We found significant drinking status × time interactions in a number of distinct and reproducible brain regions commonly associated with response inhibition. Prior to initiating substance use, adolescents who initiated heavy use showed less BOLD activation during inhibitory trials in frontal regions, including the bilateral middle frontal gyri, and non-frontal regions, including the right inferior parietal lobule, putamen, and cerebellar tonsil, compared with those who continued to abstain from alcohol use. This pattern of hypoactivity among youth who later initiated heavy drinking during response inhibition is consistent with studies showing decreased activity during response inhibition predicts later alcohol use and substance use . Indeed, change in BOLD response contrast over time in the right middle frontal gyrus was associated with lifetime alcohol drinks at follow-up. Together, these findings provide additional evidence for the utility of fMRI in identifying neural vulnerabilities to substance use even when no behavioral differences are apparent. At follow up, adolescents who transitioned into heavy drinking showed increasing brain activation in the bilateral middle frontal gyri, right inferior parietal lobule, and left cerebellar tonsil during inhibition; whereas, non-drinking controls exhibited decreasing brain activation in these brain regions. These regions have been implicated in processes of stimulus recognition, working memory, and response selection , all of which are critical to successful response inhibition. Indeed, neuroanatomical models of inhibitory control highlight the importance of frontoparietal attentional control and working memory networks . These models posit that inhibition and cognitive control involve frontoparietal brain regions when detecting and responding to behaviorally relevant stimuli. Thus,drying cannabis findings suggest that heavy drinkers recruit greater activity in these neural networks in order to successfully inhibit prepotent responses.
Given the longitudinal nature of the current study, it is important to consider our findings in the context of typical adolescent neural maturation. During typical neural maturation, adolescents exhibit less activation over time, as neural networks become more refined and efficient . Adolescents who transitioned into heavy drinking showed the opposite pattern – increasing activation despite similar performance, suggesting that alcohol consumption may alter typical neural development. The current findings should be considered in light of possible limitations. Although heavy drinking and non-drinking youth groups were matched on several baseline and follow-up measures, heavy drinking youth reported more cannabis, nicotine, and other illicit drug use at follow-up. Differential activation remained significant after statistically controlling for lifetime substance use and such differences may contribute to our findings. Further, simultaneous substance use might be associated with these results. Future research should explore the effects poly substance use during the same episode compared to the effects of heavy drinking on neural responses. It is also important to note that adolescence is a period of significant inter-individual differences in neural development, and as such, we matched self-reported pubertal development and age at baseline and follow-up to address this issue. For the current sample, histograms of age distributions at baseline and follow-up are provided in Online Resource 1. Again, our groups were well matched on these variables; however, additional longitudinal research to examine the effects puberty and hormonal changes on neural functioning and response inhibition are needed. In summary, the current data suggest that pre-existing differences in brain activity during response inhibition increase the likelihood of initiating heavy drinking, and initiating heavy alcohol consumption leads to differential neural activity associated with response inhibition.
These findings make a significant contribution to the developmental and addictive behaviors fields, as this is the first study to examine neural responses differences during response inhibition prior to and following the transition into heavy drinking among developing adolescents. Further, we provide additional support for the utility of fMRI in identifying neural vulnerabilities to substance use even when no behavioral differences are apparent. Identifying such neural vulnerabilities before associated behaviors emerge provides an additional tool for selecting and applying targeted prevention programs. Given that primary prevention approaches among youth have not been widely effective, it is possible that targeted prevention programs for youth who are at greatest neurobiological risk could be a novel, effective approach. As such, our findings provide important information for improving primary prevention programs, as well as answering the question of whether neural differences predate alcohol initiation or whether differences arise as a consequence of alcohol use.Although researchers in sociology, cultural studies, and anthropology have attempted, for the last 20 years, to re-conceptualize ethnicity within post-modernist thought and debated the usefulness of such concepts as “new ethnicities,” researchers within the field of alcohol and drug use continue to collect data on ethnic groups on an annual basis using previously determined census formulated categories. Researchers use this data to track the extent to which ethnic groups consume drugs and alcohol, exhibit specific alcohol and drug using practices and develop substance use related problems. In so doing, particular ethnic minority or immigrant groups are identified as high risk for developing drug and alcohol problems. In order to monitor the extent to which such risk factors contribute to substance use problems, the continuing collection of data is seen as essential.
However, the collection of this epidemiological data, at least within drug and alcohol research, seems to take place with little regard for either contemporary social science debates on ethnicity, or the contemporary on-going debates within social epidemiology on the usefulness of classifying people by race and ethnicity . While the conceptualization of ethnicity and race has evolved over time within the social sciences, “most scholars continue to depend on empirical results produced by scholars who have not seriously questioned racial statistics” . Consequently, much of the existing research in drug and alcohol research remains stuck in discussions about concepts long discarded in mainstream sociology or anthropology, yielding robust empirical data that is arguably based on questionable constructs . Given this background, the aim of this paper is to outline briefly how ethnicity has been operationalized historically and continues to be conceptualized in mainstream epidemiological research on ethnicity and substance use. We will then critically assess this current state of affairs, using recent theorizing within sociology, anthropology, and health studies. In the final section of the paper, we hope to build upon our ”cultural critique” of the field by suggesting a more critical approach to examining ethnicity in relation to drug and alcohol consumption. According to Kertzer & Arel , the development of the nation states in the 19th century went hand in hand with the development of national statistics gathering which was used as a way of categorizing populations and setting boundaries across pre-existing shifting identities. Nation states became more and more interested in representing their population along identity criteria, and the census then arose as the most visible means by which states could depict and even invent collective identities . In this way, previous ambiguous and context-dependent identities were, by the use of the census technology, ‘frozen’ and given political significance. “The use of identity categories in censuses was to create a particular vision of social reality. All people were assigned to a single category and hence conceptualized as sharing a common collective identity” , yet certain groups were assigned a subordinate position. In France, for example, the primary distinction was between those who were part of the nation and those who were foreigners, whereas British, American, and Australian census designers have long been interested in the country of origin of their residents. In the US, the refusal to enfranchise Blacks or Native Americans led to the development of racial categories, and these categories were in the US census from the beginning. In some of the 50 federated states of the US, there were laws,curing cannabis including the “one drop of blood” rule that determined that to have any Black ancestors meant that one was de jure Black . Soon a growing number of categories supplemented the original distinction between white and black.
Native Americans appeared in 1820, Chinese in 1870, Japanese in 1890, Filipino, Hindu and Korean in 1920, Mexican in 1930, Hawaiian and Eskimo in 1960. In 1977, the Office of Management and Budget , which sets the standards for racial/ethnic classification in federal data collections including the US Census data, established a minimum set of categories for race/ethnicity data that included 4 race categories and two ethnicity categories . In 1997, OMB announced revisions allowing individuals to select one or more races, but not allowing a multiracial category. Since October 1997, the OMB has recognized 5 categories of race and 2 categories of ethnicity . In considering these classifications, the extent to which dominant race/ethnic characterizations are influenced both by bureaucratic procedures as well as by political decisions is striking. For example, the adoption of the term Asian-American grew out of attempts to replace the exoticizing and marginalizing connotations of the externally imposed pan-ethnic label it replaced, i.e. “Oriental”. Asian American pan-ethnic mobilization developed in part as a response to common discrimination faced by people of many different Asian ethnic groups and to externally imposed racialization of these groups. This pan-ethnic identity has its roots in many ways in a racist homogenizing that constructs Asians as a unitary group , and which delimits the parameters of “Asian American” cultural identity as an imposed racialized ethnic category . Today, the racial formation of Asian American is the result of a complex interplay between the federal state, diverse social movements, and lived experience. Such developments and characterizations then determine how statistical data is collected. In fact, the OMB itself admits to the arbitrary nature of the census classifications and concedes that its own race and ethnic categories are neither anthropologically nor scientifically based . Issues of ethnic classification continue to play an important role in health research. However, some researchers working in public health have become increasingly concerned about the usefulness or applicability of racial and ethnic classifications. For example, as early as 1992, a commentary piece in the Journal of the American Medical Association, challenged the journal editors to “do no harm” in publishing studies of racial differences . Quoting the Hippocratic Oath, they urged authors to write about race in a way that did not perpetuate racism. However, while some researchers have argued against classifying people by race and ethnicity on the grounds that it reinforces racial and ethnic divisions; Kaplan & Bennett 2003; Fullilove, 1998; Bhopal, 2004, others have strongly argued for the importance of using these classifications for documenting health disparities . Because we know that substantial differences in physiological and health status between racial and ethnic groups do exist, relying on racial and ethnic classifications allows us to identify, monitor, and target health disparities . On the other hand, estimated disparities in health are entirely dependent upon who ends up in each racial/ethnic category, a process with arguably little objective basis beyond the slippery rule of social convention . If the categorization into racial groups is to be defended, we, as researchers, are obligated to employ a classification scheme that is practical, unambiguous, consistent, and reliable but also responds flexibly to evolving social conceptions . Hence, the dilemma at the core of this debate is that while researchers need to monitor the health of ethnic minority populations in order to eliminate racial/ethnic health disparities, they must also “avoid the reification of underlying racist assumptions that accompanies the use of ‘race’, ethnicity and/or culture as a descriptor of these groups. We cannot live with ‘race’, but we have not yet discovered how to live without it” . In mainstream drug and alcohol research, traditional ethnic group categories continue to be assessed in ways which suggest little critical reflection in terms of the validity of the measurement itself. This is surprising given that social scientists since the early 1990s have critiqued the propensity of researchers to essentialize identity as something ’fixed’ or ’discrete’ and to neglect to consider how social structure shapes identity formation. Recent social science literature on identity suggests that people are moving away from root edidentities based on place and towards a more fluid, strategic, positional, and context-reliant nature of identity . This does not mean, however, that there is an unfettered ability to freely choose labels or identities, as if off of a menu .