According to the American Psychiatric Association (2013), personality disorders refer to a rigid and persistent set of behaviours that deviates from societal and cultural standards, thus, resulting in dysphoria and impairments in affective, cognitive, or social domains. One common personality disorder is Borderline Personality Disorder (BPD; Cullen et al., 2011). Hallmark characteristics of BPD, as stated in the Diagnostic and Statistical Manual of Mental Disorders (DSM; American Psychiatric Association, 2013), include extreme apprehension of abandonment, loneliness, and socially unacceptable behaviour that jeopardise interpersonal relationships. Individuals with BPD also idealize (i.e. have high regards for) and devalue (i.e. high displeasure for) others. Next, emotional lability (i.e. the inability to control extreme mood changes) is also common in BPD (Ruocco, Medaglia, Ayaz, & Chute, 2010). Another common manifestation in BPD is impulsive tendencies to engage in self-detrimental actions such as suicidal ideation and acts, drug or alcohol indulgence, or unprotected sex (Nunes et al., 2009; Perez et al., 2016; Rossi et al., 2013). Individuals with BPD exhibit an inordinate amount of anger in response to stimuli, regardless of whether it is a neutral or anger-provoking situation (Brunner et al., 2010).
The epidemiology of BPD comprises of factors such as neurochemistry (i.e. serotonin and dopamine; Gurvits, Koenigsberg, & Siever, 2000), environmental factors (i.e. traumatic childhood experiences, sexual abuse, or neglect), and brain abnormalities (i.e. increased or decreased activation, or reduced volume; American Psychiatric Association, 2013). For this study, only brain abnormalities associated to BPD will be discussed.
Myriad of studies highlight the involvement of the prefrontal cortex and fronto-limbic system in BPD (Rossi et al., 2013). According to Juengling et al. (2003), the fronto-limbic system includes the orbitofrontal cortex (OFC), prefrontal cortex (PFC), amygdala, anterior cingulate cortex (ACC), and hippocampus. As discussed below, any impairment or dysfunction in these areas bring about several characteristics of BPD such as emotional lability, hostility, and recklessness (Brunner et al., 2010; New et al., 2007; Rossi et al., 2013). However, impairment in these regions have also been detected in other comorbidities that manifest with BPD (American Psychiatric Association, 2013). This indicates that it is difficult to discern whether damage to these regions are BPD-specific or due to other comorbid disorders (Nunes et al., 2009). Hence, this study explores brain abnormalities observed in BPD subjects.