In the two decades following the Second World War, depression was considered a relatively rare disorder, more likely to be experienced by hospitalized patients than otherwise healthy people. Today, however, the Centers for Disease Control and Prevention estimates that 9.1 percent of adults in the United States are currently experiencing depression. A recent editorial in Nature claimed that “measured by the years that people spend disabled, depression is the biggest blight on human society — bar none.” What accounts for this change?
It will help to identify two broad periods in psychiatry’s standard conception of depression: before 1980, when psychoanalysis still held sway, and after 1980, when depression became defined according to symptom-based classification. These two periods are marked by contrasting criteria for diagnosis in the DSM (Diagnostic and Statistical Manual of Mental Disorders), the “bible” of clinical psychiatry published by the American Psychiatric Association. While the use of the DSM in the everyday practice of clinical psychiatry varies greatly and some psychiatrists hardly use it at all, it standardizes definitions of mental disorders and supplies a lingua franca for research, thereby providing a basis for measuring the prevalence of mental disorders and agreeing on their diagnoses.
The change that occurred in 1980 was pivotal for two reasons: first, it introduced a qualitatively different notion of depression, one that focused on overt symptoms rather than internal psychological stresses; second, in ignoring patient history and social context as criteria for diagnosis, it unintentionally led to an increase in the number of diagnoses.
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