Neuronal effects of glabellar botulinum toxin injections using a valenced inhibition task in borderline personality disorder.

Previous studies have indicated that glabellar botulinum toxin (BTX) injections may lead to a sustained alleviation of depression. This may be accomplished by the disruption of a facial feedback loop, which potentially mitigates the experience of negative emotions. Accordingly, glabellar BTX injection can attenuate amygdala activity in response to emotional stimuli. A prototypic condition with an excess of negative emotionality and impulsivity accompanied by elevated amygdala reactivity to emotional stimuli is borderline personality disorder (BPD). In order to improve the understanding of how glabellar BTX may affect the processing of emotional stimuli and impulsivity, we conducted a functional magnetic resonance imaging (fMRI) study. Our hypotheses were (1) glabellar BTX leads to increased activation in prefrontal areas during inhibition performance and (2) BTX decreases amygdala activity during the processing of emotional stimuli in general. Using an emotional go-/no-go paradigm during fMRI, the interference of emotion processing and impulsivity in a sample of n = 45 women with BPD was assessed. Subjects were randomly assigned to BTX treatment or serial acupuncture (ACU) of the head. After 4 weeks, both treatments led to a reduction in the symptoms of BPD. However, BTX treatment was specifically associated with improved inhibition performance and increased activity in the motor cortex. In addition, the processing of negative emotional faces was accompanied by a reduction in right amygdala activity. This study provides the first evidence that glabellar BTX injections may modify central neurobiological and behavioural aspects of BPD. Since the control treatment produced similar clinical effects, these neurobiological findings may be specific to BTX and not a general correlate of symptomatic improvement.

Clinical effects of glabellar botulinum toxin injections on borderline personality disorder: A randomized controlled trial.

BACKGROUND: Inhibition of frowning via injections of botulinum toxin A (BTX) into the glabellar region has shown beneficial effects in the treatment of major depression. Preliminary research suggests that improvements in the affective domain are not depression-specific, but may also translate to other psychiatric disorders. AIM: This 16-week, single-blind, two-center randomized controlled trial investigated the influence of BTX on clinical symptoms of borderline personality disorder (BPD). METHODS: Fifty-four patients with BPD were randomly assigned to treatment with BTX (n = 27) or a minimal acupuncture (ACU) control condition (n = 27). Clinical outcomes were followed at 2, 4, 6, 8, 12, and 16 weeks. Primary endpoint was the relative score change on the Zanarini Rating Scale for Borderline Personality Disorder (ZAN-BPD) 8 weeks after baseline relative to the control group and adjusted for treatment center. Secondary and additional outcome variables were self-rated borderline symptoms, comorbid symptoms of depression, psychological distress, and clinical global impression. RESULTS: Participants showed significant improvements at the primary efficacy endpoint in both treatment groups (BTX: M = -0.39, SD = 0.39; ACU: M = -0.35, SD = 0.42), but no superior effect of the BTX condition in comparison with the control intervention was found-F(1,5323) = 0.017, p = 0.68). None of the secondary or additional outcomes yielded significant group differences. Side effects were mild and included headache, transient skin or muscle irritations, and dizziness. CONCLUSION: Evidence regarding the efficacy of BTX for BDP remains limited, and the design of adequate control conditions presents an opportunity for further research.ClinicalTrials.gov registry: Botulinum Toxin A for Emotional Stabilization in Borderline Personality Disorder (BPD), NCT02728778, https://clinicaltrials.gov/ct2/show/NCT02728778.