En caso de valor numérico, identificación de la unidad de medida en la que se

ternalized meanings that reflect shared cultural attitudes and values, including beliefs about what medicine is and how medicine works to alleviate symptoms or bring about healing. In Western cultures, biomedicine is the dominant ex- planatory model of health and illness. According to this view, medical and psy- chiatric disorders are constructed on the basis of recurring patterns of observable signs or symptoms that are causally linked to identifiable stresses. In conven- tional biomedicine, a diagnosis requires the confirmation of subjective symp- toms reported by patients and objective signs of pathology observed by physi- cians or other medically trained personnel. In contrast, diagnosis and assessment methods in alternative or complementary systems of medicine (e.g., Chinese medicine, Ayurveda, homeopathy) construct symptoms into disorders on the basis of criteria that are seldom congruent with core materialistic assumptions of contemporary biomedicine (Krippner 1995); many nonconventional systems of medicine are based on metaphysical assumptions about the nature of the human body in time and space, the role of consciousness in healing, and the primary influences of disparate psychological or biological factors in illness and health (“Defining and describing complementary and alternative medicine” 1997). Most CAM treatments assume the validity of one or more of the following mechanisms of action:

• Conventional biological processes, such as herbal medicines, aromatherapy, essential oils, and other natural substances including omega-3 essential fatty acids, minerals, vitamins, amino acids, and amino acid precursors

• Somatic manipulation or mind–body approaches, such as massage and exercise and mind–body approaches (e.g., yoga, qigong)

• Scientifically validated forms of energy or information, such as electroencephalogram biofeedback, other kinds of biofeedback using sound or light, electroconvul- sive therapy, transcranial magnetic stimulation, and bright-light exposure • Forms of “energy” or information that are not yet scientifically validated, such as

“subtle energy” assessment and treatment methods including healing touch and reiki, homeopathy, qigong, directed intention, prayer, and some mind– body practices

Conventional biomedicine has historically borrowed concepts from physics, chemistry, and biology (Hahn 1995). Basic understandings of sickness and health are often fundamentally disparate in different cultures, and the methods used to treat sickness in a given culture are constantly changing (Conrad et al. 1995; Fab- rega 1997). Contemporary biomedical models equate health and sickness with normal and abnormal biological functioning, respectively. This approach assumes that symptoms can be adequately characterized in terms of measurable changes in basic biological processes in the human body and reduces all health or illness phe- nomena to these processes. By extension, conventional Western medicine argues that human consciousness can be described in terms of neurophysiology. Bio- medical psychiatry has endorsed this model and the corollary that normal and pathological states of consciousness are reducible to basic neurophysiological or neurochemical processes. In this broad context, it has been argued that the claims of CAM are often capricious and lack scientific rigor. It has been suggested that there is “only scientifically proven.. .evidence-based medicine. ..or unproven medicine for which scientific evidence is lacking” (Fontanarosa and Lundberg 1998, p. 1618). However, many professional systems of medicine that originated in non-Western cultures do not accept the orthodox mode of explanation that Western scientific materialism assumes to be true (Kaptchuk and Eisenberg 2001a). This has resulted in important practical problems for researchers attempt- ing to reconcile methods and clinical evidence supporting nonconventional treat- ments with the basic physical or biological processes posited by Western science. In recent decades, biomedicine has reexamined many of its core premises in response to emerging theories in physics and the life sciences that call into ques- tion some of the basic tenets of contemporary Western science (Turner 1998). Novel theories in the domain of Western science are providing conceptual frameworks that may eventually yield orthodox explanations of certain noncon- ventional medical treatments. These new ways of seeing reality—including hu- man consciousness—include quantum field theory, complexity theory, and the theory of dissipative structures. Basic research on human consciousness using re- cent advances in functional brain imaging technologies, including quantitative electroencephalogram, functional magnetic resonance imaging, and positron emission tomography, will permit future Western researchers to design experi- ments capable of confirming or refuting claims of so-called energy healing

methods such as qigong. In the coming decades, some “energy” treatments now regarded as being alternative will probably become empirically validated by future research methods and accepted into mainstream medicine, whereas oth- ers will be refuted and the theories on which they are based will be proven false by emerging technologies, as have conventional treatments such as the insulin coma and prefrontal lobotomy. Other nonconventional treatments will proba- bly continue in widespread use on the basis of anecdotal evidence, despite the absence of confirmatory findings of a putative mechanism of action or a verifi- able therapeutic effect in Western-style research studies.

The rapid evolution in the conceptual foundations of Western science has led to renewed openness among conventionally trained physicians who are ad- vancing holistic models about the nature, causes, or meanings of illness, includ- ing a possible primary role of self-regulation or self-healing in physical and men- tal health; the interdependence of immunology, psychiatry, and neurology in symptom formation; and possibly other direct effects of stress, social support, and human consciousness on health and illness (Astin et al. 1998; Dacher 1996). The evolution in Western scientific theories has led many physicians to embrace concepts that have long been the domain of alternative medicine, including the central role of genetic and biochemical individuality in health and illness, the importance of a homeodynamic (in contrast to homeostatic) model of health as a state of dynamic balance, and the idea that most treatments do not cure illness but, more accurately, serve as catalysts for the body’s innate healing capacities. For example, McEwen (1998) posited a model of allostatic load as affecting a variety of health outcomes. Allostasis involves a resetting of stress response mechanisms in reaction to repeated stressors. The resulting allostatic load can produce impairment in stress response systems, thus affecting stress hormones such as cortisol and prolactin, immune function, and autonomic nervous system activity, resulting in chronic hyper- or hyporeactivity to stressors. Such dysreg- ulation can affect brain structure and function (McEwen 1999; Sapolsky 1996) and disease progression (Grippo and Johnson 2002; Sephton and Spiegel 2003; Sephton et al. 2000; Steptoe et al. 2003).

Growth of Complementary, Alternative, and