Both borderline personality disorder and broadly defined bipolar disorder are common (prevalence: 1-6%). Comorbidity occurs in approximately 1 in 5 (Fornaro et al, 2016) with a high symptom overlap; impulsivity, suicidal behaviour and affective instability.

This commonly leads to misdiagnosis in outpatient settings:

• 25% of patients diagnosed with bipolar disorder were, in fact, borderline personality disorder patients
• 44% of borderline personality disorder patients had their diagnosis corrected to bipolar disorder.

The problem of misdiagnosis spans psychiatry as this occurs in other conditions (Vöhringer, et al 2016; OConghaile et al, 2015; Zbozinek et al, 2012).

Bipolar disorder and borderline personality disorder differ in treatment and prognosis:

• Borderline personality disorder is usually treated with psychological therapy and may be in remission after 6 years
• Bipolar disorder is usually treated with medication and is a lifelong relapsing condition.

A qualitative study of how psychiatrists and nurses distinguish bipolar disorder from borderline personality disorder

32 secondary care psychiatrists and nurses used semi-structured interviews mostly in a community-mental-teams setting. Clinicians found differential diagnosis difficult because of the symptom overlap in relation to the following:

• Mood instability
• The need to rely on self-reported mood symptoms
• Inaccurate retrospective recall
• Chaotic lifestyles
• Illicit drug use
• Conducting diagnostic assessments in crisis situations

Many clinicians felt that diagnosing bipolar disorder was more important. However, as one psychiatrist rightly pointed out:

If you go to someone who’s got borderline-type problems, and you just try to find out if they’ve got bipolar – have had a hypomanic episode, and you just ask your questions in that way, you’d be very likely to erroneously conclude that they have had a hypomanic episode.

Clinician survey of diagnostic knowledge and experience

A survey of 648 psychiatrists’ (70% consultants) knowledge and use of diagnostic criteria when distinguishing bipolar disorder and borderline personality disorder, found 76% of respondents felt confident in their ability to discriminate between the 2 conditions. However, 52% of respondents indicated this was a source of disagreement.

Even though respondents’ knowledge matched DSM-IV-TR, only half of respondents preferred using diagnostic criteria; but 84% and 75% of respondents thought diagnostic criteria matched the clinical presentation of bipolar disorder and borderline personality disorder, respectively. Only 6% endorsed borderline personality disorder occurring comorbidly with bipolar disorder as a fairly frequent occurrence in their practice, which is substantially different to published accounts, as mentioned above.

An observational study of the diagnostic assessment process in ordinary practice

When analysing audio recordings of 18 patient interviews in secondary care, depressive symptoms were adequately assessed in 61% of cases but in 20% of cases elevated mood was not addressed at all. Enough symptoms were explored to affirm borderline personality disorder in 22% of cases.

Experienced psychiatrists’ diagnoses were compared to OPCRIT (Operational CRITeria), a diagnostic system that automates the generation of diagnoses using a checklist constructed from the major psychiatric diagnostic classifications. The agreement between diagnoses and OPCRIT was 5 out of 18. Of the 7 patients given a diagnosis of bipolar disorder 3 had bipolar disorder according to OPCRIT. Of the 5 patients given a diagnosis of borderline personality disorder, OPCRIT suggested 1 had bipolar disorder and 4 had other conditions.

Summary

There may be previous studies that examine new diagnostic methods, but I am not aware of other research that examines common practice in this level of detail. 

What is troubling is that not enough information was available to clinicians to establish anything other than depression. Even more so, they proceeded to diagnose without enough information.

When considering the survey and clinical practice data in tandem, clinicians’ views about how diagnostic criteria represent clinical practice manifest as a minority of assessments being sufficiently assessed for symptoms of mania or borderline personality disorder and largely conflict with OPCRIT diagnoses. Instead we see some factors as heavily influencing the differential diagnosis such as an abusive past or a family history of psychiatric disorders. Whilst these associations are supported by research (Distel et al, 2008; Kendler et al, 2008; Zanarini et al, 1989), they are not exclusive to either condition. This is in agreement with previous reports on clinical practice (Aboraya, 2009). If all psychiatrists use impressionistic approaches the utility of diagnostic labels to inform treatment and communication become fundamentally flawed, as do their medico legal defensibility.

The paper quotes one psychiatrist:

So I think if you’re someone who goes, what do I feel this patient is presenting to me with? Or you’re someone who goes well, what boxes am I ticking, I think that that then leads you down two different routes in terms of thinking about diagnosis.

Of course, he is absolutely correct, however, another psychiatrist is quoted:

I challenge anyone to be able to say what their mood’s like reliably over that period of time.

If you apply this to psychiatrists instead of patients you find that this eloquently describes the problem with impressionistic approaches; their inherent vulnerability to variation and inaccuracies. All medical and medical-affiliated professions are pushed towards evidence-based-practice for good reason, but this paper shows practice in direct opposition to this principal.

One problem may be that clinicians are aiming to manage the condition as a whole, hence, an overarching label is useful. However, both these conditions exist on a spectrum. It may aid standardisation or evidence based practice if the aim was to manage symptom clusters. At the very least, it may incentivise clinicians to elicit more information from their patients.

Where appropriate, this article largely satisfied the CASP checklist for qualitative studies (PDF). Of particular note was the 8.1% response rate for the survey, but it did cover a considerable portion of the UK, many different contexts and reached data saturation, but it may have suffered from self-selection bias and the number of clinicians included in the qualitative study was small.

Links

Primary paper

Saunders KEA, et al. Distinguishing bipolar disorder from borderline personality disorder: A study of current clinical practice. European Psychiatry 2015:30(8):965-974. [Abstract]

Other references

Fornaro M, et al. (2016) The prevalence and predictors of bipolar and borderline personality disorders comorbidity: Systematic review and meta-analysis. J Affect Disord. 2016;195:105-18. [PubMed abstract]

Vöhringer PA, et al. (2016) Discriminating Between Bipolar Disorder and Major Depressive Disorder. Psychiatr Clin North Am. 2016;39(1):1-10. doi: 10.1016/j.psc.2015.10.001. [PubMed abstract]

OConghaile A, et al. (2015) Distinguishing schizophrenia from posttraumatic stress disorder with psychosis. Curr Opin Psychiatry. 2015;28(3):249-55. [PubMed abstract]

Zbozinek TD, et al. (2012) Diagnostic overlap of generalized anxiety disorder and major depressive disorder in a primary care sample. Depress Anxiety. 2012;29(12):1065-71.

Distel MA, et al. (2008) Heritability of borderline personality disorder features is similar across three countries. Psychol Med 2008;38(9):1219–29. [PubMed abstract]

Kendler KS, et al. (2008) The structure of genetic and environmental risk factors for DSM-IV personality disorders: a multivariate twin study. Arch Gen Psychiatry 2008;65(12):1438–46.

Zanarini MC, et al. (1989) Childhood experiences of borderline patients. Compr Psychiatry 1989;30(1):18–25. [PubMed abstract]

Aboraya A. (2009) Use of structured interviews by psychiatrists in real clinical settings: results of an open-question survey. Psychiatry 2009;6(6):24–8.

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