Research on CAM faces challenges similar to those inherent in conventional clinical trials, such as participant self-selection bias and parsing the effect of the patient–provider relationship, although these challenges may be exacerbated when studying CAM. Additional research challenges include the heterogeneity of CAM systems, the use of diverse diagnostic schemes that may not overlap with those of conventional medicine, the use of individualized multimodal treatments, and the simultaneous emphasis on patient-centered, global and preventive outcomes.
While many individuals in the United States may self-medicate with dietary supplements, other patients seek care from learned practitioners of traditional systems of medicine including Ayurveda from India, Kampo from Japan, Traditional Chinese Medicine (TCM), Native American medicine in all its variations, and more recently developed systems such as homeopathy, naturopathic medicine, and chiropractic. Most types of CAM are relatively unregulated in the United States, with only five (acupuncture, chiropractic, homeopathy, massage, and naturopathy) licensed in three or more states. Even with the regulation provided by licensure, the substantial heterogeneity found within these traditions contributes to the difficulty of translating CAM practice into CAM research.
A primary research challenge is rooted in the tendency of CAM practices to individualize for the patient, not the disease. As a result, treatment may vary for individual patients presenting with the same conventional diagnosis. For example, an acupuncturist who sees 2 patients with migraine headache may tailor their treatments quite differently, after making decisions on the selection of acupuncture points, the depth of needle insertion, and the frequency and scheduling of treatment. These choices are made on a patient-by-patient basis, informed by each patient's specific strengths, weaknesses, and needs. A research investigator must make similar decisions in designing a randomized controlled trial (RCT) for acupuncture. Unless these choices are made in an evidence-based fashion, the acupuncture trial may be considered compromised by some methodologists. The investigator must decide, for example, whether a standardized acupuncture protocol or individually prescribed acupuncture, or a combination thereof, will be delivered in an RCT. Implicitly, this choice entails either compromising traditional acupuncture practice or straining the validity of the medical model RCT originally designed to test the effect of a single intervention on an outcome or many independent interactions.
The translation of a type of CAM as practiced clinically into research has often meant streamlining a complex healing system into a simplified intervention. As a result, most research has investigated only one modality at a time within the wider rubric of a traditional system of medicine. For instance, there are hundreds of studies examining the efficacy of acupuncture alone for treating asthma, pain, hypertension, or nausea. Yet, in real practice, acupuncture would be just one of an arsenal of interventions used by a licensed acupuncturist, including botanical potions, cupping, dietary changes, exercise therapy (e.g., t'ai chi or qigong), moxibustion, and Chinese massage. The same can be said of assessing yoga, or a single botanical, or meditation alone, given that all are merely single components of larger, complex systems of medicine. The research challenge of whether to study a single component or a combination of many modalities echoes the methodological issue of choosing individualized versus standardized CAM treatment for an RCT. The investigator is faced with either designing a trial with a single modality that does not reflect true clinical practice accurately or, alternatively, undertaking a multifaceted intervention trial that complicates interpretation from a conventional perspective.
Recognizing the difficulties involved with conducting multifaceted intervention trials, observational studies may provide an alternative approach to generating data on CAM. Observational studies could provide information on the numbers and types of patients who use CAM therapies, and elucidate issues regarding treatment delivery, dosage, relevant side-effects, and patient outcomes. Such studies may inform the design of further intervention studies by providing an estimate of treatment effect-size. Observational studies also may be helpful for summarizing the use of CAM nosologies that differ from conventional diagnosis of illness.
To date, little research has examined CAM interventions using the nosologies or diagnostic schemes associated with particular CAM systems. In general, CAM diagnostic schemes are complex, individualized, and prone to intra- and interpractitioner variability. However, it might prove beneficial to investigate CAM therapies using them, especially when the conventional medical diagnosis is unspecific and prone to subjective interpretation. In the case of fibromyalgia (FM), temporomandibular disorder, or irritable bowel syndrome (IBS), for example, the addition of a CAM diagnostic scheme to inform clinical-trial inclusion criteria might allow more specific classification of the disease or condition and increase the homogeneity of the patient population included in the study.
Assessing the role of the placebo or meaning effect in CAM therapies, and controlling for it, has been another challenge for researchers. CAM treatments typically involve extended and intensive interactions between patients and practitioners, which greatly increase the possibility of nonspecific effects. At the same time, the patient–provider relationship itself is considered a key element of many CAM therapies. As a result, finding appropriate placebos or shams for treatments such as TCM and homeopathy—with their extensive provider–patient diagnostic interviews—or chiropractic, massage therapy, acupuncture, or complex herbal mixtures, remains a challenge. Double-blinding of the interventions may not be possible because an experienced practitioner will know which treatment is sham and which is true. The practitioner, in turn, may consciously or unconsciously convey this information to the patient, undermining the trial design. Variations in practice also affect the choice of a placebo or sham. For instance, superficial insertion of acupuncture needles at valid acupuncture points has been used as a sham control in many acupuncture trials. Yet, the Japanese school of acupuncture advocates such superficial needling as an effective treatment. More innovative placebo and sham controls are required for future CAM RCTs.
Selecting appropriate outcome measures in CAM research may be challenging, and is influenced by the holistic view of health often imbued in traditional medicine systems. CAM providers emphasize the treatment of the whole patient by addressing the totality of the person's physical, mental, and spiritual attributes, rather than focusing on a specific pathogenic process. What is intrinsic to the whole-person approach is a focus on therapies that are designed to stimulate a patient's recuperative powers, correct an imbalance among individual organs or physiologic systems, or even enhance a patient's ability to relate well to other individuals, society, or the environment. As such, a coordinated set of interventions are often chosen for their interactive synergistic roles in treating what is conceived of as one central or global disturbance within the patient. Because of this focus on the total person, CAM providers often measure treatment success in terms of holistic outcomes rather than focusing on curing a given disease or disorder. In this view, global improvement is more important than specific results, and it is possible for a patient to be healed without the disease being cured, although the intent is always to do both.
The unique characteristics of CAM systems described here affect the types of questions that might be asked in future research. For instance, instead of asking whether a specific herb is efficacious for joint pain, it might be more appropriate to ask for whom, and in what environmental context, a given treatment package is effective. When answering this question, outcome measures that capture overall benefit to the patient need to be considered.