Social isolation has been found to be as detrimental to health as smoking and obesity, but the neural mechanisms linking social relationships to health and well-being are poorly understood. Evidence suggests that social support may increase endogenous opioid activity throughout the brain, and opioids limit the brain's reaction to stress. The proposed research will utilize a pharmacological intervention--naltrexone--to block endogenous opioid activity during a procedure that combines social support and functional magnetic resonance imaging (fMRI). Using a randomized, double-blind placebo control design, participants will first receive either an opioid antagonist (which blocks the effects of opioids) or an inert sugar pill. Participants will then be subjected to a stressor during brain imaging under each of three conditions: while alone, while receiving social support from a stranger, and while receiving support from a spouse.
Dr. James Coan (University of Virgina) and colleagues' past research has demonstrated that threat-related brain activity is attenuated by social support using this experimental design, particularly when the support provider is a spouse. If opioid antagonists block this effect from occurring, that will constitute compelling evidence that at least one key mechanism linking social contact to better health is the activation of opioid activity that buffers us against the effects of stress. This study is unique in providing 1) a critical test of the opioid hypothesis of social support in humans; and 2) a novel approach to the methods used in this area of research by mixing a pharmaceutical intervention, a social support manipulation, and fMRI, all in a broadly representative community sample.
Historically, the greatest strides in understanding important phenomena follow a detailed account of underlying mechanisms. If naltrexone blocks the impact of social support on the brain's threat response, then vital steps will have been taken toward understanding the nature of well documented links between social relationships and health. Understanding these mechanisms could have a broad and meaningful influence on a numerous and diverse array of scientific and medical questions, paying substantial dividends to society as a whole. Knowledge of the basic mechanisms supporting relationship-health associations will help us to realize full potential of interventions that emphasize social relationships across a variety of disciplines and contexts.
