The precise nature and etiopathogenesis of borderline personality disorder (BPD) continues to elude researchers and clinicians. Yet, increasing evidence from various strands of research converges to suggest that affect dysregulation, impulsivity, and unstable relationships constitute the core features of BPD. Over the last two decades, the mentalizationbased approach to BPD has attempted to provide a theoretically consistent way of conceptualizing the interrelationship between these core features of BPD, with the aim of providing clinicians with a conceptually sound and empirically supported approach to BPD and its treatment. This paper presents an extended version of this approach to BPD based on recently accumulated data. In particular, we suggest that the core features of BPD reflect impairments in different facets of mentalization, each related to impairments in relatively distinct neural circuits underlying these facets. Hence, we provide a comprehensive account of BPD by showing how its core features are related to each other in theoretically meaningful ways. More specifically, we argue that BPD is primarily associated with a low threshold for the activation of the attachment system and deactivation of controlled mentalization, linked to impairments in the ability to differentiate mental states of self and other, which lead to hypersensitivity and increased susceptibility to contagion by other people's mental states, and poor integration of cognitive and affective aspects of mentalization. The combination of these impairments may explain BPD patients' propensity for vicious interpersonal cycles, and their high levels of affect dysregulation and impulsivity. Finally, the implications of this expanded mentalization-based approach to BPD for mentalization-based treatment and treatment of BPD more generally are discussed.

Reflective functioning or mentalizing is the capacity to interpret both the self and others in terms of internal mental states such as feelings, wishes, goals, desires, and attitudes. This paper is part of a series of papers outlining the development and psychometric features of a new self-report measure, the Reflective Functioning Questionnaire (RFQ), designed to provide an easy to administer self-report measure of mentalizing. We describe the development and initial validation of the RFQ in three studies. Study 1 focuses on the development of the RFQ, its factor structure and construct validity in a sample of patients with Borderline Personality Disorder (BPD) and Eating Disorder (ED) (n = 108) and normal controls (n = 295). Study 2 aims to replicate these findings in a fresh sample of 129 patients with personality disorder and 281 normal controls. Study 3 addresses the relationship between the RFQ, parental reflective functioning and infant attachment status as assessed with the Strange Situation Procedure (SSP) in a sample of 136 community mothers and their infants. In both Study 1 and 2, confirmatory factor analyses yielded two factors assessing Certainty (RFQ_C) and Uncertainty (RFQ_U) about the mental states of self and others. These two factors were relatively distinct, invariant across clinical and non-clinical samples, had satisfactory internal consistency and test–retest stability, and were largely unrelated to demographic features. The scales discriminated between patients and controls, and were significantly and in theoretically predicted ways correlated with measures of empathy, mindfulness and perspective-taking, and with both self-reported and clinician-reported measures of borderline personality features and other indices of maladaptive personality functioning. Furthermore, the RFQ scales were associated with levels of parental reflective functioning, which in turn predicted infant attachment status in the SSP. Overall, this study lends preliminary support for the RFQ as a screening measure of reflective functioning. Further research is needed, however, to investigate in more detail the psychometric qualities of the RFQ.

This paper reports on three studies on the development and validation of the Parental Reflective Functioning Questionnaire (PRFQ), a brief, multidimensional self-report measure that assesses parental reflective functioning or mentalizing, that is, the capacity to treat the infant as a psychological agent. Study 1 investigated the factor structure, reliability, and relationships of the PRFQ with demographic features, symptomatic distress, attachment dimensions, and emotional availability in a socially diverse sample of 299 mothers of a child aged 0–3. In Study 2, the factorial invariance of the PRFQ in mothers and fathers was investigated in a sample of 153 first-time parents, and relationships with demographic features, symptomatic distress, attachment dimensions, and parenting stress were investigated. Study 3 investigated the relationship between the PRFQ and infant attachment classification as assessed with the Strange Situation Procedure (SSP) in a sample of 136 community mothers and their infants. Exploratory and confirmatory factor analyses suggested three theoretically consistent factors assessing pre-mentalizing modes, certainty about the mental states of the infant, and interest and curiosity in the mental states of the infant. These factors were generally related in theoretically expected ways to parental attachment dimensions, emotional availability, parenting stress, and infant attachment status in the SSP. Yet, at the same time, more research on the PRFQ is needed to further establish its reliability and validity.

Mentalizing is the capacity to understand others and oneself in terms of internal mental states. It is assumed to be underpinned by four dimensions: automatic–controlled, internally–externally focused, self–other, and cognitive–affective. Research suggests that mental disorders are associated with different imbalances in these dimensions. Addressing the quality of mentalizing as part of psychosocial treatments may benefit individuals with various mental disorders. We suggest that mentalizing is a helpful transtheoretical and transdiagnostic concept to explain vulnerability to psychopathology and its treatment. This review summarizes the mentalizing approach to psychopathology from a developmental socioecological evolutionary perspective. We then focus on the application of the mentalizing approach to personality disorders, and we review studies that have extended this approach to other types of psychopathology, including depression, anxiety, and eating disorders. We summarize core principles of mentalization-based treatments and preventive interventions and the evidence for their effectiveness. We conclude with recommendations for future research.