The age of depression

The basic flaw, then, is that the DSM-IV fails to exclude from the disorder category sadness reactions to events other than death of a loved one that are intense enough to meet the DSM-IV's criteria but are still normal reactions. The age of depressive disorder in which we find ourselves today is partly an artifact of a logical error.

Community studies of depression

In a clinical assessment, the clinician can in principle override the DSM-IV diagnostic criteria for depression and judge that an individual satisfying the criteria nonetheless is having a normal reaction. But no such back-up validation procedure exists when questionnaires about symptoms are administered to community members to measure how much disorder exists in the general population. Thus invalid criteria have particular scope for mischief in such studies.

A vast extension of the application of the symptom-based concept of mental disorder occurred when DSM criteria became the basis for large epidemiological studies attempting to measure the extent of mental disorder among people in the community who are not undergoing mental-health treatment. Because from DSM-III onward diagnoses were based entirely upon symptoms, epidemiologists could easily construct lists of questions that could be used to determine whether a respondent met DSM criteria for disorder, including depressive disorders. Lay interviewers could administer such questionnaires, allowing researchers to obtain psychiatric diagnoses comparable to those a psychiatrist would obtain, without the prohibitive expense of psychiatric interviewers. The results would presumably provide good estimates of how much untreated mental disorder existed in the community. These estimates were intended to guide policy makers in allocating resources by establishing how much unmet need existed for psychiatric services. The decision to use objective measures of symptoms in community studies largely stems from considerations of practicality and cost, and an uncritical acceptance of the DSM's symptom-based criteria, not from independent tests showing these methods are accurate in identifying disorder.

Findings from two major national studies, the Epidemiological Catchment Area Study (ECA) conducted in the early 1980s and the National Co-Morbidity Study (NCS) conducted in the early 1990s are the basis for the estimates regarding the prevalence of mental disorder that are now widely cited in the scientific, policy, and popular literatures. The NCS estimates that about 5 percent of subjects had a current (30-day) episode of major depression, about 10 percent had this diagnosis in the past year, about 17 percent had an episode over their lifetime, and about 24 percent reported enough symptoms for a lifetime diagnosis of either major depression or a related disorder, dysthymia.

Are the many cases of putative major depression uncovered in community studies equivalent to treated clinical cases? The odds are against it. These studies follow the DSM in ignoring the context of symptoms, thus confounding ordinary sadness with genuine disorder without recourse to clinical judgment to correct the error. For example, in the ECA study the most common symptoms among those reporting symptoms are "trouble falling asleep, staying asleep, or waking up early" (33.7 percent), being "tired out all the time" (22.8 percent), and "thought a lot about death" (22.6 percent). College students during exam periods (particularly those studying existential philosophy), people who must work overtime, or those worrying about an important upcoming event could all experience these symptoms naturally. Thus conditions that neither respondents nor clinicians would consider reasons for entering treatment can nonetheless indicate disorder in community surveys. Moreover, the symptoms are required to last for only two weeks, allowing many transient and self-correcting symptoms to become the basis for diagnosis. While most studies do not report the context of symptoms, in one study of adolescent depression that did, the single greatest trigger for presumed depression was the breakup of a romantic relationship, suggesting that a potentially large proportion of "disorders" were actually misclassifications of normal responses.