Mood disorders are among the most common diagnoses in psychiatry. Mood is a persistent emotional state (as differentiated from affect, which is the external display of feelings). There are three major categories of mood disorders according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition: unipolar mood disorders (major depressive disorder, dysthymic disorder), bipolar mood disorders (bipolar I disorder, bipolar II disorder, and cyclothymic disorder), and mood disorders having a known etiology (substance-induced mood disorder and mood disorder due to a general medical condition) (Table 2-1).
- Unipolar disorders
- Substance-induced mood disorder
- Mood disorder due to general medical condition
The best available evidence suggests that mood disorders lie on a continuum with normal mood. Although mania and depression are often viewed as opposite ends of the mood spectrum, they can occur simultaneously in a single individual within a brief period, giving rise to the concept of mixed mood states.
Mood disorders are characterized by a disturbance in the regulation of mood, behavior, and affect. Mood disorders are subdivided into (1) depressive disorders, (2) bipolar disorders, and (3) depression in association with medical illness or alcohol and substance abuse. Depressive disorders are differentiated from bipolar disorders by the absence of a manic or hypomanic episode. The relationship between pure depressive syndromes and bipolar disorders is not well understood; depression is more frequent in families of bipolar individuals, but the reverse is not true. In the Global Burden of Disease Study conducted by the World Health Organization, unipolar major depression ranked fourth among all diseases in terms of disability-adjusted life years and was projected to rank second by year 2020. In the United States, lost productivity directly related to depression has been estimated at $44 billion per year.
Mood disorders affect about 10% of the population. Everyone experiences "highs" and "lows" in life, but people with mood disorders experience them with greater intensity and for longer periods of time than most people.
Depression is the most common mood disorder; a person with depression feels "very low." Symptoms may include: feelings of hopelessness, changes in eating patterns, disturbed sleep, constant tiredness, an inability to have fun, and thoughts of death or suicide.
People with bipolar disorder have periods of depression and periods of feeling unusually "high" or elated. The "highs" get out of hand, and the manic person can behave in a reckless manner, sometimes to the point of financial ruin or getting in trouble with the law.
A common and serious mental disorder characterized by loss of contact with reality (psychosis), hallucinations (false perceptions), delusions (false beliefs), abnormal thinking
Major depressive disorder is diagnosed after a single episode of major depression (Table 2-2). It is characterized by emotional changes, primarily depressed mood, and by so-called vegetative changes, consisting of alterations in sleep, appetite, and energy levels.
The lifetime prevalence (will occur at some point in a person's life) rate for major depressive disorder is 5% to 20%. The female-male ratio is 2: 1. Race distributions appear equal, and socioeconomic variables do not seem to be a factor. The incidence (rate of new cases) is greatest between the ages of 20 and 40 and decreases after the age of 65.
Psychological theories of depression generally view interpersonal losses (actual or perceived) as risk factors for developing depression. In fact, available evidence suggests that childhood loss of a parent or loss of a spouse are associated with depression.
Prevelance statistics for Mood disorders:
The following statistics relate to the prevalence of Mood disorders:
4.5% of population self-reported having mood disorders in Australia 2001 (ABS 2001 National Health Survey, Australia's Health 2004, AIHW)
3.4% of male population self-reported having mood disorders in Australia 2001 (ABS 2001 National Health Survey, Australia's Health 2004, AIHW)
5.5% of female population self-reported having mood disorders in Australia 2001 (ABS 2001 National Health Survey, Australia's Health 2004, AIHW)
849,000 people self-reported having mood disorders in Australia 2001 (ABS 2001 National Health Survey, Australia's Health 2004, AIHW)
529,000 women self-reported having mood disorders in Australia 2001 (ABS 2001 National Health Survey, Australia's Health 2004, AIHW)
320,000 men self-reported having mood disorders in Australia 2001 (ABS 2001 National Health Survey, Australia's Health 2004, AIHW)
Mood disorders, or affective disorders, are mental health problems such as depression, bipolar disorder, and mania. Mood disorders can occur in anyone, including children. The cause of mood disorders is not fully understood, but an imbalance in brain chemicals known as neurotransmitters is likely to play a role. Sometimes mood disorders may be related to a medical condition, substance abuse, life events, or other causes.
The most common types of mood disorders include major depression, dysthymic disorder (milder depressive disorder), and bipolar disorder, in which alternating episodes of depression and mania (elevated mood) occur in the same individual. It is normal for your mood to change, and most people go through times of feeling sad. When these feelings last for a very long time or interfere with your life, however, you may have a mood disorder.
Symptoms of mood disorders include feelings of sadness, hopelessness, helplessness or inadequacy that do not go away; guilt; suicidal thoughts; fatigue; changes in appetite; irritability; difficulty concentrating; and trouble engaging in daily tasks and relationships. Mood disorders can also cause an elevated mood (mania) that is accompanied by feelings of grandiosity, extreme energy, and heightened arousal. These feelings are stronger and last longer than normal, and interfere with day-to-day life.
Treatment for mood disorders depends on the evaluation of a medical professional. Medication, cognitive therapy, behavioral therapy, and lifestyle modification may all be used. It is important to get early treatment for a mood disorder to reduce the severity of symptoms and manage any complications.
Bipolar I disorder is the most serious of the bipolar disorders and is diagnosed after at least one episode of mania (Table 2-3). Patients with bipolar I disorder typically also have major depressive episodes in the course of their lives.
The lifetime prevalence is 0.4% to 1.6% and the male-female ratio is equal. There are no racial variations in incidence.
Genetic and familial studies reveal that bipolar I disorder is associated with increased bipolar I, bipolar II, and major depressive disorders in first-degree relatives. X linkage has been demonstrated in some studies but remains controversial. Mania can be precipitated by psychosocial stressors, and there is evidence that sleep/wake cycle perturbations may predispose a person to mania.