Depression. Aaron T. Beck, M.D.

has been used to designate a discrete nosological entity. The term has generally been qualified by some adjective to indicate a particular type or form, as for example: reactive depression, agitated depression, or psychotic-depressive reaction. When conceptualized as a specific clinical entity, depression is assumed to have certain consistent attributes in addition to the characteristic signs and symptoms; these attributes include a specifiable type of onset, course, duration, and outcome.

      One such classification system, the diagnostic manual of the American Psychiatric Association (APA),⁵ illustrates some of these aspects. The APA categorizes the mood disorders into (1) depressive disorders (unipolar depression) and (2) bipolar disorders. In the former, there is no history of a manic or hypomanic episode, and in the latter there is such a history.

      The depressive disorders include major depressive disorder and dysthymic disorder. Major depressive disorder is defined by one or more major depressive episodes. Such episodes include 2 weeks of depressed mood or loss of interest, along with a minimum of four additional depression symptoms. Dysthymic disorder is defined in part by at least 2 years of low-level depressed mood, where the person is depressed for more days than not. The bipolar disorders are usually accompanied by major depressive episodes, and are divided into two types, Bipolar I and Bipolar II disorder.⁵ The classification of the mood disorders will be considered in more detail in Chapter 4.

      In medicine, a clinical entity or disease is assumed to be responsive to specific forms of treatment (not necessarily discovered as yet) and to have a specific etiology. There is a considerable body of evidence indicating that the clinical entity depression responds to certain drugs and/or electroconvulsive therapy (ECT), but there is no consensus as yet regarding its etiology. This issue will be further considered in Part II, “Experimental Aspects of Depression.”

Depression and Normal Moods

      There is little agreement among authorities regarding the relationship of depression to the changes in mood experienced by normal individuals. The term mood is generally applied to a spectrum of feelings extending from elation and happiness at one extreme, to sadness and unhappiness at the other. The particular feelings encompassed by this term, consequently, are directly related to either happiness or sadness. Subjective states, such as anxiety or anger, that do not fit into the happiness-sadness categories are not generally included. Some authors¹⁴ believe that all individuals have mood swings and that normal individuals may have “blue” hours or “blue” days. This belief has been supported by systematic studies of oscillations in mood in normal subjects.¹⁵

      The episodes of low mood or of feeling blue experienced by normal individuals are similar in a number of ways to the clinical states of depression. First, there is a similarity between the descriptions of the subjective experience of normal low mood and of depression. The words used to describe normal low mood tend to be the same used by depressives to describe their feelings— blue, sad, unhappy, empty, low, lonely. It is possible, however, that this resemblance may be due to depressed patients’ drawing on familiar vocabulary to describe a pathological state for which they have no available words. Some patients, in fact, state that their feelings during their depressions are quite distinct from any feelings they have ever experienced when not in a clinical depression.

      Second, the behavior of the depressed patient resembles that of a person who is sad or unhappy, particularly in the mournful facial expression and the lowered voice. Third, some of the vegetative and physical manifestations characteristic of depression are occasionally seen in individuals who are feeling sad but who would not be considered clinically depressed. A person who has failed an examination, lost a job, or been jilted may not only feel discouraged and forlorn, but also experience anorexia, insomnia, and fatigability. Finally, many individuals experience blue states that seem to oscillate in a consistent or rhythmic fashion, independently of external stimuli, suggestive of the rhythmic variations in the intensity of depression.¹⁵

      The resemblance between depression and the low mood of normals has led to the concept that the pathological is simply an exaggeration of the normal. On the surface, this view seems plausible. As will be discussed in Chapter 2, each symptom of depression may be graded in intensity along a dimension, and the more mild intensities are certainly similar to the phenomena observed in normal individuals who are feeling blue.

      In support of the continuity perspective, Hankin et al.¹⁶ used Meehl’s¹⁷ taxometric procedures to examine the structure of depression in a sample of children and adolescents. Taking into account the skewness of depressive symptoms, the authors reported youth depression to be a dimensional, not categorical, construct. In discussing the implications of their findings, Hankin et al.¹⁶ point out that by using continuously distributed scores, the statistical power of the research is enhanced, thus aiding the ability of researchers to ascertain correctly the true causes and consequences of depression.

      Similar to the findings of Hankin et al.,¹⁷ Haslam and Beck¹⁸ used taxometric procedures to test for discreteness (discontinuity) of 5 hypothesized subtypes of major depression, including endogenous, sociotropic, autonomous, self-critical, and hopelessness forms. The study used self-reported symptom and personality profiles of 531 consecutively admitted outpatients diagnosed with major depression. The features of the respective subtypes were not found to covary as predicted, except for the endogenous subtype.¹⁸

      It could be contended that many pathological states that seem to be on a continuum with the normal state are different in their essential character from the normal state. To illustrate this, an analogy may be made between the deviations of mood and deviations of internal body temperature. While pronounced changes in body temperature are on the same continuum as are normal temperatures, the underlying factors producing the large deviations are not an extension of the normal state of health: A person may have a disease, for example, typhoid fever, that is manifested by a serial progression in temperature and yet is categorically different from the normal state. Similarly, the deviation in mood found in depression may be the manifestation of a disease process that is distinct from the normal state.

      There is no general consensus among the authorities regarding the relation of depression to normal mood swings. Some writers, notably Kraepelin and his followers, have considered depression a well-defined disease, quite distinct from normal mood. They have postulated the presence of a profound biological derangement as the key factor in depression. This concept of a dichotomy between health and disease has generally been shared by the somatogenic school. The environmentalists seem to favor the continuity hypothesis. In their view, there is a continuous series of mood reactions ranging from a normal reaction to an extreme reaction in a particularly susceptible person. The psychobiological school founded by Adolph Meyer tends to favor this view.

      The ultimate answer to the question whether there is a dichotomy or continuity between normal mood and depression will have to wait until the question of the etiology of depression is fully resolved.

      Chapter 2

      Symptomatology of Depression

Previous Systematic Studies

      As stated in Chapter 1, there has been remarkable consistency in the descriptions of depression since ancient times. While there has been unanimity among the writers on many of the characteristics, however, there has been lack of agreement on many others. The core signs and symptoms such as low mood, pessimism, self-criticism, and retardation or agitation seem to have been universally accepted. Other signs and symptoms that have been regarded as intrinsic to the depressive syndrome include autonomic symptoms, constipation, difficulty in concentrating, slow thinking, and anxiety. In 1953, Campbell¹ listed 29 medical manifestations of autonomic disturbance, among which the most common in manic depressives were hot flashes, tachycardia, dyspnea, weakness, head pains, coldness and numbness of the extremities, frontal headaches, and dizziness.

      Very