Few studies to date have been performed to investigate impulsivity and aggressivity in patients with bipolar disorder (BD) and borderline personality disorder (BPD); the primary aim of the present study was to evaluate the impact of co-morbidity of BPD on impulsivity and aggressivity in patients affected by BD. A total of 57 patients (male = 20, female = 37) affected by BD (BD-I 51%; BD-II 49%) in clinical stable remission were recruited; 28 patients were affected by BD (49.1%), 18 by BD and BPD (31.6%) and 11 (19.3%) by BD plus other personality disorders (OPD) (19.3%). They were assessed with the Structured Clinical Interview for DSM-IV (SCID)-I and SCID-II, and were evaluated by means of the Clinical Global Impression (CGI)-severity and Global Assessment Functioning (GAF) scales, the Barratt Impulsivity Scale (BIS-11) and the Aggression Questionnaire (AQ). Mean total scores were significantly higher among BD/BPD patients with respect to BD and to BD/OPD, both on the BIS-11 and the AQ; the rate of attempted suicides was approximately three times higher in BD/BPD patients with respect to BD and 7.6 times higher than in BD/OPD patients. The results of our study suggest that patients with co-morbid BD and BPD are more impulsive and aggressive. Furthermore, this co-morbid condition may be a risk factor for suicidality.
Impulsivity is a common feature of several psychiatric disorders (Bellino et al., 2003) such as bipolar disorders (BDs) (Swann et al., 2001 and Swann et al., 2003) and cluster B personality disorders (Looper and Paris, 2000), in particular, borderline personality disorder (BPD) (Stone, 1990, Zanarini, 1993, Mehlum et al., 1994 and Links et al., 1999). Impulsivity seems to be one of the most stable characteristics of personality in borderline patients, while in bipolar subjects, both a state and a trait component may be recognised, both episodic and interepisodic impulsivity having been demonstrated (Moeller et al., 2001). Whether trait (interepisodic) impulsivity is a risk factor for bipolar disorder or a consequence of repeated episodes of illness is still controversial (Moeller et al., 2001). Aggressiveness is frequently manifested in different clinical conditions, including BDs (Latalova, 2009) and borderline and antisocial personality disorders (Lish et al., 1996 and Moeller et al., 2001). Hostility and aggression may be important as core features of manic and mixed states, independent of psychosis (Cassidy et al., 2002, Sato et al., 2002 and Maj et al., 2003). Aggression in bipolar disorder seems to be mostly impulsive and occurring not only during manic and mixed episodes, but also during remission (Latalova, 2009), but unresolved questions persist about the state- versus trait-dependent nature of aggression in BD (Garno et al., 2008). Cluster B personality disorders are associated with high levels of aggressiveness (Fossati et al., 2007), and impulsive aggression, including self-aggressive behaviour, is very common among borderline patients (Moeller et al., 2001 and Garno et al., 2005). In light of these findings, we would expect impulsivity and aggressiveness to be increased in the case of co-morbidity between bipolar and borderline personality disorder, but data supporting this assumption are limited. In fact, very few studies have been undertaken to investigate and compare impulsivity and/or aggressivity in mood disorders (including BDs) with co-morbid personality disorders, particularly borderline disorder (Henry et al., 2001, Wilson et al., 2007 and Garno et al., 2008), showing substantially that patients affected by the latter are characterised by high levels of impulsiveness and aggressiveness independent of any Axis I diagnosis. However, no studies have been devoted towards specifically evaluating the magnitude of the impact of co-morbidity of BPD on impulsivity and aggressivity in bipolar patients of both type I and II. Based on the above premises, the present study aimed to verify the hypothesis, according to which bipolar patients with co-morbid BPD (BD/BPD) are affected by a higher degree of impulsivity and aggressivity (including self-aggressiveness, as measured by attempted suicides) than patients affected by BD with other co-morbid personality disorder (BD/OPD) or bipolar disorder without Axis II co-morbidity (BD).
