Exploring nonverbal synchrony in borderline personality disorder: A double‐blind placebo‐controlled study using oxytocin

$\bf Objectives$ Interpersonal dysfunction is a central feature of borderline personality disorder (BPD), and the neuropeptide oxytocin (OT) has been shown to impact patients’ behaviour in numerous ways. Nonverbal signals such as the coordination of body movement (nonverbal synchrony) are associated with the success of interpersonal exchanges and could thus be influenced by features of BPD and by the administration of OT. $\bf Design$ We explored the effect of intranasal OT (inOT) on nonverbal synchrony in sixteen patients with BPD and fifteen healthy controls (CTL) randomly assigned to two double‐blind clinical interviews under inOT and placebo (PL). $\bf Methods$ Nonverbal synchrony was assessed by automated video‐analyses of subject’s and interviewer’s body movement. Lagged cross‐correlations were used to objectively quantify coordination in dyads. $\bf Results$ Synchrony was higher than pseudosynchrony (= synchrony expected by chance), and there was a differential effect of inOT between groups: While healthy controls displayed increased synchrony under inOT, patients with BPD showed low levels of synchrony under inOT. Additionally, patient’s synchrony was negatively associated with self‐reported childhood trauma. $\bf Conclusions$ Nonverbal synchrony in clinical interviews is influenced by inOT, and this effect depends on subject’s diagnosis. In line with previous research implying positive associations between nonverbal synchrony and relationship quality, inOT led to an increase of synchrony in healthy controls, but not in patients with BPD. Low levels of synchrony under inOT in patients and its association with childhood trauma suggest that additional mechanisms such as rejection sensitivity might mediate BPD patients’ nonverbal behaviour. $\textbf {Practitioner points}$ - Intranasal oxytocin (inOT) attenuated nonverbal synchrony – a proxy for relationship quality – in patients with borderline personality disorder (BPD), while it increased nonverbal synchrony in healthy controls (CTL). - Available models (rejection sensitivity; social salience) suggest that inOT may alter the way patients with BPD assess social situations, and this alteration is expressed by changes in nonverbal coordination. Patients with BPD display low levels of synchrony which are even below expected pseudosynchrony based on chance. -The association between self‐reported childhood trauma and lower synchrony in BPD was most evident for patient’s imitative behaviour: Under inOT, patients with high scores of childhood trauma refrained from imitating their interview partners. - Study limitations include small sample sizes and limited data on the psychological impact of the clinical interviews

Alterations of monetary reward and punishment processing in chronic cannabis users

Alterations in reward and punishment processing have been reported in adults suffering from long-term cannabis use. However, previous findings regarding the chronic effects of cannabis on reward and punishment processing have been inconsistent. In the present study, we used functional magnetic resonance imaging (fMRI) to reveal the neural correlates of reward and punishment processing in long-term cannabis users ($\it n$ = 15) and in healthy control subjects ($\it n$ = 15) with no history of drug abuse. For this purpose, we used the well-established Monetary Incentive Delay (MID) task, a reliable experimental paradigm that allows the differentiation between anticipatory and consummatory aspects of reward and punishment processing. Regarding the gain anticipation period, no significant group differences were observed. In the left caudate and the left inferior frontal gyrus, cannabis users were – in contrast to healthy controls – not able to differentiate between the conditions feedback of reward and control. In addition, cannabis users showed stronger activations in the left caudate and the bilateral inferior frontal gyrus following feedback of no punishment as compared to healthy controls. We interpreted these deficits in dorsal striatal functioning as altered stimulus-reward or action-contingent learning in cannabis users. In addition, the enhanced lateral prefrontal activation in cannabis users that is related to non-punishing feedback may reflect a deficit in emotion regulation or cognitive reappraisal in these subjects