Germs and Magic Bullets
One syndrome, one caise; many syndromes, many causes: these options suggested not just different etiological hypotheses, but opposing theoretical approaches to the understanding of human illness. Indeed, one of the most intriguing aspects of the early popularity of the immune overload hypothesis was that so many clinicians would readily forsake the approach to disease causation frequently described as the cornerstone of contemporary biomedicine: the principle of "one disease, one cause, one cure." As Allan Brandt has expressed it: "In this paradigm, individuals become infected with a parasite that causes dysfunction of some sort; disease is defined as a deviation from a biological norm. Social conditions, environmental phenomena, and other variables are generally discounted as causes of disease. The physician dispenses 'magic bullets' that restore the patient to health."
Ever since the bacteriological revolution of the late nineteenth century, when germs replaced "miasmas" as the preferred explanation for illness, medical research typically has focused on the discovery of discrete microbial causes for specific diseases. To be more precise, two separate assumptions have been welded together: that most illnesses have a single, fundamental cause, rather than multiple necessary causes; and that the search for the cause of illness should focus primarily on microbes, very secondarily on lifestyle issues, and only incidentally on environmental causes related to the larger organization of the society. Of course, the monocausal/microbial approach has always had its critics. Writing in 1959, René Dubos characterized the "doctrine of specific etiology" as "unquestionably the most constructive force in medical research for almost a century," but noted that "few are the cases in which it has provided a complete account of the causation of disease." Citing the failures, "despite frantic efforts," to find cures for diseases such as cancer and mental illnesses, Dubos argued that the "search for the cause may be a hopeless pursuit because most disease states are the indirect outcome of a constellation of circumstances. …"
Modern-day epidemiologists, more open to multicausal approaches to disease, may speak of a "web of causation" or may endorse "ecological" and "synergistic" models of illness that emphasize the
complex interrelationships among environmental and host factors. But in laboratories, examining rooms, and medical school classrooms, the doctrine of specific etiology holds sway. Many analysts have seen in the monocausal/microbial model of disease the clue to medicine's ideological function within a capitalist society: it encourages people to attribute their illnesses to invisible particles rather than to occupational hazards or defects of social organization. But to understand why clinicians and researchers themselves reach for such explanations, the suggestions of sociologist Andrew Abbott may be more to the point.
First, the germ theory of disease focuses public attention on medicine's greatest triumphs and away from arthritis, heart disease, cancer, and other chronic problems that have proven less amenable to therapeutic success. Second, one of the chief legitimating values of medicine (like other professions) is its perceived efficiency; and as opposed to environmental explanations, monocausal/microbial ones lend themselves to neat and straightforward solutions ("Take two pills every four hours"). The search for microbes enhances the power of laboratory researchers, who alone have the tools to conduct it. The search for environmental causes is, by contrast, frequently beyond their ken. In short, the commonly expressed preference of clinicians and biomedical researchers for simple, monocausal, microbial models may in an immediate sense have less to do with medicine's role in legitimating society than with doctors' and scientists' roles in legitimating scientific medicine.
In light of the prevailing explanatory preference, early clinical fascination with "the homosexual lifestyle" is all the more noteworthy. Of course, perceptions that illness is linked to lifestyle have become more common in recent years, with increasing attention to the relation between such factors as stress or eating habits and the development of various diseases. But to the extent that doctors endorsed a multicausal lifestyle model, they were going against the prevailing medical currents. It is well worth asking whether they would have been as likely to do so had it not been for the perception that "the gay lifestyle" was peculiarly laden with a potential for medical hazard.