Researchers from Germany used fMRI along with psychological and physiological measures to investigate the neural factors associated with the role of perceived discrimination in the development of psychopathology. “Ethnic minority individuals had significant correlations between perceived group discrimination and activation in perigenual ACC (anterior cingulate cortex) and ventral striatum,” the authors conclude. Results appear in JAMA Psychiatry.
Akdeniz, C.; Tost, H., Streit, F., Haddad, L.; Neuroimaging Evidence for a Role of Neural Social Stress Processing in Ethnic Minority–Associated Environmental Risk. JAMA Psychiatry. Online April 16, 2014. doi:10.1001/jamapsychiatry.2014.35
From the article:
Importance Relative risk for the brain disorder schizophrenia is more than doubled in ethnic minorities, an effect that is evident across countries and linked to socially relevant cues such as skin color, making ethnic minority status a well-established social environmental risk factor. Pathoepidemiological models propose a role for chronic social stress and perceived discrimination for mental health risk in ethnic minorities, but the neurobiology is unexplored.
Objective To study neural social stress processing, using functional magnetic resonance imaging, and associations with perceived discrimination in ethnic minority individuals.
Design, Setting, and Participants Cross-sectional design in a university setting using 3 validated paradigms to challenge neural social stress processing and, to probe for specificity, emotional and cognitive brain functions. Healthy participants included those with German lineage (n = 40) and those of ethnic minority (n = 40) from different ethnic backgrounds matched for sociodemographic, psychological, and task performance characteristics. Control comparisons examined stress processing with matched ethnic background of investigators (23 Turkish vs 23 German participants) and basic emotional and cognitive tasks (24 Turkish vs 24 German participants).
Main Outcomes and Measures Blood oxygenation level–dependent response, functional connectivity, and psychological and physiological measures.
Results There were significant increases in heart rate (P < .001), subjective emotional response (self-related emotions, P < .001; subjective anxiety, P = .006), and salivary cortisol level (P = .004) during functional magnetic resonance imaging stress induction. Ethnic minority individuals had significantly higher perceived chronic stress levels (P = .02) as well as increased activation (family-wise error–corrected [FWE] P = .005, region of interest corrected) and increased functional connectivity (PFWE = .01, region of interest corrected) of perigenual anterior cingulate cortex (ACC). The effects were specific to stress and not explained by a social distance effect. Ethnic minority individuals had significant correlations between perceived group discrimination and activation in perigenual ACC (PFWE = .001, region of interest corrected) and ventral striatum (PFWE = .02, whole brain corrected) and mediation of the relationship between perceived discrimination and perigenual ACC–dorsal ACC connectivity by chronic stress (P < .05).
Conclusions and Relevance Epidemiologists proposed a causal role of social-evaluative stress, but the neural processes that could mediate this susceptibility effect were unknown. Our data demonstrate the potential of investigating associations from epidemiology with neuroimaging, suggest brain effects of social marginalization, and highlight a neural system in which environmental and genetic risk factors for mental illness may converge.
The Social Brain, Stress, and Psychopathology (JAMA Psychiatry Editorial)
From the editorial:
“Social discrimination can have pervasive effects on human health and performance. This notion is a major thread binding together findings in social psychology, health psychology, and epidemiology. From a psychiatric perspective, it may also be critical for a more complete etiological picture of psychopathology. Social influences can be subtle but powerful. For example, priming racial identity can influence physiological measures of threat and performance on benchmark tests like the Scholastic Aptitude Test. As emphasized in the article by Akdeniz et al, ethnic minority immigrants are at greater risk than their native counterparts for schizophrenia, and this risk may extend to other mental and physical health disorders. To fully understand, prevent, and treat schizophrenia and other brain disorders, we need to understand the relationships between social context, stress, and brain health that cut across diverse psychiatric and neurological conditions.”