Effects of transcranial direct current stimulation on the cognitive control of negative stimuli in borderline personality disorder

Abstract

Borderline personality disorder (BPD) is characterized by impairments in the cognitive control of negative information. These impairments in cognitive control are presumably due to blunted activity of the dorsolateral prefrontal cortex (dlPFC) along with enhanced activations of the limbic system. However, the impact of an excitatory stimulation of the dlPFC still needs to be elucidated. In the present study, we therefore assigned 50 patients with BPD and 50 healthy controls to receive either anodal or sham stimulation of the right dlPFC in a double-blind, randomized, between-subjects design. Participants performed a delayed working memory task with a distracter period during which a grey background screen, or neutral, or negative stimuli were presented. This experimental paradigm was first evaluated in a pilot study with 18 patients with BPD and 19 healthy controls. In both studies, patients with BPD showed an impairment of cognitive control when negative distracters were presented in the delay period of a working memory task. However, excitatory stimulation of the right dlPFC did not ameliorate cognitive control of negative stimuli in BPD, which raises questions about the specific role of the right dlPFC for the understanding of BPD psychopathology. Methodological limitations are discussed.

Figure 1

Separate boxplots and individual results of response latencies for trials with negative distracters controlled for response latencies to neutral stimuli for patients with BPD and healthy controls.

Figure 2

Separate boxplots and individual results of response latencies for trials with negative distracters controlled for response latencies to neutral stimuli for patients with BPD and healthy controls. Individual results are presented separately for the stimulation condition. Please note, one participant had a value of 831 ms and is not presented in the figure. Findings remain significant when excluding this individual from data analysis.