Depolarising bipolarity: Clinical considerations

Some years ago, in an Editorial in the Australian & New Zealand Journal of Psychiatry (ANZJP), we described the process of removing an incorrect diagnosis of bipolar disorder and termed it ‘depolarisation’. In this Editorial, we return to discuss how the recognition of misdiagnosis is driving the need for depolarisation and to outline some important considerations for clinicians to bear in mind when instituting this process.

Misdiagnosis is at the heart of the increasing need to depolarise patients, and broadly speaking, the reasons for patients being mislabelled as ‘bipolar’ are threefold. First, it is important to acknowledge that some problems in diagnosing bipolar disorder are essentially unavoidable because they stem from the very nature of the illness and, as such, are difficult to tackle – especially within the constraints of anamnesis. Second, symptoms typically evolve over time, and many people can display various phenotypes cross-sectionally. Finally, it is necessary to realise that there are many clinical factors that can in fact be addressed to significantly improve the diagnosis of bipolar disorder and thus reduce the need for depolarisation.

Diagnosis

Misdiagnosis

The intrinsic nature of bipolar disorder is that depression usually precedes the onset of manic symptoms: hence early in the course of the illness, the initial diagnosis is usually that of major depression and only once manic symptoms emerge can bipolar disorder be identified. This inevitable delay in diagnosis, coupled with heightened awareness of bipolar disorder and the need for early detection, has meant that both patients and clinicians may anticipate the illness and be overly sensitive to symptoms indicative of bipolarity. Ordinarily, this is good practice – and being aware of the diagnosis and suitably attuned to its symptoms is to be encouraged. But if this is coupled with a low threshold for diagnosis, or aversion for an alternative diagnosis such as borderline personality, it can lead to premature closure on formulation and incorrect diagnosis. In practice, bipolar disorder is increasingly overused as an explanation for modest disturbances of mood (Malhi and Porter, 2014).

Arguably, the bipolar subtype most prone to misdiagnosis is Bipolar II Disorder, which is fundamentally no different to Bipolar I Disorder, with the exception of potentially featuring psychosis, but its arbitrary diagnostic cut-offs based on the duration of symptoms make diagnosis imprecise (Malhi and Berk, 2014). Consequently, there has been copious conjecture regarding the putative over-diagnosis of bipolar disorder, and some have suggested that the contrary is equally true.

A key contributor to this confusion is the description of mood disorders and its ‘subtypes’ in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Published in 2013, DSM-5 has sparked vigorous debate concerning psychiatric taxonomy, for example, the strengths and weaknesses of ‘top-down’ versus ‘bottom-up’ frameworks for classification, in other words phenomenology versus neurobiology, and the clinical validity of diagnostic ‘categories’ created by splicing symptoms that invariably exist along continuums (Malhi, 2013; Sachdev, 2013). Other changes risk blurring the margins of bipolar disorder further, particularly the DSM-5’s introduction of a mixed features specifier in non-bipolar depression. It is important to note that this is not just a theoretical debate, but one with many important clinical ramifications. For example, symptoms of hypomania in bipolar II disorder are often difficult to distinguish from normalcy, and yet, when they are extreme, they can prove difficult to separate from bipolar I disorder mania or mood symptoms that occur within co-morbid syndromes.

Assigning a diagnosis of bipolar disorder usually results in the prescription of concordant medications. The diagnosis also connotes that the clinical presentation is driven by mood instability that can be exacerbated with treatment, for example, antidepressants precipitating manic symptoms and antipsychotics producing depressive symptoms. If the diagnosis is incorrect, the risk of ‘non-response’ and hence greater than normative doses and polypharmacy increases. This risk carries greater weight given that the benefits are limited. Equally, there is an opportunity cost in following a diagnostic algorithm path that means that potentially more appropriate therapies, such as dialectical behaviour therapy (DBT), are less likely to be adopted. Thus, an incorrect bipolar diagnosis has many potentially serious consequences.

With increasing bipolar disorder awareness, ‘Dr Google’, and widespread availability of self-rating instruments – many of which have poor sensitivity or specificity, especially in community cohorts – patients often present with a presumptive diagnosis. Rather than asking, ‘Do you think I am depressed?’ they are increasingly likely to state, ‘I think I have bipolar disorder’. A key problem then emerges, as challenging earlier assumptions becomes increasingly difficult, and the revision of an incorrect diagnosis becomes less and less likely. Hence, patients presenting with unstable mood symptoms, often identified and rated using self-report measures, risk being diagnosed as having bipolar disorder. At each successive consultation, because existing diagnoses are assumed to be correct, the diagnosis risks being strengthened rather than questioned. Ultimately, consolidation of the diagnosis takes place as ‘antibipolar’ medications are commenced – substantiating through therapy that the individual does indeed have bipolar disorder.

The dissection and partitioning of these syndromes using our rather blunt instruments are made all the more difficult in youth, when clinical symptoms are set against the backdrop of rapid adolescent emotional and cognitive development. Adolescence makes the task of diagnosis profoundly challenging, and it is arguable whether an incorrect diagnosis is worse than a delay in diagnosis or a failure to detect the illness altogether.

Diagnosing bipolar disorder

Clearly, the best scenario is to avoid the misdiagnosis of bipolar disorder in the first place and to institute optimal treatment from the outset. But, as discussed above, there are some inherent limitations to accurately diagnosing bipolar disorder, especially early in its course. However, some steps can and should be taken to improve its diagnosis, in particular that of bipolar II disorder.

First, a thorough history of manic symptoms is important, noting the extent and pattern of any elevation in mood, heightened irritability and any increase in psychomotor activity. This should be gauged against what is normal/usual for the individual. As a general rule, the threshold for suspicion should be low, necessitating detailed inquiry of manic symptoms, but the threshold for diagnosis should be high – all the while seeking alternative explanations for symptoms prior to concluding that they are indicative of mania. Presentations that fall in between these thresholds need to be monitored closely and a diagnosis should be deferred until more information is available, or the clinical picture becomes clearer. To assist in this, patients should be advised to keep a detailed mood diary, corroborative information should be sought from separate sources, and a careful and equally weighted assessment of personality, anxiety and substance misuse should also be undertaken.

While there is still doubt about the diagnosis, it is important to resist commencing any treatment. If this becomes necessary, then medication should be prescribed for the shortest time possible and its necessity reviewed regularly. Given the overlap among patterns of treatment utility between diagnostic categories, it is sometimes possible to choose therapies that span multiple categories or to avoid those that pose particular risks to one differential diagnostic category. Note that this is the time to seek a second opinion – not after making the diagnosis and instituting treatment! At this time, in conversations with the patient, it is important to emphasise that the diagnosis of bipolar disorder is only being considered and is by no means decided – even if the patient is convinced that they are bipolar.

To assign a diagnosis of bipolar II disorder, the duration of hypomanic symptoms must be 4 days or more, and no less, and each of the key symptoms should be unequivocally present and clearly documented, both in terms of severity and duration. Even then, a diagnosis of bipolar II disorder should be considered carefully, noting its high comorbidity and that many other syndromes can masquerade as bipolar disorder.

Depolarising bipolarity

Depolarisation

Depolarising bipolar disorder is not a simple and straightforward matter. It too has potentially serious consequences. Usually by the time depolarisation is considered, patients have already undergone assessment by several clinicians. They have often received in-depth psychoeducation regarding bipolar disorder, and many medications are likely to have been prescribed and trialled. Together, courses of psychological therapy, combinations of medications and the effects of the illness itself are all likely to have had a significant impact on the individual’s quality of life. Complicating this, a degree of illness investment can set in, with an acceptable diagnosis providing a foil for life’s vicissitudes (Berk et al., 2013). Therefore, in addition to altering management, revision of the diagnosis at this juncture has many potentially significant psychological implications. For example, removing the diagnosis of bipolar disorder can be construed as a ‘downgrading’ of their illness by some patients. And, strangely, bipolar disorder for some can be more ‘appealing’ than either major depression or, particularly, borderline personality disorder.

Depolarisation also runs the risk of disrupting otherwise functional and necessary therapeutic relationships (e.g. with a treating general practitioner, psychiatrist or psychologist). Patients may react with anger and resentment because of lost time through misdiagnosis and its consequences, including incorrectly targeted management and unnecessary prolongation of their suffering. Ironically, depolarising an individual with an incorrect diagnosis of bipolar disorder may not neutralise matters but instead further ‘charge’ the situation – a considerable challenge if the primary diagnosis is a personality disorder with all the attendant attachment dynamics.

When depolarising, it is important to emphasise to all concerned that diagnosing bipolar disorder is a complex process, which is especially difficult early in its course. And there is no objective diagnostic marker – long the holy grail of biological psychiatry. Once the diagnosis is revised, it is necessary to review the medication regimen. In most instances, long-term mood stabilising medications such as lithium, antipsychotic medication and anticonvulsants may no longer be needed, unless they have demonstrably benefitted symptomatology. Depolarisation is further complicated by the not insubstantial overlap between the evidence of utility of, for example, antipsychotics and anticonvulsants across bipolar, unipolar and borderline categories, and this can be especially problematic if it involves the prescription of medications that require a particular diagnostic indication. In these instances, off-label prescribing is an option, but is usually much more expensive. Psychodynamically, especially if the revised diagnosis is a personality disorder, medication withdrawal needs to be achieved cautiously, as it can lead to an abandonment dynamic, and there may equally be pharmacokinetic risks of withdrawal and relapse.

However, if the diagnosis of bipolar disorder is deemed to be incorrect and the individual has to be depolarised, then medication changes will also need to follow suit. An important caveat reflecting the phenotypic instability and diagnostic imprecision inherent in the field is that occasionally the diagnosis, although presently incorrect, may indeed become the correct diagnosis if the individual develops bipolar disorder in the future. Therefore, this possibility also needs to be considered with humility and raised with the depolarised individual.

Clinical considerations

Just as the diagnosis of bipolar disorder requires a high threshold, so too should its depolarisation. If a diagnosis of bipolar disorder is suspected to be incorrect, then a detailed evaluation is necessary and a second opinion, ideally from an expert, should be sought. A diagnostic review at this stage will require reviewing periods of illness, unadulterated by treatment and the collation and review of facts from earlier episodes in the course of the illness.

Diagnostic review of bipolar disorder may also have been prompted by new information coming to light, such as the concomitant misuse of substances and underlying anxiety and personality traits. In such instances, a careful assessment is warranted with a view to reformulating the diagnosis. With this new information in mind, if the diagnosis has to be revised, then all concerned should be made aware of this decision and a clear explanation and management plan should be communicated. An appropriate explanation is also needed for the patient undergoing depolarisation. Having taken away the diagnosis of bipolar disorder, a palatable substitute might be, ‘Perhaps it’s just your nature that your mood wobbles a bit …’.

It is important to note that depolarisation is not a re-setting or re-booting of the diagnostic process, and the patient will certainly not view it as such. Instead, it is part of an evolving process in which, as a clearer picture emerges and new information is acquired, a more accurate diagnosis becomes possible. It also needs to be communicated with humility that diagnosis is an imprecise art, that the field lacks definitive tests and that diagnoses can change and are in reality no more than adjectives or metaphors. This provides a constructive framework for all concerned, including the patient, and allows existing therapeutic relationships to be maintained.

Conclusion

The absence of a cogent measureable neurobiology and the consequent and inevitable failures of all diagnostic systems, including DSM-5, International Classification of Diseases, 10th Revision (ICD-10) and Research Domain Criteria (RDoC), further highlight the risk of incorrect diagnosis. Hence, the need for depolarisation is likely to remain – and therefore even with the greatest of caution, some incorrect diagnoses will be made. It is thus imperative that we better understand this difficult process and afford it greater consideration when managing patients with putative bipolarity.