Opioid Function Is Dysregulated Subsequent to Early Social Trauma: Healthy Young Adults’ Response to a Buprenorphine Challenge

Panksepp’s separation-distress model of depression posits that endogenous opioid systems become dysregulated subsequent to early social trauma and that this dysregulation constitutes a risk factor for depression. We tested an aspect of this model by recruiting medically and psychiatrically healthy young adults (N = 32) who differed on one key criterion—exposure to early social trauma. In terms of core affective personality traits as measured by the Affective Neuroscience Personality Scales (ANPS), those not exposed to early social trauma scored significantly higher on SEEKING; the groups did not differ on SADNESS. Importantly, the groups also responded differently to a low-dose opioid challenge (0.2 mg sublingual buprenorphine vs. placebo). Buprenorphine administration had little effect on emotion in controls, but it reduced experience of both positive and negative emotion in trauma-exposed participants. The latter also showed a significant negative bias in social cognition that was not attenuated by buprenorphine, whereas controls were more likely to show a positive bias on buprenorphine (relative to trauma-exposed participants). The groups’ differing responses to buprenorphine suggest that their opioid systems are functioning differently. These data constitute preliminary proof of concept for a key aspect of the model. Further investigation of the role of endogenous opioids in depression subsequent to early social trauma is warranted.