Social Homeostasis and Psychoactive Drugs: What Can We Learn From Opioid and Amphetamine Drug Challenge Studies in Humans?

Social disequilibrium, or disrupted social homeostasis, underlies many behavioral disorders, including problematic drug use. One way to study the relationship between drug use and social homeostasis is to determine whether single doses of psychoactive drugs relieve some of the discomfort of social isolation and promote social connection. In this narrative review, we discuss challenges and opportunities in studying the relationship between psychoactive drugs and social homeostasis. Using the examples of opioids and amphetamines, we discuss the evidence that drugs alleviate dysphoria related to lack of social connection or produce prosocial effects that improve connection. With regard to opioid drugs, we report that mu opioid agonists and kappa opioid antagonists reduce distress from social isolation, and mu opioid agonists enhance social reward. Amphetamine-like stimulant drugs, including MDMA, do not seem to act by reducing the distress of social isolation, but they have notable prosocial effects that increase both motivation for social contact and the pleasure derived from interacting socially. Many questions remain in understanding interactions between drugs and social equilibrium, including whether these effects contribute to problematic drug use. We identify gaps in knowledge, including the effects of drug withdrawal or dependence on social function or the responses of individuals with psychiatric symptomatology. Understanding these actions on social processes will help to develop novel pharmacological treatments for clinical problems related to social disequilibrium.