At the diagnostic level, mood disorders are based on the concept of episode. The DSM-IV describes three types of affective episodes (depressive, manic and hypomanic), with the disorders being defined in terms of the duration of these episodes and the combination of episodes observed (Vázquez & Sanz, 1995).
major depressive episode
Major depressive episode is characterized by depressed mood or a loss of interest or pleasure in almost all activities for at least 2 weeks and most of the day. In children and adolescents the mood may be irritable rather than sad. In addition, the subject must experience at least four other symptoms that include changes in appetite or weight, sleep, and psychomotor activity; lack of energy; feelings of undervaluation or guilt; difficulty thinking, concentrating, or making decisions, and recurrent thoughts of death or suicidal ideation, plans, or attempts. The episode must be accompanied by significant clinical discomfort or deterioration in social, occupational, or other important areas of the individual’s activity. In some subjects with mild episodes, activity may seem normal, but at the cost of a very significant effort.
The appearance of symptoms
Symptoms of a major depressive episode usually develop over days or weeks, sometimes preceded by weeks or months of anxiety symptoms and mild depressive symptoms. The duration of a major depressive episode is also variable; it is common for an untreated episode to last 6 months or more, regardless of the age of onset. In most cases there is a complete remission of symptoms and you can return to normal functioning.
Between 20 and 30% of major depressive episodes partially remit, some depressive symptoms persist for months or even years, although not with such intensity and disabling. These people are more likely to suffer new depressive episodes.
Between 5-10%, the major depressive episode becomes chronic and can last 2 or more years.
Studies indicate that depressive episodes appear twice as frequently in women as in men. A significant proportion of women report a worsening of the symptoms of the major depressive episode a few days before the start of menstruation.
manic episode
A manic episode is defined by a specific period during which the mood is abnormally and persistently elevated, expansive, or irritable. This period of abnormal mood should last at least 1 week (or less if hospitalization is required). The mood disturbance must be accompanied by at least three other symptoms from a list that includes increased self-esteem or grandiosity, decreased need for sleep, verbose speech, flight of ideas, distractibility, increased purposeful activities, or agitation. psychomotor and excessive involvement in pleasurable activities with a high potential to produce serious consequences.
The appearance of symptoms
The average age of onset of a first manic episode is in the early years of the third decade of life, but there are some cases of onset in adolescence and others that begin after the age of 50. Manic episodes begin abruptly, with a rapid increase in symptoms within a few days. Manic episodes frequently appear after psychosocial stress. Episodes usually last from a few weeks to several months and are shorter and more abruptly ending than major depressive episodes. In many cases (50-60%) a major depressive episode immediately precedes or follows a manic episode, without an intervening period of euthymia. If the manic episode occurs in the postpartum period, there may be an increased risk of recurrences in other postpartum periods and the postpartum onset specification should be applied.
Mixed episode
A mixed episode is characterized by a period of time (at least 1 week long) in which the criteria for both a manic episode and a major depressive episode are met almost every day. The subject experiences rapidly alternating mood states (sadness, irritability, euphoria), accompanied by symptoms of a manic episode and a major depressive episode. Presenting symptoms typically include agitation, insomnia, altered appetite, psychotic symptoms, and suicidal ideation. The disturbance must be severe enough to cause significant social or occupational impairment or to require hospitalization, or is characterized by the presence of psychotic symptoms. The disturbance is not due to the direct physiological effects of a substance (e.g., a drug, medication, or other treatment) or a medical illness (e.g., hyperthyroidism).
The appearance of symptoms
Mixed episodes may arise from a manic episode or a de novo or major depressive episode. For example, in a subject with 3 weeks of manic symptoms followed by 1 week of both manic and depressive symptoms, the diagnosis should be changed from bipolar I disorder, most recent manic episode, to bipolar I disorder, most recent mixed episode. Mixed episodes can last from weeks to several months and may subside to a period with few or no symptoms or progress to a major depressive episode. It is much less common for a mixed episode to evolve into a manic episode.
Hypomanic episode
A hypomanic episode is defined as a defined period during which there is an abnormal and persistently elevated, expansive, or irritable mood lasting at least 4 days. This period of abnormal mood must be accompanied by at least three other symptoms from a list that includes increased self-esteem or grandiosity (not delusional), decreased need for sleep, verbose language, flight of ideas, distractibility, increased intentional activities or psychomotor agitation and excessive involvement in pleasurable activities with a high potential to produce serious consequences. If the mood is irritable (rather than elevated or expansive), there should be at least four of the above symptoms. The list of additional symptoms is identical to that defining a manic episode except that delusions and hallucinations cannot be present.
The appearance of symptoms
In general, hypomanic episodes begin abruptly, with a rapid increase in symptoms over 1 or 2 days. Episodes usually last from a few weeks to several months and are shorter and more abruptly ending than major depressive episodes. In many cases the hypomanic episode can be preceded or followed by a major depressive episode. Available studies suggest that 5-15% of subjects with hypomania will eventually have a manic episode.