تمایز خطر برای اختلال شخصیت مرزی و شیدایی: ماهیت مقررات هدف و تکانشگری

Researchers and clinicians have long noted the overlap among features and high comorbidity of bipolar disorder and borderline personality disorder. The shared features of impulsivity and labile mood in both disorders make them challenging to distinguish. We tested the hypothesis that variables related to goal dysregulation would be uniquely related to risk for mania, while emotion-relevant impulsivity would be related to risk for both disorders. We administered a broad range of measures related to goal regulation traits and impulsivity to 214 undergraduates. Findings confirmed that risk for mania, but not for borderline personality disorder, was related to higher sensitivity to reward and intense pursuit of goals. In contrast, borderline personality disorder symptoms related more strongly than did mania risk with threat sensitivity and with impulsivity in the context of negative affect. Results highlight potential differences and commonalities in mania risk versus borderline personality disorder risk.

There has been ongoing debate as to whether borderline personality disorder and bipolar spectrum disorders—including bipolar I and II disorders and cyclothymia—are overlapping or distinct conditions (Stone, 2006 and Bassett, 2012). Across studies, as many as 14.5–30% of those with bipolar I disorder (Kay et al., 1999, Brieger et al., 2003 and Perugi et al., 2013), and as many of 46% of those with bipolar II disorder (Vieta and Colom, 1999, Benazzi, 2000 and Henry et al., 2001) also meet criteria for borderline personality disorder. Among respondents with borderline personality disorder in the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) study, 23.9% also met criteria for bipolar I disorder (Grant et al., 2008). In the community, misdiagnosis between these two conditions is all too common (Ruggero et al., 2010). The high degree of overlap suggests the possibility of shared risk and, consistent with this idea, both disorders involve affective instability and impulsivity (Magill, 2004). Indeed, some propose that both bipolar spectrum disorders and borderline personality disorder share the same underlying cyclothymic diathesis (Perugi et al., 2011). On the other hand, more than half of those with bipolar disorder do not appear to meet criteria for borderline personality disorder, suggesting that identifying unique facets of the two conditions could improve diagnostic accuracy (Blacker and Tsuang, 1992). In this paper, we focus on personality traits that could help explain overlap in risk for bipolar disorder and borderline personality disorder, as well as traits that might help distinguish risk for the two conditions. Before turning to a discussion of personality traits, it is worth reviewing how well the two conditions can be distinguished on the basis of symptoms, course, and treatment (Paris, 2004). Bipolar spectrum disorders are distinguished by propensities toward elation (Henry et al., 2001) and discrete episodes (Paris, 2004), and are more responsive to mood stabilizers (Paris, 2004). None of these characteristics, though, are fail proof. Many people with bipolar I disorder do not report elation during mania (Sato et al., 2002 and Akiskal et al., 2003). It is increasingly well-recognized that people with bipolar spectrum disorders experience chronic unremitting depressive symptoms (Judd et al., 2002), as well as affective instability outside of episodes (Akiskal, 2004), and many experience only a partial response to mood stabilizers (Bauer, 2005). Indeed, the overlap among symptoms has led some to argue for considering borderline personality disorder an “ultrarapid-cycling” variant of bipolar spectrum disorders (Deltito et al., 2001). Further adding to the difficulties in relying on symptoms and course for differential diagnosis, a growing body of research suggests that borderline personality symptoms frequently remit, even though functional impairments can be more persistent (Zanarini et al., 2003a and Gunderson et al., 2011). Symptoms, course, and treatment response may not always provide diagnostic clarification, then, given the heterogeneity in the expression of these disorders. Examining personality traits might help to bolster the ability to distinguish these two conditions. A growing literature has related bipolar spectrum disorders to goal dysregulation and emotion-relevant impulsivity. For example, multiple studies have found that sensitivity to reward is heightened among those at risk for mania—defined by elevated scores on the Hypomanic Personality Scale (HPS)—as well as among persons with remitted bipolar disorders (Alloy et al., 2009; see Johnson et al. (2012a) for review). Bipolar I disorder and risk for mania have been related to more intense pursuit of goals, including measures of goal striving (Spielberger et al., 1963, Scott et al., 2000, Lam et al., 2005, Wright et al., 2005, Alloy et al., 2008 and Fulford et al., 2009) and extremely ambitious life goals (Johnson and Carver, 2006, Fulford et al., 2008, Carver and Johnson, 2009, Gruber and Johnson, 2009 and Johnson and Jones, 2009), even after controlling for current mood symptoms. Risk for mania has also been related to greater cognitive reactivity to goal progress (i.e., “positive overgeneralization”; Eisner et al., 2008). Goal dysregulation has received less attention within borderline personality disorder. Here, we suggest that goal dysregulation may help distinguish those at risk for mania compared to those at risk for borderline personality disorder. In contrast, borderline personality disorder and bipolar disorder have both been related to impulsivity. Bipolar I disorder and risk for mania have been related to heightened impulsivity, especially during positive mood states (Swann et al., 2001 and Giovanelli et al., 2013; Johnson et al., 2013; Muhtadie et al., 2014 and Newman and Meyer, 2014), and this aspect of impulsivity can be observed even during well periods. Borderline personality disorder has long been related to impulsivity (Lieb et al., 2004), and more recent research suggests that specific elevations in emotion-relevant impulsivity are present as well. Similarly, previous research has suggested that both bipolar disorders and borderline personality disorder are related to an increased propensity towards urgency, or impulsivity during negative emotion states (Whiteside et al., 2005; Johnson et al., 2013; Muhtadie et al., 2014). In one study, individuals diagnosed with borderline personality disorder (and comorbid major depressive disorder) reported significantly more impulsivity than did individuals diagnosed with bipolar II disorder (Wilson et al., 2007). Beyond impulsivity, negative affectivity might be elevated in those at risk for borderline and bipolar disorders (Maples et al., 2014). Self-reported sensitivity to threat, as indexed by the Behavioral Inhibition Scale (BIS; Carver and White, 1994), is elevated among those with borderline personality traits (Pastor et al., 2007 and Claes et al., 2009) and diagnoses (Taylor et al., 2006 and Mortensen et al., 2010). Several studies have suggested that BIS is elevated only during periods of depression among those with bipolar spectrum disorders (see Johnson et al. (2012a) for review). In studies comparing levels of negative affectivity across diagnostic groups, individuals diagnosed with borderline personality disorder reported significantly more negative affectivity (hostility and depressed mood) than did individuals diagnosed with bipolar II disorder or cyclothymia (Wilson et al., 2007 and Reich et al., 2012). Caution is warranted in that the Wilson study focused on individuals with borderline personality disorder comorbid with major depressive disorder. In sum, although affective dysregulation is commonly noted in both bipolar spectrum disorders and borderline personality disorder, the relation of affect to goal regulation and impulsivity may provide insight into distinguishing risk for the two disorders. The aim of the current study was to understand how goal regulation, emotion-relevant impulsivity, and threat sensitivity might help differentiate risk for mania and borderline personality disorder. Based on findings from the above literature, we hypothesized that risk for both mania and borderline personality disorder would be associated with emotion-relevant impulsivity, while risk for mania would be more strongly associated with goal dysregulation than would risk for borderline personality disorder. We included several measures of goal regulation traits that have been previously found to relate to mania risk and bipolar disorder (including reward sensitivity, over-responsivity to goal progress, and ambitious goal-setting). In considering these issues, it is worth noting our methodological approach. Whereas studies of individuals with diagnosed bipolar disorders and borderline personality disorder undoubtedly have advantages, the repeated difficult experiences of these disorders can have significant implications for negative affect and goal regulation, and the treatments may influence negative affect as well as impulsivity (Newman and Meyer, 2014). As such, it is difficult to determine whether personality trait elevations observed within clinically diagnosed samples represent defining features of these disorders or byproducts of illness chronicity and treatment. In this study, then, we chose to study varying risk for bipolar and borderline personality disorders, rather than a clinical sample, by using scales that were designed to screen for risk of bipolar and borderline personality diagnoses.