Mood disorders and mental disorders are characterized by periods of depression, sometimes alternating with periods of elevated mood.
Although many people go through sad or elated moods from time to time, people who suffer from mood disorders suffer from severe mood states or for long periods, which violate their daily functioning. Between mood disorders are classified in the fourth edition (1994) Diagnostic and Statistical Manual of Mental Disorders (DSM - IV) are major depressive disorder and bipolar disorder and depression.
In the classification and diagnosis of mood disorders, doctors determine whether a mood unipolar or bipolar disorder.
When only one experienced extreme mood (state of depression), called this kind of unipolar depression. Major depression refers to a period of severe depression, characterized by negative or hopeless thoughts and physical symptoms such as fatigue. In major depressive disorder in some patients isolated bouts of depression. Between these episodes, the patient does not feel depression or other symptoms associated with depression. Other patients and recurrent episodes.
Bipolar depression or bipolar disorder (sometimes called manic depression) refers to the situation facing the people are parties to the mood. They alternate between depression ("low" mood) and mania or hypomania (the "high" mood). These patients go from depression to rise and unusually frantic mood. Mania and hypomania are similar, but mania is usually more severe and debilitating for the patient.
Depression is a recurrent or persistent depression that can last a lifetime. It is similar to major depressive disorder, but chronic depression and long-term, stable and light. Patients may have symptoms are not as severe as major depression, but symptoms for many years. It seems to be a mild form of depression is always there. In some cases, people can get a major depressive episode on top of depression, a condition sometimes called "double depression".