单选题 . 
    Like medical doctors, mental health professionals often use diagnosis as a way of categorizing patients and their problems. The use of diagnoses can, at times, help guide treating professionals as to the nature of the problems a patient faces, the origins of those problems, and potential treatment options. Diagnosis can also sometimes be used to straightjacket patients into ill-defined and ill-fitting categories that lend a scientific appearance to socially constructed biases. For example, a diagnosis of major depressive disorder is often used by psychiatrists and managed care companies as an argument that a person has a "biologically-based mental illness" and thus must receive a biological treatment, such as antidepressant drugs or, more rarely, electroconvulsive treatment. The assignment of the diagnosis mandates a treatment prescription despite considerable controversy among researchers and practitioners as to the relative effectiveness of drug treatment versus psychotherapy.
    Some conditions bear enough of the characteristics usually associated with illness to be reasonably referred to as mental illnesses. But the jury is still out as to the extent organic factors play in schizophrenia. While there is increasing evidence of organic factors-including genetic factors and illness in the pregnant mother—playing a role in this condition, no organic factors at this point are known to be either necessary or sufficient. Similarly, there exists evidence suggesting that schizophrenia is a condition qualitatively distinct from other modes of living. On the other hand, there exists evidence questioning this view of schizophrenia as a clearly distinct illness. There is evidence that schizophrenia is the extreme end of a larger spectrum of "conditions." And environmental factors clearly play a role in the prospects for the development of the condition and in its course.
    If one concludes that schizophrenia is, indeed, largely a biological condition, then it would be reasonable to describe it as an illness. But what if one decides that environmental factors play a large role?
    Once we get beyond the clearly organic conditions, the category of mental illness becomes metaphorical. There is nothing wrong with this. People make sense of the world largely through metaphors. The illness metaphor can be illuminating, but it can also be blinding. The question is whether applying it to the emotional problems and issues people face reveals hidden aspects, or covers over important characteristics. Thus, mental illnesses are like other physical illnesses in that they often appear to be involuntary and they can interfere with normal functioning and/or cause distress.
    However, many uses of the mental illness construct ignore its metaphorical quality. Thus, it is sometimes presumed without question that anything diagnosed as a mental illness should be treated, despite the fact that the majority of those identified in epidemiological studies as having such a condition do not seek treatment. Others go so far as to form an equation whereby mental illness equals illness, illness means physical condition, and physical condition requires physical treatment. This logic underlies much of the overuse of medications and the downplaying of psychotherapy for problems in living that characterizes the last few decades.
    Each of the three links in this equation is fallacious, of course. As I discussed above, mental illness may resemble other illnesses in certain ways, but in most cases definitely is not same thing. Certainly, if one extends the concept of illness to include mental conditions with no obvious organic cause then illness does not mean physical condition and there is no necessary reason that it should be treated, much less treated by physical interventions.1.  The passage is mainly about ______.