The Prosocial Effects of 3,4-methylenedioxymethamphetamine (MDMA): Controlled Studies in Humans and Laboratory Animals

Philip Kamilar-Britt and Gillinder Bedi

Neuroscience & Biobehavioral Reviews, 2015, 57, 433–446.

doi:10.1016/j.neubiorev.2015.08.016

 

Abstract

Users of ±3,4-Methylenedioxymethamphetamine (MDMA; ‘ecstasy’) report prosocial effects such as sociability and empathy. Supporting these apparently unique social effects, data from controlled laboratory studies indicate that MDMA alters social feelings, information processing, and behavior in humans, and social behavior in rodents. Here, we review this growing body of evidence. In rodents, MDMA increases passive prosocial behavior (adjacent lying) and social reward while decreasing aggression, effects that may involve serotonin 1A receptor mediated oxytocin release interacting with vasopressin receptor 1A. In humans, MDMA increases plasma oxytocin and produces feelings of social affiliation. It decreases identification of negative facial expressions (cognitive empathy) and blunts responses to social rejection, while enhancing responses to others’ positive emotions (emotional empathy) and increasing social approach. Thus, consistent with drug folklore, laboratory administration of MDMA robustly alters social processing in humans and increases social approach in humans and animals. Effects are consistent with increased sociability, with mixed evidence about enhanced empathy. These neurobiologically-complex prosocial effects likely motivate recreational ecstasy use.

Keywords : MDMA; ecstasy; molly; sociability; prosocial; social reward; social threat; empathy

 

1. Introduction

±3,4-methylenedioxymethamphetamine (MDMA) is the main psychoactive substance in the street drug known as ecstasy (in pill form) or, in the more recently emerging powder form, ‘molly’ (Duterte et al., 2009; Kahn et al., 2012). In 2012, ecstasy was estimated to be the 3rd most commonly used recreational drug among adults between the ages of 18 and 25 in the US (SAMHSA, 2013). Although use appeared to be declining in the early 2000s, there are indications of a re-emergence in popularity of this drug, with an estimated 869,000 first time users in the US in 2012 (SAMHSA, 2013). In addition to recreational use, MDMA is under investigation as a potential adjunct to psychotherapy for conditions such as Post Traumatic Stress Disorder (PTSD; Mithoefer et al., 2011; Mithoefer et al., 2013).

Although many recreational drugs are believed to alter social experiences (e.g. ‘beer goggles’, whereby alcohol is said to make potential romantic partners appear more attractive; Attwood et al., 2012), MDMA is, in popular culture, the prototypical social drug. Reflecting the belief that MDMA enhances empathy, classifying it under a novel drug class, ‘empathogens’, has been proposed (see Hysek et al., 2014a; Nichols et al., 1993). Language associated with MDMA use, such as the ‘love drug’ (Holland, 2001) and ‘cuddle puddle’ (a group of people cuddling while under the influence of ecstasy; Leneghan, 2013) further reflects popular perceptions of the drug’s apparent prosocial effects. Critically, these effects appear to motivate recreational ecstasy use (Morgan et al., 2013; Sumnall et al., 2006), suggesting that they contribute to the reinforcing properties of MDMA. Moreover, putative socio-emotional effects are argued to underlie the rationale for adjunctive MDMA use in psychotherapy (Johansen and Krebs, 2009; Oehen et al., 2013). Scientifically characterizing these effects is, thus, an important component of understanding both motivations for recreational MDMA use and possible mechanisms of any therapeutic effects. Research on prosocial effects of MDMA and their neurobiological substrates may also reciprocally inform understanding of the neurobiology of social behavior.

Over the past decade a rich body of research has emerged documenting alterations to social behavior in animals, as well as social feelings, information processing, and behavior in humans after controlled administration of MDMA. Here, we provide a systematic overview of these studies. Our aim is to elucidate the nature of identified social changes as well as their potential neurobiological mechanisms. We discuss implications of these findings in relation to recreational ecstasy/molly use and possible psychotherapeutic effects. Finally, we discuss important questions yet to be studied.

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