bipolar affective disorder

Bipolar disorder is a disorder characterized by one or more manic, depressive or mixed episodes. A manic episode is characterized by a period of at least one week during which there is an abnormally elevated, expansive, or irritable mood. There must also be the presence of at least three additional symptoms that include grandiosity (an exaggerated belief in one's importance); decreased need for sleep; pressured (intense) speech; flight of ideas (thoughts rapidly skip to distantly related ideas in no logical progression); distractibility; increased involvement in goal-directed activities; and involvement in pleasurable activities that have a high potential for painful consequences.7 This disturbance must be severe enough to cause impairments in social or occupational functioning, or to require hospitalization, and must not be due to another medical condition or from the physiological effects of a substance.7 A mixed episode, on the other hand, is characterized by a period of at least one week during which the criteria are met for both a manic episode and for a major depressive episode almost every day, and must also cause significant impairments in social or occupational functioning or require hospitalization.7 Almost all individuals with bipolar disorder experience one or more major depressive episodes as well. For this reason, bipolar disorder is also referred to as manic depression or manic depressive disorder. In general, an individual with bipolar disorder alternates moods from severe highs (mania) to severe lows (depression), often with periods of normal functioning in between. These mood changes can be rapid or gradual.24

Similar to major depression, bipolar disorder is episodic in nature, and almost always it is recurring; more than 90% of individuals who experience a manic episode will have future episodes.7 Furthermore, between 50% and 70% of manic episodes occur immediately before or immediately after a major depressive episode. The pattern of episodes are variable from person to person, however, they tend to be fairly predictable in the same individual. On average, individuals with bipolar disorder experience four episodes in a ten-year period.7

Bipolar disorder typically begins in late adolescence or early adulthood, with an average age of onset between 20 and 25 years.7 It can affect anyone of any race or ethnicity, and is equally common in men and women.1,9 Lifetime prevalence rates for bipolar disorder have been found to be between 0.2% and 1.7%.7,11,13 In Canadian adults in particular, studies have reported a lifetime prevalence of 2.4% and a 12-month prevalence of 1%.1

The exact cause of bipolar disorder is unknown. A serious life event (such as divorce), a financial problem, or an illness may trigger an episode in some individuals; it may be that some individuals are more prone to emotional or physical stressors. There may also be a chemical imbalance in the brain, which could contribute to the strong tendency for a genetic disposition: about 80% to 90% of individuals suffering from bipolar disorder have a relative with some form of depression.25 It may occur with no obvious trigger at all.

Although treatment of bipolar disorder may be complicated in certain cases, it is highly manageable. Medication often consists of mood stabilizers, such as Lithium, which is most effective against mania, and antidepressants for depressed episodes. Taking an antidepressant without an accompanying mood stabilizer has the potential to trigger a manic episode, therefore, these two medications are typically prescribed together. Psychological treatment is also available to help the individual detect their particular pattern of episodes, and also to develop strategies for managing the disorder. Due to the recurrent nature of bipolar disorder, treatment is generally long-term to prevent future episodes.

Left untreated, bipolar disorder can impose significant pressures emotionally, both on the sufferer and their families and coworkers. Still, only 27% of bipolar patients are in treatment;26 frequently individuals (in mania) do not recognize they are ill and need treatment because they feel well. We describe below the impact bipolar disorder has on an individual's health state while they are experiencing an acute, manic episode, and also while they are a patient undergoing active treatment. This information should be combined with the description of major depression for a full interpretation of the bipolar disorder process.

Bipolar affective disorder – Manic episode

ICD-9 code: 296.4 – 296.7 ICD-10 – F31

This description refers to an individual with bipolar affective disorder while in an acute, manic episode. Generally individuals in mania feel excessively happy and excited; euphoric. Although mania is not directly captured in the emotional state attribute below, euphoria causes severe limitations in other attributes. Typically, individuals with mania have inflated self-esteem, unwarranted optimism, and poor judgment, leading to participation in pleasurable activities that may have high potential for painful consequences, such as uncontrolled buying sprees, substance abuse, or unusual sexual behaviours (e.g., infidelity or promiscuity). Social relationships tend to be unstable; the individual is active, outgoing and likely feels they have a lot of friends, but behaves irrationally. Concentration typically becomes difficult and grandiose, and thinking becomes distracted and yet much faster than normal. Speech may become incoherent due to a flight of ideas – sentences are rarely finished because thoughts rapidly change – and because the individual tends to talk really fast. Anxiety and irritability are noted.

Classification (Bipolar affective disorder – Manic episode)

Bipolar affective disorder – Bipolar patient, active treatment

ICD-9 code: 296.4 – 296.7

This description refers to an individual who is being treated for bipolar affective disorder, which assumes the manic and depressive states to be mild (given the success rate for treatment) and chronic. Mania in its mild form is hard to distinguish from simply an optimistic mood; the individual is more lively and talkative than when in their depressed state. This, however, still imposes on an individual's quality of life. Behaviours that are constantly competing with each other can be hard to regulate; for example, when in mania, there is a decreased need for sleep and a heightened sex drive, when in depression, there is persistent fatigue and a diminished sex drive. Although the "polar" (meaning opposite) episodes are mild, they are still forcing the sufferer to deal with opposing demeanours, resulting in cognitive, social and physical limitations.

Classification (Bipolar affective disorder – Bipolar patient, active treatment)

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