Cognitive correlates of borderline intellectual functioning in borderline personality disorder

Borderline intellectual functioning (BIF) is highly prevalent in patients with borderline personality disorder (BPD), but their relationship remains poorly understood. This retrospective study aimed to investigate the cognitive profile of BIF among people diagnosed with BPD. Clinical, demographic, and neuropsychological data of fifty-five outpatients with BPD were analyzed. The sample split into two groups: BPD with BIF (BIF+: n = 25; intelligence quotient - IQ - range: 71-84) and BPD without BIF (BIF-: n = 30; IQ range: 86-124). Between-group comparisons employed either parametric and non-parametric descriptive statistics, as necessary. Neuropsychological measures (Wechsler Adult Intelligence Scale-Revised - WAIS-R IQ, factor index, subtest scores) and cognitive performance deficits in the two groups were likewise compared aside, followed by Spearman's correlation test conducted on relevant metrics. The cognitive, but not the clinical and demographic profiles differed significantly between the two groups. BIF+ was associated with a specific pattern of verbal, attentive, and planning dysfunctions. The verbal comprehension index had the highest discriminative value for the presence of BIF in patients with BPD, and it was tightly associated with adaptive and social functioning. The neuropsychological assessment of BPD may be relevant to plan targeted interventions based on measures of cognitive functioning which could also serve to evaluate treatment efficacy and outcomes. Clinical implications and future directions are discussed.