Mood disorders
Many people with borderline personality disorder also have mood disorders, such as major depressive disorder or a bipolar disorder. Some characteristics of BPD are similar to those of mood disorders, which can complicate the diagnosis. It is especially common for people to be misdiagnosed with bipolar disorder when they have borderline personality disorder or vice versa. For someone with bipolar disorder, behavior suggestive of BPD might appear while experiencing an episode of major depression or mania, only to disappear once mood has stabilized. For this reason, it is ideal to wait until mood has stabilized before attempting to make a diagnosis.At face value, the affective lability of BPD and the rapid mood cycling of bipolar disorders can seem very similar. It can be difficult even for experienced clinicians, if they are unfamiliar with BPD, to differentiate between the mood swings of these two conditions. However, there are some clear differences.First, the mood swings of BPD and bipolar disorder tend to have different durations. In some people with bipolar disorder, episodes of depression or mania last for at least two weeks at a time, which is much longer than moods last in people with BPD. Even among those who experience bipolar disorder with more rapid mood shifts, their moods usually last for days, while the moods of people with BPD can change in minutes or hours.
Women tend to turn their anger on themselves, leading to depression as well as the cutting and overdosing that characterize BPD. Thus, anti-social personality disorder (ASPD) and borderline personality disorders might derive from similar underlying pathology but present with symptoms strongly influenced by gender (Paris, 1997a; Looper & Paris, 2000). We have even more specific evidence that men with BPD may not seek help. In a study of completed suicides among people aged 18 to 35 years (Lesage et al., 1994), 30% of the suicides involved individuals with BPD (as confirmed by psychological autopsy, in which symptoms were assessed by interviews with family members). Most of the suicide completers were men, and very few were in treatment. Similar findings emerged from a later study conducted by our own research group (McGirr, Paris, Lesage, Renaud, & Turecki, 2007). In short, men are less likely to seek or accept appropriate treatment, more likely to be treated for symptoms of BPD such as substance use rather than BPD itself (the symptoms of BPD and ASPD possibly deriving from a similar underlying etiology); more likely to wind up in the correctional system due to criminal behavior; and, more likely to commit suicide prior to diagnosis. Among men diagnosed with BPD there is also evidence of a higher suicide rate: "men are more than twice as likely as women—18 percent versus 8 percent"—to die by suicide.There are also sex differences in borderline personality disorders.