A meta-analysis of theory of mind and 'mentalization' in borderline personality disorder: a true neuro-social-cognitive or meta-social-cognitive impairment?

BACKGROUND

It is widely accepted that borderline personality disorder (BPD) is associated with significant impairments in mentalization and theory of mind (ToM) which are considered as closely related concepts by many authors particularly in psychoanalytical circles. However, for understanding interpersonal difficulties in personality disorders, it is important to distinguish neuro-social cognitive impairment from the abnormal meta-social-cognitive style of patients.

METHODS

The current systematic review aimed to conduct separate meta-analyses of 'mentalization' [reflective functioning (RF] and different aspects of ToM in BPD. A literature search was conducted to locate relevant articles published between January 1990 to July 2021. Random-effect meta-analyses were conducted in 34 studies involving 1448 individuals with BPD and 2006 healthy controls.

RESULTS

A very large impairment in RF was evident in BPD [d = 1.68, confidence interval (CI) = 1.17-2.19]. In contrast, ToM impairment was modest (d = 0.36, CI = 0.24-0.48). BPD patients underperformed healthy controls in ToM-reasoning (d = 0.44, CI = 0.32-0.56) but not ToM-decoding. Increased HyperToM (d = 0.60, CI = 0.41-0.79) and faux pas recognition (d = 0.62, CI = 0.35-0.90) errors in BPD compared to healthy controls were most robust ToM findings in this meta-analysis.

CONCLUSIONS

BPD is characterized by very severe deficits in RF and modest and selective abnormalities in ToM. Interpersonal problems and difficulties in processing social information in BPD can be best explained by patients' maldaptive meta-social cognitive style and top-down effects of these abnormalities rather than having a primary neuro-social cognitive deficit.