The endogenous opiate system (EOS) has been linked to social attachment in classical animal experiments, to addictive disorders (AD) and, more recently, to specific traits of personality through research in genetic polymorphisms and neuroimaging techniques.

To expose the relation between social bonding and AD, via the latest neurobiological findings in the EOS. To propose a theoretical framework which may allow a clinical approach based upon respect and no stigmatization.

Literature review in MEDLINE database with the keywords “opioid”, “polymorphism”, “object attachment”, “addictive behavior”, “personality”.

Polymorphisms in the mu-opioid receptor gene lead to different attachment behaviors in primates. The EOS in humans has been related to pain and placebo effect and recently, to social rejection and acceptance. Thus, some authors talk about “social pain”. Interestingly, the EOS has a role in harm avoidance and in the reward system. These traits of personality (harm avoidance and reward dependence) predispose to AD, and likely, pathological models of social bonding may drive to a need of palliating excessive discomfort originated by an altered opioid function through addictive behaviors. The origin of AD must be focused on the individual vulnerability rather than in the addictive substance/behavior.

The latest findings in the EOS yield concrete evidences that support the classical hypothesis of an opioid nexus between social attachment and AD, and shift the spotlight from the addictive object to the vulnerable subject. This theoretical framework may ease a clinical approach based upon respect and no stigmatization.

The authors have not supplied their declaration of competing interest.