ورود اقلیت در مطالعات کارآزمایی بالینی تصادفی اختلال پانیک

In 1993, the National Institutes of Health issued a mandate that funded research must include participation by racial and ethnic minority groups, and researchers were required to include in their proposals strategies by which they would achieve diversity in their samples. A methodological search for randomized clinical trials of panic disorder was conducted to evaluate ethnoracial differences in panic disorder symptoms, rates of minority inclusion in North American studies, and effective methods of minority recruitment. Less than half of the studies identified reported ethnic and racial data for their sample. Of the 21 studies that did report this information (n = 2687), 82.7% were European American/non-Hispanic White, 4.9% were African American/Black, 3.4% were Hispanic, 1.1% were Asian American, and 1.4% were another ethnicity. The remaining 6.5% was simply classified as other/non-White. The primary recruitment techniques utilized were clinical referral and advertising, but neither of these methods were correlated with improved minority participation, nor was the number of recruitment sites. As minorities are greatly underrepresented in panic disorder studies, reported treatment outcomes may not generalize to all ethnic and cultural groups. Researchers have not followed NIH guidelines regarding inclusion of special populations. Inclusion of minorities in future studies is needed to fully understand issues related to the treatment of panic disorder in non-White populations. Suggestions for improved recruitment of ethnoracial minorities are discussed.

Panic disorder, often accompanied by agoraphobia, is a serious anxiety condition, resulting in disability and distress. The National Comorbidity Survey Replication (NCS-R) indicates that in the past year, panic disorder criteria was met by 2.7% of the population, with 44.8% of that group exhibiting serious symptoms (Kessler, Chiu, Delmer, & Walters, 2005). Lifetime prevalence for panic disorder, with or without agoraphobia, is 4.7% (Kessler, Berglund, et al., 2005). The lifetime prevalence rates among racial/ethnic groups were greatest among those who identified as Hispanic (5.4%), followed by Non-Hispanic White (4.9%), and Non-Hispanic Black (3.1%; Breslau et al., 2006). Data from the Collaborative Psychiatric Epidemiology Studies (N = 16,711) revealed a similar pattern of panic disorder lifetime prevalence rates among White Americans (5.1%), Hispanic Americans (4.1%), African Americans/Black (3.8%), and Asian Americans (2.1%; Asnaani, Richey, Dimaite, Hinton, & Hofmann, 2010). The empirical literature pertaining to the epidemiology of panic disorder is further intriguing, since cultural factors are ostensibly ignored as evidenced by disparate interpretations for conclusions drawn in this area. For instance, epidemiological studies do not show a significant difference in the prevalence of panic disorder across ethnic and racial groups. However, accurate rates may be difficult to determine as North American studies of panic disorder and other anxiety disorders utilize tests and measures constructed from a predominantly European American or Western perspective, and may fail to capture culturally distinct symptoms of other ethnic groups. Research indicates that the cultural differences may manifest in the way that symptoms are described and experienced (Guarnaccia, 1997), and studies that comprise the National Institute of Mental Health Collaborative Psychiatric Epidemiology Surveys (CPES) mirror this sentiment. These reflect efforts to study ethnic and cultural differences in mental health and wellbeing of African Americans (NSAL), Hispanics and Asian Americans (NLAAS). Alegría, Vila, et al. (2004) note that, “The reliance on measures developed in our cultural context that do not take semantics and cultural variation into account, fosters false assumptions, attributional errors, and misleading interpretations, mostly due to the absence of a solid understanding of how to incorporate cross-cultural variation in measurement.” Others support this argument, citing America's growing minority population as reason to investigate panic disorder and other mental health problems in non-European American groups ( Alegría, Takeuchi, et al., 2004). Currently, there are 308.7 million people in the United States, and 13.6% of these are African American, 16.3% Hispanic or Latino American, and 5.6% Asian American, alone or in combination with some other racial group (Humes, Jones, & Ramirez, 2011). With the current lifetime prevalence of panic disorder, these numbers indicate that a considerable number of people from all ethnoracial groups are suffering from this disorder, making it an important public health concern. 1.2. Panic symptomatology in African American samples Although work with ethnic minority populations is undoubtedly burgeoning, the scope of the empirical work in this area remains relatively sparse. Though one may presume that panic symptoms generalize across cultures, some ethnoracial groups describe panic symptomatology differently than their European American counterparts. For example, African Americans report symptoms such as wooziness on the brain, swimming head, heart tremors, itching, seeing red, and blood on the breath (Horwath, Johnson, & Hornig, 1994). Moreover, many African Americans express anxiety symptomatology through somatic complaints with symptoms such as numbing and a decreased emphasis on cognitive processes, and lower levels of subjective nervousness (Barrera et al., 2010, Heurtin-Roberts et al., 1997 and Smith et al., 1999). Additionally, there is evidence that African Americans with panic disorder have more separation anxiety and social phobia than European Americans (Friedman, Hatch, & Paradis, 1994). Much of the information we have about panic disorder in African Americans comes from the work of Friedman and Paradis (2002), who, in a single study, found a high comorbidity of panic disorder with post-traumatic stress disorder and depression in African Americans. Along these lines, the researchers suggest that there is less self-blame and more spiritual dependence as a coping measure for the disorder. Last and most significantly they noted a higher incidence of sleep paralysis in African Americans, a phenomenon where, upon waking, an individual is unable to move and often experiences frightening hallucinations. Sleep paralysis is more common in African Americans, but the rate is particularly high in those with panic disorder (59%; Paradis et al., 1997 and Paradis and Freidman, 2005), indicating a connection between these symptoms that may be unique to African Americans. Given that a single investigation of panic disorder yielded these compelling results, it is plausible to conclude that other characteristics maybe found with further, culture-centered collaboration in this area of research. 1.3. Panic symptomatology in Hispanic samples Guarnaccia (1997) suggests that criteria and diagnostic symptoms need to be expanded to include potential factors relevant to minority groups. In examining anxiety in Hispanic Americans, Karno et al. (1989) attributed selective migration by less fearful individuals to increased rates of anxiety in Hispanics in the Los Angeles area when compared to their Mexican counterparts across the border, but the stress of migration itself and subsequent minority status in the US may also be factors. Other relevant findings surround the phenomenology of the culture-bound syndrome termed Ataques de Nervios ( American Psychiatric Association, 2000), which is similar to panic attacks but also may include uncontrollable anger or physical outbursts, described most often in Caribbean Hispanic cultures. The most common symptoms include dissociation, suicide attempts, fainting, seizures, shouting, crying, trembling, and heat in the chest ( Hinton, Lewis-Fernandez, & Pollack, 2009). These symptoms may be conceptualized as a type of stress-induced panic attack, with specific symptoms influenced by cultural expectations. This suggests that both cultural and psychosocial factors disparately influence the experience of panic in different ethnoracial groups. Initial research supports the DSM-IV distinction between panic attacks and Ataques de Nervios. However, the syndrome may occur at similar rates in both Hispanic and Non-Hispanic cultures ( Keough, Timpano, & Schmidt, 2009). 1.4. Panic symptomatology in Asian American samples Not surprisingly, research pertaining to anxiety disorders in Asian Americans is also sparse. The work that does exist, however, is promising and suggests that Asian Americans may experience anxiety at similar rates as their non-Hispanic White counterparts (Gee, 2004, Lee et al., 2001 and Okazaki, 2000). However, significant ambiguities continue to exist in the empirical literature pertaining to Asian Americans for many of the same reasons as other ethnic minority groups in the United States. For example, much of the literature to date has focused on social anxiety symptoms and attempts to distinguish between Western definitions of anxiety and Taijin Kyofusho (TKS), classified as a cultural bound syndrome found predominantly in individuals from Japanese decent (Kirmayer et al., 1995 and Kleinknecht et al., 1997). Since TKS is based on anxiety and fear surrounding not offending others, a sociocultural factor that is endemic to Asian cultures, examining these constructs is important. However, as with other ethnic minority groups, instruments to assess social anxiety do not include specific questions to identify this culture-bound syndrome. Therefore, the potential for culturally invalid assessment continues to remain a problem when assessing anxiety in Asian American populations, which may lead to misdiagnosis (Gee, 2004 and Lin and Cheung, 1999). Asian Americans have been found to report more somatic symptoms than non-Hispanic Whites (Lin & Cheung, 1999). Specifically, with respect to panic disorder, in one study Asian Americans were found to experience the symptoms of choking and terror more often than European Americans (Barrera et al., 2010). Asian patients experiencing psychological distress are more likely to report somatic symptoms to their health care providers rather than emotional symptoms, however, the literature continues to remain relatively silent as to whether there is a connection between panic disorder and somatization in Asian Americans (Lin & Cheung, 1999). Similar to the work with other ethnic minority groups, definitive conclusions are presently precluded due to the dearth of the empirical literature. Although beyond the scope of this review, it is presumed that other reasons for this ambiguity include cultural heterogeneity, differences in ethnic identity, lack of validation studies for measures of anxiety-related constructs in Asian populations, and other sociocultural factors. 1.5. Mandates for inclusion In an effort by the National Institute of Health to ensure that ethnic and racial minorities are adequately represented in research studies, Congress passed the NIH Revitalization Act of 1993. This act, and the redefining of sampling regulations, ensured that minorities and women were included for in representative numbers of all studies conducted or supported by the NIH ( USDHHS, 2002). The language of the Act states “there is an ethical importance of ensuring that recruitment is conducted in a manner that is fair to women, men and persons from minority populations so that no group is unduly burdened and that no group is unduly benefited” ( USDHHS, 2002, p. 3). In the same guideline, it is made clear that minority samples must be included in the study if “there is no clear-cut scientific evidence to rule out significant differences of clinical or public health importance among racial or ethnic groups or subgroups in relation to the effects of study variables” ( USDHHS, 2002, p. 25). By 1994, the NIH had revised its policy to require that women and minorities be included, and by 1995 the NIH refused to fund any project that did not adhere to these policies. Researchers were required to include in their grant proposals strategies by which they would achieve diversity in their samples. 1.6. Purpose of this investigation The authors of this investigation sought to determine the rates of inclusion of minorities in randomized clinical trials by compiling a review of the literature on panic disorder. We were interested in any specific findings of particular relevance to minorities in regards to treatment issues, such as whether certain treatments were more effective for specific ethnoracial groups. Our objective was to determine if the existing data on panic disorder is adequate to represent and generalize to all portions of the population. Because of smaller numbers in many samples, this generally means that minorities would have to be oversampled to ensure enough statistical power was available for any group differences to emerge. While this sets high expectations for any study, we can hope that at the very least, the samples for studies performed in the United States mirror the composition of the population, and we include Canada as it is not uncommon for large clinical trials have collection sites in both countries. Additionally, Canada has a similar culture and ethnographic makeup to the United States in its major provinces, albeit with somewhat fewer visible minorities (Statistics Canada, 2008). If minorities are not adequately represented, it is unclear whether results from these studies are applicable to all Americans. In addition, investigation of recruitment techniques and trial locations was conducted to attempt to determine successful and unsuccessful methods for recruiting adequate samples of minorities.