Naltrexone Alters Responses to Social and Physical Warmth: Implications for Social Bonding

Tristen K. Inagaki; Laura I. Hazlett; Carmen Andreescu


Soc Cogn Affect Neurosci. 2019;14(5):471-479. 

In This Article

Abstract and Introduction


Socially warm experiences, when one feels connected to others, have been linked with physical warmth. Opioids, hypothesized to support social bonding with close others and, separately, physical warmth, may underlie both experiences. In order to test this hypothesis, 80 participants were randomly assigned to the opioid antagonist, naltrexone or placebo before neural and emotional responses to social and physical warmth were collected. Social and physical warmth led to similar increases in ventral striatum (VS) and middle-insula (MI) activity. Further, feelings of social connection were positively related to neural activity to social warmth. However, naltrexone (vs placebo) disrupted these effects by (i) reducing VS and MI activity to social and physical warmth, (ii) erasing the subjective experience–brain association to social warmth and (iii) disrupting the neural overlap between social and physical warmth. Results provide additional support for the theory that social and physical warmth share neurobiological, opioid receptor-dependent mechanisms and suggest multiple routes by which social connections may be maintained.


Close social connections and the feelings that come from being connected to other individuals are of utmost importance. Decades of research confirms that humans need close social connections to grow and thrive (Bowlby, 1988; Leary and Baumeister, 1995; Holt-Lunstad et al., 2010). However, relative to its suggested importance, feelings of social connection with our closest loved ones and the neurochemical, neural and psychological mechanisms that support such feelings are poorly understood. Therefore, we examine in the current study the causal role of opioids in feelings of social connection, neural activity to an experience of social connection and the potential overlapping contribution of physical warmth to social connection.