Negative emotions weaken the error monitoring ability of patients with borderline personality disorder.

Patients with Borderline Personality Disorder (BPD) exhibit impaired inhibitory control and heightened affective sensitivity. This study aimed to investigate how negative emotions influence error monitoring in BPD. Twenty-six BPD patients and twenty-eight health controls completed psychological scales assessing borderline symptoms, impulsivity, depression and anxiety. Subsequently, participants performed an emotional stop signal task while electroencephalogram (EEG) data were collected. Error-related neural activity was analyzed, focusing on the amplitude of error-related negativity (ERN), error positivity (Pe), and power values of error-related θ. Repeated measures analysis of variance (ANOVA) assessed differences by group and emotion type. Pearson correlations were calculated between error-related EEG variables and psychological scales. Results revealed significant group-by-emotion type interactions for ERN amplitude (F = 27.094, p < 0.001, η²_p = 0.387) and θ power (F = 4.121, p = 0.049, η²_p = 0.093). Specifically, under negative emotional conditions, BPD patients exhibited significantly lower ERN amplitudes and θ power than controls, while no significant group differences were found under neutral conditions. ERN amplitude at FZ under negative emotion conditions correlated significantly with non-planning impulsivity (r = 0.466). Moreover, θ power under neutral conditions correlated significantly with borderline symptoms and impulsive behaviors (r = 0.447 to 0.612). In conclusion, BPD patients demonstrate notable deficits in error detection during negative emotion states, impairing their ability to correct errors and adjust behaviors. The results provide valuable insights for clinical intervention of impulsive behaviors in BPD, as such behaviors can be reduced by guiding patients to attend to the consequences of impulsive behaviors in negative emotional states.