When a patient has clinical depression, she has symptoms like sadness and anger that interfere in her life. Not all forms of depression are the same: each type of depression has different diagnostic criteria, such as the duration and number of symptoms. The National Institutes of Health (NIH) states that major depression, atypical depression and dysthymia are the most common forms of depression. Another depressive disorder, seasonal affective disorder, occurs only during certain times of the year.
Major depression is one type of depression that occurs in both children and adults, though it is more prevalent in women, according to the NIH. To be diagnosed with major depression, the patient must have five or more symptoms of depression that last for at least two weeks. Like other psychiatric disorders, these symptoms must be a change in the person’s normal mood and behavior, and must interfere in her ability to function. Examples of major depression symptoms include agitation, problems concentrating, sleeping difficulties, changes in appetite and weight, feeling hopeless or worthless, fatigue, withdrawal from once enjoyed activities, and suicidal thoughts. If, however, the patient has only two to four symptoms, she is diagnosed with minor depression.
The NIH states that one-third of patients with depression are diagnosed with atypical depression. The main diagnostic criteria of atypical depression is mood reactivity, where the patient’s mood either improves or deteriorates in response to an event; a patient with major depression, on the other hand, only has a depressed mood. In addition to the mood reactivity, the patient must have two or more of the following symptoms: a strong reaction to rejection, overeating, oversleeping and a heavy feeling in the limbs.
Dysthymia is a chronic form of depression that affects five percent of the population, according to the NIH. A patient can have just dysthymia, or dysthymia combined with another form of depression, like major depression, or a psychiatric disorder. To be diagnosed with dysthymia, the patient must have a low mood for at least two years and two other symptoms, like poor concentration, feeling hopeless, low self-esteem, fatigue, changes in appetite and sleeping problems.
Seasonal Affective Disorder
Seasonal affective disorder (SAD) is a type of depression that occurs during the winter, though a rare form of SAD occurs during the summer, according to the NIH. For a patient to have SAD, symptoms must be present for at least two years, and he cannot have depressive episodes at other points of the year. Symptoms that distinguish SAD from other depressive disorders include decreased energy and concentration in the afternoon, lethargic movement, excessive daytime sleepiness, and carbohydrate cravings.