Emotion avoidance and fear bradycardia in patients with borderline personality disorder and healthy controls

QTc dispersion and interval changes in drug-free borderline personality disorder adolescents

Emotional instability and dysregulation represent a core feature of borderline personality disorder (BPD) and abnormal patterns of sympathetic/parasympathetic activity have been repeatedly investigated in individuals with this disorder. Such abnormalities may represent the substrate for an arrhythmogenic risk that could materialize the following specific drug exposure. In this work, we decided to assess basal-corrected QT interval and dispersion (QTc and QTcd) for estimating such risk in a sample of drug-free adolescents with diagnosis of BPD. In this cross-sectional comparative study, we recruited n = 70 female adolescent BPD (14.7 ± 1.3 years), free of medications, alcohol or recreational drugs. Furthermore, n = 70 matched female healthy controls (CTRL, 14.6 ± 1.5 years) were enrolled. QTc and QTcd were manually assessed on a standard 12-lead ECG by a single experienced investigator who was unaware of clinical outcomes. QTcd was increased by 7 ms on average in BPD vs. CTRL (+ 18%, p = 0.03). QTc was decreased by about 15 ms on average in BPD vs. CTRL (p = 0.003). A mild correlation was found between QTc and QTcd in BPD (r = 0.25, p = 0.03) that was not present in CTRL. No correlation was found between either QTc or QTcd, and age in both groups. Mildly increased QTcd characterizes the cardiac activity regardless of drug exposure in female adolescents with BPD. This information may be of value to clinicians striving to use neuroleptic and antidepressant drugs with a lower risk of QTcd increase.

Freezing in response to social threat: a replication

Freezing is an adaptive defensive response to a stressful event. Recent research suggests that freezing not only occurs in response to physical threats but also in response to social threats (e.g., angry faces; Roelofs et al. in Psychol Sci 21:1575-1581, 2010). Given the practical and theoretical importance of this finding, the current study aimed to replicate and extend it. Following the original study, we measured heart rate while participants viewed emotional faces (angry, happy, neutral). Extending the original study, we included a baseline measure and performed additional, more fine-grained analyses. Our results support the hypothesis that participants show physiological signs of freezing when looking at angry faces. Importantly, we also find this effect when comparing heart rate in the angry block to baseline levels. Interestingly, the heart rate effects are explained by deceleration in the first 30 s of the 1-min angry block, but not in the second 30 s. Like Roelofs et al., we find evidence that the effects are modulated by state anxiety, but our effects are only marginal and we do not replicate the negative correlation between heart rate and state anxiety in the angry block. In general, we thus find evidence for physiological signs of freezing in response to social threat. We discuss implications and venues for future research.

Incident experience predicts freezing-like responses in firefighters

Freezing is a defensive response to acute stress that is associated with coping and alterations in attentional processing. However, it remains unclear whether individuals in high risk professions, who are skilled at making rapid decisions in emergency situations, show altered threat-induced freezing. Here we investigated the effect of incident experience in a high risk profession on freezing. Additionally, we explored whether any effect of incident experience on freezing would be different for profession-related and -unrelated threat. Forty experienced and inexperienced firefighters were presented neutral, pleasant, related-unpleasant, and unrelated-unpleasant pictures in a passive viewing task. Postural sway and heart rate were assessed to determine freezing. Both postural and heart rate data evidenced reduced freezing upon unpleasant pictures in the experienced versus the inexperienced group. Relatedness of the unpleasant pictures did not modulate these effects. These findings indicate that higher incident experience relates to decreased threat-induced freezing, at least in a passive task context. This might suggest that primary defense responses are malleable through experience. Finally, these findings demonstrate the potential of using animal to human translational approaches to investigate defensive behaviors in relation to incident experience in high risk professions and stimulate future research on the role of freezing in resilience and coping.

Reduced Freezing in Posttraumatic Stress Disorder Patients while Watching Affective Pictures

Besides fight and flight responses, animals and humans may respond to threat with freezing, a response characterized by bradycardia and physical immobility. Risk assessment is proposed to be enhanced during freezing to promote optimal decision making. Indeed, healthy participants showed freezing-like responses to threat cues. Posttraumatic stress disorder (PTSD) patients are characterized by hypervigilance and increased threat responsiveness. We propose that threat responses will be characterized by decreased freezing in PTSD, eliminating possibilities for rejecting cognitive distortions, such as harm expectancy, and thereby contributing to the maintenance of the disorder. However, freezing responses have hardly been investigated in PTSD. Using a stabilometric platform to assess body sway as an indicator of freezing-like behavior, we examined whether veterans with PTSD would show diminished freezing responses to unpleasant versus neutral and pleasant pictures. Fourteen PTSD patients and 14 healthy matched controls watched the pictures, while body sway and heart rate (HR) were continuously assessed. Replicating previous findings, healthy controls showed decreased body sway and HR in response to unpleasant pictures, indicative of freezing-like behavior. In contrast, this response pattern was not observed in PTSD patients. The results may indicate a reduced freezing response in PTSD. As reduced freezing may hinder appropriate risk assessment, it may be an important factor in the maintenance of PTSD. Future research might clarify whether impaired freezing is a PTSD-specific or a transdiagnostic symptom, being present in threat-related disorders.