The longitudinal relationship between borderline personality features, disordered eating behaviour, and the role of impulsivity were examined using a sample of 643 Canadian adolescents from the McMaster Teen Study. Participants were assessed annually, beginning in Grade 7 until Grade 12.Using path analysis, the results suggest that higher symptoms of impulsivity increase an adolescent’s risk of engaging in disordered eating behaviour, as well as developing borderline personality features in later years. Results also showed a bidirectional relationship between these variables, whereby borderline personality features and disordered eating influence one another throughout time. As well, disordered eating appeared as an antecedent for borderline personality features. The findings highlight the importance for clinicians to be aware of the high comorbidity of disordered eating, borderline personality features, and impulsivity, and that early interventions that target impulsivity and problematic eating behaviour may mitigate the risk of future borderline personality features. Clinical implications, limitations, and future directions are discussed.

Individuals with borderline personality disorder (BPD) experience severe and pervasive disturbances in the development of attachment relationships, identity, and emotion regulation. Given these deficits, mothers diagnosed with BPD are likely to experience significant difficulties in parenting their children. The present study examined the effect of maternal BPD and borderline personality features on emotional availability in interactions between mothers with BPD and their 4- to 7-year-old children. In a low socioeconomic status (SES) sample of n = 35 children of mothers diagnosed with BPD and n = 35 normative comparisons, groups were compared on maternal and child emotional availability, and self-reported maternal borderline personality features were assessed across the sample as a whole. No significant differences in emotional availability were found between groups. Across the sample as whole, however, maternal borderline personality features of affective instability, identity disturbance, negative relationships, and self-harm were significantly correlated with maternal intrusiveness and maternal hostility. Maternal borderline personality features of affective instability and negative relationships were significantly associated with maternal sensitivity, child responsiveness, and child involvement. Results are discussed in terms of putative precursors to BPD and preventive interventions.

Introduction: Borderline personality disorder (BPD) is a severe psychiatric disorder characterized by emotion dysregulation, interpersonal dysfunction, and poor impulse control. Little research has investigated BPD in the context of major life events. The perinatal period (pregnancy until 12 months postpartum) is an important milestone that involves major role transitions and novel challenges. This thesis examined the associations between borderline personality features (BPF) and depressive and generalized anxiety symptoms in a sample of treatment-seeking perinatal women. Methods: 74 perinatal women were recruited from the Women’s Health Concerns Clinic (WHCC) at St. Joseph’s Healthcare Hamilton, Canada, and enrolled in the WHCC Registry study. Participants were sent online intake questionnaires to collect data about demographic, personality, and other psychosocial variables. They also completed three self-report mental health measures: the McLean Screening Instrument for Borderline Personality Disorder (MSI-BPD), the Edinburgh Postnatal Depression Scale (EPDS), and the Generalized Anxiety Disorder Scale (GAD-7). Logistic regression was used to determine whether a positive MSI-BPD screen (score ≥ 7) was associated with a higher likelihood of screening positive on the EPDS or GAD-7 (score ≥ 13). Results: A positive screen on the MSI-BPD was significantly associated with an almost eighteen-fold increase in the odds of screening positive on the EPDS in our treatment-seeking perinatal sample (OR 17.84, 95% CI[2.11, 218.80], p<0.05). A positive screen on the MSI-BPD was not associated with higher odds of screening positive on the GAD-7, rather only childhood trauma and a positive screen on the EPDS emerged as significant predictor variables. Our findings may reflect the greater symptomatic overlap observed between BPD and perinatal depression as well as the comparatively lower comorbidity observed between GAD and BPD in non-perinatal research. Conclusions and Future Directions: The use of self-report measures, low statistical power, and a treatment-seeking sample are limitations to consider when interpreting our findings. To our knowledge, this research study offers one of the first explorations into the relationship between BPD and generalized anxiety symptoms during the perinatal period. Future research should aim to better characterize perinatal BPD and investigate its relationship with other mental health conditions. / Thesis / Master of Science (MSc) / The perinatal period (pregnancy until 12 months postpartum) represents a time of heightened vulnerability to poor mental health. Prior research has mainly focused on perinatal depression and anxiety, while perinatal personality disorders have received comparably less attention. Borderline personality disorder (BPD) is a severe psychiatric disorder associated with diminished ability to regulate emotions, disturbances in self-image, troubled interpersonal relationships, and impulsive behaviour. This thesis investigated the relationship between self-reported borderline personality features (BPF) and depressive and generalized anxiety symptoms in a sample of perinatal women seeking treatment at a psychiatric clinic. We hope that this research sheds light on the nature of perinatal BPD, as well as its associations with other mental health conditions, to improve both immediate and multi-generational maternal and infant well-being.