Impulsivity has been shown to load on two separate factors, rash impulsivity and sensitivity to reward (SR) in several factor analytic studies. The aims of the current study were to explore the nature of impulsivity in women with borderline personality disorder (BPD) and matched controls, and the underlying neuronal correlates for rash impulsivity and SR.

Fifteen females diagnosed with BPD and 15 matched controls were recruited. All completed the impulsiveness-venturesomeness scale (I7), the sensitivity to punishment (SP) - sensitivity to reward (SR) questionnaire, and performed a Go-NoGo block-design functional magnetic resonance imaging (fMRI) paradigm at 3T. Correlation analyses were done with I7, SP and SR scores with the level of activation in different brain areas in the whole group. An independent group t-test was used to explore any differences between the BPD group and the matched controls.

I7 scores correlated negatively with activity in the left orbitofrontal cortex, amygdala and precuneus, and bilaterally in the cingulate cortices during response inhibition for the entire sample. SP yielded negative correlations in the right superior frontal gyrus and parahippocampal gyrus. No activity related to response inhibition correlated to SR. The Go-NoGo task gave similar brain activity in BPD and matched controls, but behaviourally the BPD group had significantly more commission errors in the NoGo blocks. The BPD group had increased I7 and SP scores indicating rash impulsiveness combined with heightened SP.

These results imply that successful impulse inhibition involves interaction between the impulsive and the emotional systems. Furthermore, impulsivity in BPD is described as rash impulsivity, coexisting with increased SP.