Prospective: Is bipolar disorder being overdiagnosed?

OBJECTIVES

Many studies indicate that bipolar disorders are underdiagnosed. Yet from 2007 to 2008, a series of publications asserted that bipolar disorders were being overdiagnosed. This review examines the methods used in the studies that reported bipolar disorders were being overdiagnosed.

METHODS

A literature search for studies with original data related to overdiagnosis of bipolar disorders was performed.

RESULTS

Four studies were found indicating bipolar disorders were being overdiagnosed. The Structured Clinical Interview of the Diagnostic and Statistical Manual of Mental Disorders (SCID) was used in the diagnostic process. The studies compared the clinical diagnosis of bipolar disorder to a single SCID interview without interviewing family or reviewing old records. The studies assumed the SCID diagnosis was correct.

CONCLUSIONS

Numerous concerns were found. The SCID frequently missed diagnosis of bipolar, the definitions of bipolar disorder are so narrow and conservative that the outcomes of the studies may have been predetermined. Ultimately, the studies compared the strength of a diagnosis made by a treating psychiatrist to a SCID diagnosis collected with virtually no information from the clinician. The assumption that the SCID diagnosis is always correct and the clinician is always wrong is unsupportable. The premise that bipolar disorders are being overdiagnosed is unsupported by reasonable science.

Trends in diagnosis of bipolar disorder: Have the boundaries changed?

OBJECTIVE

There are concerns that the diagnostic boundaries of bipolar disorder have expanded. This study seeks evidence of change in diagnostic practice at three boundaries: the 'lower' boundary with subclinical mood conditions, the 'lateral' boundary with other mental health conditions (psychotic, anxiety, substance and personality disorders) and the 'internal' boundary within affective disorders.

METHODS

Diagnoses recorded in health system administrative data collections were used as a measure of clinician diagnostic behaviour. We examined all diagnoses made by public (state operated) inpatient and community mental health services in New South Wales, Australia, from 2003 to 2014.

RESULTS

A total of 31,746 people had at least one recorded diagnosis of bipolar disorder in the period. There was a significant upward trend in the age-standardised population rate of diagnosis of bipolar disorder. Bipolar disorders made up an increasing proportion of psychosis diagnoses. There was no increase in the rate of comorbid diagnosis of bipolar disorders with non-psychotic disorders or in the likelihood of diagnosis of bipolar disorder at first or subsequent episodes of depression. There were significant reductions in diagnoses of schizophrenia, particularly in younger people.

CONCLUSION

There may be some increase in diagnoses of bipolar disorder in New South Wales public mental health services. However, some changes in diagnosis, particularly in younger adults, may reflect movement away from diagnoses of schizophrenia towards a range of other diagnoses, rather than specific movement towards bipolar disorder. Expansion of bipolar disorder may have been more marked in private practice settings and may have involved the poorly defined bipolar II subtype.

Phenomenology of manic episodes according to the presence or absence of depressive features as defined in DSM-5: Results from the IMPACT self-reported online survey

BACKGROUND

The aim of this study was to describe the phenomenology of mania and depression in bipolar patients experiencing a manic episode with mixed features as defined in the new Diagnostic and Statistical Manual of Mental Disorders (DSM-5).

METHODS

In this multicenter, international on-line survey (the IMPACT study), 700 participants completed a 54-item questionnaire on demographics, diagnosis, symptomatology, communication of the disease, impact on life, and treatment received. Patients with a manic episode with or without DSM-5 criteria for mixed features were compared using descriptive and inferential statistics.

RESULTS

Patients with more than 3 depressive symptoms were more likely to have had a delay in diagnosis, more likely to have experienced shorter symptom-free periods, and were characterized by a marked lower prevalence of typical manic manifestations. All questionnaire items exploring depressive symptomatology, including the DSM-5 criteria defining a manic episode as "with mixed features", were significantly overrepresented in the group of patients with depressive symptoms. Anxiety associated with irritability/agitation was also more frequent among patients with mixed features.

LIMITATIONS

Retrospective cross-sectional design, sensitive to recall bias. Two of the 6 DSM-5 required criteria for the specifier "with mixed features" were not explored: suicidality and psychomotor retardation.

CONCLUSIONS

Bipolar disorder patients with at least 3 depressive symptoms during a manic episode self-reported typical symptomatology. Anxiety with irritability/agitation differentiated patients with depressive symptoms during mania from those with "pure" manic episodes. The results support the use of DSM-5 mixed features specifier and its value in research and clinical practice.

Utilization of never-medicated bipolar disorder patients towards development and validation of a peripheral biomarker profile

There are currently no biological tests that differentiate patients with bipolar disorder (BPD) from healthy controls. While there is evidence that peripheral gene expression differences between patients and controls can be utilized as biomarkers for psychiatric illness, it is unclear whether current use or residual effects of antipsychotic and mood stabilizer medication drives much of the differential transcription. We therefore tested whether expression changes in first-episode, never-medicated BPD patients, can contribute to a biological classifier that is less influenced by medication and could potentially form a practicable biomarker assay for BPD. We employed microarray technology to measure global leukocyte gene expression in first-episode (n=3) and currently medicated BPD patients (n=26), and matched healthy controls (n=25). Following an initial feature selection of the microarray data, we developed a cross-validated 10-gene model that was able to correctly predict the diagnostic group of the training sample (26 medicated patients and 12 controls), with 89% sensitivity and 75% specificity (p<0.001). The 10-gene predictor was further explored via testing on an independent cohort consisting of three pairs of monozygotic twins discordant for BPD, plus the original enrichment sample cohort (the three never-medicated BPD patients and 13 matched control subjects), and a sample of experimental replicates (n=34). 83% of the independent test sample was correctly predicted, with a sensitivity of 67% and specificity of 100% (although this result did not reach statistical significance). Additionally, 88% of sample diagnostic classes were classified correctly for both the enrichment (p=0.015) and the replicate samples (p<0.001). We have developed a peripheral gene expression biomarker profile, that can classify healthy controls from patients with BPD receiving antipsychotic or mood stabilizing medication, which has both high sensitivity and specificity. Moreover, assay of three first-episode patients who had never received such medications, to first enrich the expression dataset for disease-related genes independent of medication effects, and then to test the 10-gene predictor, validates the peripheral biomarker approach for BPD.

Mixed states in DSM-5: implications for clinical care, education, and research

The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) nomenclature for the co-occurrence of manic and depressive symptoms (mixed states) has been revised in the new DSM-5 version to accommodate a mixed categorical-dimensional concept. The new classification will capture subthreshold non-overlapping symptoms of the opposite pole using a "with mixed features" specifier to be applied to manic episodes in bipolar disorder I (BD I), hypomanic, and major depressive episodes experienced in BD I, BD II, bipolar disorder not otherwise specified, and major depressive disorder. The revision will have a substantial impact in several fields: epidemiology, diagnosis, treatment, research, education, and regulations. The new concept is data-driven and overcomes the problems derived from the extremely narrow definition in the DSM-IV-TR. However, it is unclear how clinicians will deal with the possibility of diagnosing major depression with mixed features and how this may impact the bipolar-unipolar dichotomy and diagnostic reliability. Clinical trials may also need to address treatment effects according to the presence or absence of mixed features. The medications that are effective in treating mixed episodes per the DSM-IV-TR definition may also be effective in treating mixed features per the DSM-5, but new studies are needed to demonstrate it.

To be or not to be a bipolar disorder patient: problems with diagnosis

The diagnosis of bipolar disorder (BD) is predominantly clinical. Some authors have suggested that BD is underdiagnosed and that many patients, particularly those with major depressive disorder, actually have BD. Some studies have suggested that BD is wrongly diagnosed, probably because of the idea of a "bipolar spectrum." To address this potential overdiagnosis, clinicians should carefully and systematically assess whether symptoms are included in diagnostic criteria and include the individual context of the patient.

Diagnosing bipolar disorder in the community setting

BACKGROUND

Bipolar disorder (BD) is a common psychiatric illness. Diagnosing this condition is challenging, due to the frequent need to make the diagnosis based on historical symptoms, the lack of specificity of many of the symptoms, and the absence of accurate objective measures to confirm the diagnosis. A lack of consensus among psychiatrists as to the breadth of the diagnosis, increasing pressures to make a diagnosis quickly in clinical settings, and the availability of broader spectrum treatments have also served to foster uncertainty in diagnosis. This article examines the process of diagnosing BD, reviews factors that can confound the diagnostic process, and discusses how the sensitivity and specificity of the diagnosis can be improved.

METHODS

A MEDLINE search and a manual search of textbooks and abstracts from scientific meetings were conducted. Results were limited to publications in English, but no timeframe limitations were used.

RESULTS

The standard for diagnosing BD remains the psychiatric interview, with laboratory, genetic, radiographic, and neuroimaging tests still investigational, and psychological tests and questionnaires serving an ancillary role. The sensitivity and specificity of the BD diagnosis is less than optimal, with the condition being both overlooked and diagnosed when it is not present.

CONCLUSIONS

Factors leading to diagnostic uncertainty and approaches to improve the sensitivity and specificity of the BD diagnosis are discussed. A paradigm for differentiating between BD and borderline personality disorder is offered.

Bipolar II disorder in rural New South Wales

OBJECTIVE

To determine the frequency with which bipolar II disorder (BD II) was diagnosed in clinics held in four rural towns in New South Wales (NSW).

METHOD

A retrospective case file audit was conducted for patients referred for psychiatric assessment and treatment in four towns in rural NSW over a period of two years and nine months.

RESULTS

Of 559 patients seen for the first time during the study period, 113 (20.2%) were diagnosed with BD II, and of these this diagnosis was made for the first time in 69 patients (61%). Associated clinical findings in BD II patients are presented and a comparison is made with patients with non-bipolar depression seen during the same period.

CONCLUSION

BD II was commonly seen in these rural clinics, and appears to be often under-diagnosed in general practice, as has been found to be the case in urban centres. This is seen as a serious public health problem, which needs to be addressed by educational steps directed at general practitioners (GPs), mental health clinicians, and perhaps also the general public.