Clinical depression is more than just feeling sad in reaction to an unpleasant event. A sad or depressed mood is only one of the many signs and symptoms of clinical depression. Clinical depression is a collection of symptoms that last for at least two weeks and interfere with functioning. There are several types of clinical depression, the most common being major depressive disorder. When people refer to clinical depression they are usually referring to major depressive disorder.
Major depressive disorder is diagnosed when a person experiences a minimum of five of the following symptoms every day, or nearly every day, for at least two weeks:
Many people with depression also experience high levels of anxiety or strong feelings of anger. Physical problems and concerns about one's health are common. Depressed individuals often complain of frequent headaches or back aches. Because depression is associated with several physical problems (including loss of appetite, sleep disturbance and fatigue) many individuals first go to their family doctor for treatment.
The majority of individuals with depression also have another psychiatric disorder such as panic disorder, posttraumatic stress disorder, alcoholism or an eating disorder. When these other disorders are not recognized the treatment of depression may be less effective. In bipolar disorder (manic-depression) the depressed person has also had periods in their life during which they felt extremely high, euphoric or irritable along with other symptoms or mania or hypomania.
Dysthymic disorder is a mild, chronic form of depression that lasts at least two years, during which time the person feels depressed on at least half the days and experiences depressed mood and at least two other symptoms of depression. Dysthymic disorder is like having a depressive personality. It is generally milder than major depressive disorder. Many individuals with dysthymic disorder have periods when they feel more severely depressed, at which time they may have a spell of major depressive disorder. Individuals with both types of depression are said to have double depression.