What are the different types of depression?
Several types of depression exist. Depressed (or irritable) mood or a loss of interest in pleasurable activities is characteristic of all types, and all types have to cause impairment in functioning. There are some differences in symptom presentation, however, and treatment approaches may vary somewhat. The different types of depression are
• Major depressive disorder
• Dysthymic disorder
• Seasonal affective disorder
• Bipolar depression
• Depressive disorder not otherwise specified
In major depression qualifiers can be added to the diagnosis, such as "atypical," "melancholic," or "postpartum onset." Such qualifiers describe a specific pattern of symptom presentation. For example, increased appetite, rejection sensitivity, and a sensation of heaviness of the limbs characterize an atypical major depressive episode. Melancholic depression is most associated with sleep and appetite loss and psychomotor retardation. It also is characterized by a phenomenon known as a diurnal variation of mood—feeling much worse in the morning with some improvement in mood by evening.
Major depression and dysthymic disorder are the most common forms of depression. Dysthymic disorder is more chronic with persistent sadness nearly daily for at least 2 years. In seasonal affective disorder the depressive symptoms are the same as in major depression but occur exclusively within one season (usually the winter). Bipolar depression is the depressed phase of a condition called bipolar disorder (see Question 19). In many cases the symptom presentation of depression does not fit the criteria as described in the DSM-IV-TR. Symptoms, however, may be causing impairment in functioning. The diagnosis of depressive disorder not otherwise specified can be used in those cases. Although the type of depression impacts the prognosis and treatment modality, in general, all types respond to a combination of medication therapy and talk therapy.
Are any blood tests or other tests available for depression?
No objective tests are available for depression. Some tests used in research protocols examine levels of certain stress hormones or look at brain functioning. These are research based only, however, and have no utility in clinical practice. Your doctor may order blood tests to check for any underlying conditions that may mimic depression such as low thyroid hormone. Blood tests or electrocardiograms may be ordered for baseline purposes, depending on the medication that is to be prescribed, because some medications may have effects on certain organ systems in the body.
Although not a required part of an evaluation, some clinicians use various rating scales and self-report forms to assist in the evaluation process. Scales may be useful in tracking the progression of the depression in a quantifiable way. Comprehensive diagnostic scales can guide the clinician in going through a differential diagnostic process to exclude other causes for the symptoms before establishing a diagnosis. Such scales may indeed establish a diagnosis of a depression, but they are based on the same clinical criteria used without a scale. These scales are mostly useful in research to establish reliability in diagnosis and to increase the validity of the study.
How do I know whether I have depression versus a "normal" reaction to a problem in my life?
Life events that are stressful can result in normal sadness as well as other symptoms similar to those present during a depressive episode. These symptoms may only last a few days. In the case of bereavement symptoms may last much longer. Bereavement, however, is a normal process. The duration of bereavement can vary between cultural groups. If, however, symptoms begin to prevent an individual from functioning socially or occupationally and academically and persist beyond a couple of months, especially if suicidal thinking is present, then the possibility of a depressive episode being present is much greater. An assessment by a mental health practitioner would be warranted in such circumstances. Table 1 outlines features that may help differentiate depression from normal sadness.
Table 1. Differentiating Depression From Normal Sadness
Increased intensity of symptoms
Increased length of symptoms
No change in mood with changes in external events
Decreased functioning at work/school/home
Although depression has a biologic basis, stressful life events often trigger its onset. Certain life events are considered more stressful than others. Divorce, death of a spouse, and death of a child are considered very stressful. Additional stressors include marital arguments, a new job, the presence of a serious personal illness, going to college, moving, marriage, and the birth of a child. Sometimes the accumulation of several mild stressors triggers a depressive episode. At one time it was assumed that there were two types of depression: endogenous (triggered from within, or "biologic") or exogenous (triggered from environmental circumstances). Such a distinction is generally not considered applicable anymore, because most depressions are triggered by environmental circumstances and are likely dependent on the person's genetic vulnerability. A comprehensive mental health evaluation typically identifies social stressors associated with the depression. Depending on the nature of the stressors, different treatment modalities may even be recommended (e.g., family therapy, couples counseling, group therapy).
Again, one reason so many people do not get treated for depression is because of the belief that the depression may be a normal reaction to a given situation. Sadness is a normal emotion and a normal reaction to many situations, but depression is a condition that adversely affects the entire body; left untreated, it can have significant consequences for the affected individual.
Sleep and appetite are adversely affected. The body may have reduced ability to fight infection. Depression can make recovery from stroke or heart attack more difficult. A greater risk exists for drug and alcohol abuse, which in turn can worsen depression and further impair functioning. Because of the risks of untreated depression, it is best to seek mental health consultation if there is any question of the possibility of depression.