The term “borderline” is a misnomer, based on an old theory that this form of pathology lies on a border between psychosis and neurosis. Actually, BPD is a complex syndrome whose central features are instability of mood, impulse control and interpersonal relationships.2
presents the DSM-IV-TR1
criteria, reorganized in relation to these basic dimensions, as well as cognitive symptoms. Since the DSM-IV-TR requires only 5 of 9 criteria to be present, making a diagnosis on this basis leads to heterogeneity; more precise research definitions have been developed that require high scores for all 3 dimensions.18
The affective symptoms in BPD involve rapid mood shifts, in which emotional states tend to last only a few hours.19
When affective instability is monitored with standardized instruments,20
emotions are found to be intense but reactive to external circumstances, with a strong tendency toward angry outbursts. Levels of affective instability are most predictive of suicide attempts.21
Impulsive symptoms include a wide range of behaviours and are central to diagnosis.22
The combination of affective instability with impulsivity in BPD23
helps account for a clinical presentation marked by chronic suicidality and by instability of interpersonal relationships.23
Finally, cognitive symptoms are also frequent. In one case series,24
about 40% of 50 patients with BPD had quasi-psychotic thoughts. In another series,25
27% of 92 patients experienced psychotic episodes. In a third series,26
psychotic symptoms were found to predict self-harm in patients with personality disorders.
BPD is common in practice. A recent study involving patients in an emergency department who had attempted suicide showed that 41% of those with a history of multiple suicide attempts met the criteria for BPD this disorder.27
However, many cases are also seen in primary care settings. Data from a survey conducted in a US urban primary care practice indicated that BPD was present in 6.4% of a sample of 218 patients.28
Because of the wide range of symptoms seen in BPD that are also typical of other disorders (), such as mood and anxiety disorders, substance abuse and eating disorders,29
patients may be felt to have one of these conditions while their BPD goes undetected. The most common disorder associated with BPD is depression, but in BPD, symptoms are usually associated with mood instability rather than with the extended and continuous periods of lower mood seen in classic mood disorders.19
Also, because of characteristic mood swings, BPD is often mistaken for bipolar disorder.30
However, patients with BPD do not show continuously elevated mood but instead exhibit a pattern of rapid shifts in affect related to environmental events, with “high” periods that last for hours rather than for days or weeks.30
BPD may be mistaken for schizophrenia; however, instead of long-term psychotic symptoms, patients with BPD experience “micropsychotic” phenomena of short duration (lasting hours or at most a few days), auditory hallucinations without loss of insight (patients with schizophrenia do not recognize that a hallucination is imaginary, whereas patients with BPD do), paranoid trends and depersonalization states in which patients experience themselves or their environment as unreal.24
Finally, patients with BPD are at increased risk of substance abuse, which forms part of the clinical picture of widespread impulsivity.2
To diagnose BPD in practice, clinicians must first establish whether a patient has the overall characteristics of a personality disorder described in the DSM-IV-TR;1
that is, long-term problems affecting cognition, mood, interpersonal functioning and impulse control that begin early in life and are associated with maladaptive personality traits, such as neuroticism (being easily prone to anxiety or depression, or both) or impulsivity. Personality disorders can often account better for the multiplicity and chronicity of symptoms than can alternative diagnoses such as mood or anxiety disorders.
The next step is a personality assessment, which requires a good history. Although practitioners will be able to obtain needed information from most patients during a routine visit, they may also, with the patient's consent, wish to speak to family members or friends.
The final step is to determine the category that best fits the clinical picture. To diagnose BPD, clinicians need to establish that patterns of affective instability, impulsivity and unstable relationships have been consistent over time.