Crawford et al (1) discuss very appropriately the difficulty in deciding whether patients with borderline personality disorder should be treated with mood stabilisers.
This raises the important issue that it is possible for patients to suffer from two comorbid but distinct conditions; Bipolar II Affective Disorder, and Borderline Personality Disorder. Bipolar Disorder is basically an illness with an important genetic component, often related to a family history of the illness, while Borderline Personality Disorder has mostly an environmental component, including often the fact that the sufferer has been exposed to abuse. However it is indeed possible that both conditions may exist in the same patient (2).
Mood stabilisers are essential treatment for patients who suffer from bipolar disorder, since they are essential in stabilising mood and reducing suicidality (3).
Patients with borderline personality disorder, who do not have comorbid bipolar disorder, do demonstrate mood lability, but do not demonstrate hypomanic or manic episodes, as defined by DSM V, in other words they do not demonstrate a history of at least 4 days of clearly euphoric [high]mood(2).
Borderline patients may instead demonstrate mood lability, as in changes from euthymicity to depressed mood and back again, and also impulsivity, but this does not indicate hypomanic episodes required to diagnose bipolar illness (2).
However, there do occur cases when borderline traits can be co-morbid with bipolar disorder(4). If the bipolar illness is ignored in these cases, so that the patients are only diagnosed as having borderline personality disorder, then these bipolar patients will not be diagnosed , and hence they will not receive the mood stabilising treatment they need. This will have an impact on their prognosis, since patients with Bipolar II are known to have a relatively high risk of suicidality (5), and this can be expected to be exacerbated by the impulsivity and self harming behaviour caused by the comorbid borderline traits.
We therefore propose that patients with possible borderline personality disorder be carefully assessed for hypomanic episodes as described in DSM(6). If they can be shown to have such episodes, then a diagnosis of Bipolar Disorder with comorbid borderline features can be considered , while if not then the patients may well have borderline personality disorder alone. Only if the patients are shown to have bipolar disorder should mood stabilisation be prescribed.
We have recently been able to demonstrate that bipolar disorder is still often underdiagnosed in community mental health teams(7), and this implies risk to the patients not diagnosed. We feel that misdiagnosis of bipolar disorder comorbid with borderline traits does contribute to this misdiagnosis. We have also been able to publish an audit which shows that by adopting the policy of identifying hypomanic episodes, we found that in our sample, 14.66% of patients were found to have bipolar disorder co-morbid with borderline personality disorder , and therefore we did not exceed the number of patients [12-23%] which are predicted in the international literature as having both borderline and bipolar conditions(6).
1.Crawford M, MacLaren T, Reilly JG Are mood stabilisers helpful in treatment of borderline Personality Disorder? BMJ 2014:349:g5378.
2. Ghaemi SN, Dalley S, Catania C, Barroilhet S. Bipolar or borderline: a clinical overview. ActaPsychiatrScand 2014: 130: 99–108
3.Bipolar disorder: the assessment and management of bipolar disorder in adults, children and young people in primary and secondary care NICE 2014
4..Elisei S, Anastasi S, VerdoliniN.The continuum between Bipolar Disorder and Borderline Personality Disorder.PsychiatrDanub. 2012 Sep;24Suppl 1:S143-6
5.Costa LD, Alencar AP, Neto PJ, Santos MD, da Silva CG, Pinheiro SD, TeixeiraSilveira R, Bianco BA, PinheiroJúnior RF, de Lima MA, Reis AO, Neto MLRisk factors for suicide in bipolar disorder: A systematic review.J Affect Disord. 2014 Sep 16;170C:237-254.
6.Agius M, Lee J, Gardner J, Wotherspoon D. Bipolar II Disorder and Borderline Personality Disorder - co-morbidity or spectrum?PsychiatrDanub. 2012 Sep;24Suppl 1:S197-201
7. Bongards EN, Zaman R, Agius M. Can we prevent under-diagnosis and misdiagnosis of bipolar affective disorder? Repeat audits to assess the epidemiological change in the caseload of a community mental health team when bipolar disorder is accurately assessed and diagnosed.PsychiatrDanub. 2013 Sep;25Suppl 2:S129-34
Competing interests: No competing interests