Bipolar II disorder: an overview of recent developments

Bipolar disorder in the International Classification of Diseases-Eleventh version: A review of the changes, their basis, and usefulness

The World Health Organization’s 11^th revision of the International Classification of Diseases (ICD-11) including the chapter on mental disorders has come into effect this year. This review focuses on the “Bipolar or Related Disorders” section of the ICD-11 draft. It describes the benchmarks for the new version, particularly the foremost principle of clinical utility. The alterations made to the diagnosis of bipolar disorder (BD) are evaluated on their scientific basis and clinical utility. The change in the diagnostic requirements for manic and hypomanic episodes has been much debated. Whether the current criteria have achieved an optimum balance between sensitivity and specificity is still not clear. The ICD-11 definition of depressive episodes is substantially different, but the lack of empirical support for the changes has meant that the reliability and utility of bipolar depression are relatively low. Unlike the Diagnostic and Statistical Manual of Mental Disorders, 5^th edition (DSM-5), the ICD-11 has retained the category of mixed episodes. Although the concept of mixed episodes in the ICD-11 is not perfect, it appears to be more inclusive than the DSM-5 approach. Additionally, there are some uncertainties about the guidelines for the subtypes of BD and cyclothymic disorder. The initial results on the reliability and clinical utility of BD are promising, but the newly created diagnostic categories also appear to have some limitations. Although further improvement and research are needed, the focus should now be on facing the challenges of implementation, dissemination, and education and training in the use of these guidelines.

Clinical and psychopathological features associated with treatment-emergent mania in bipolar-II depressed outpatients exposed to antidepressants

BACKGROUND

Treatment-emergent affective switch (TEAS), including treatment-emergent mania (TEM), carry significant burden in the clinical management of bipolar depression, whereas the use of antidepressants raises both efficacy, safety and tolerability concerns. The present study assesses the prevalence and clinical correlates of TEM in selected sample of Bipolar Disorder (BD) Type-II (BD-II) acute depression outpatients.

METHODS

Post-hoc analysis of the clinical and psychopathological features associated with TEM among 91 BD-II depressed outpatients exposed to antidepressants.

RESULTS

Second-generation antipsychotics (SGA) (p = .005), lithium (≤ .001), cyclothymic/irritable/hyperthymic temperaments (p = ≤ .001; p = .001; p = .003, respectively), rapid-cycling (p = .005) and depressive mixed features (p = .003) differed between TEM⁺ cases vs. TEM^- controls. Upon multinomial logistic regression, the accounted psychopathological features correctly classified as much as 88.6% of TEM⁺ cases (35/91 overall sample, or 38.46% of the sample), yet not statistically significantly [Exp(B) = .032; p = ns]. Specifically, lithium [B = - 2.385; p = .001], SGAs [B = - 2.354; p = .002] predicted lower rates of TEM⁺ in contrast to the number of lifetime previous psychiatric hospitalizations [B = 2.380; p = .002], whereas mixed features did not [B = 1.267; p = ns].

LIMITATIONS

Post-hoc analysis. Lack of systematic pharmacological history record; chance of recall bias and Berkson's biases. Permissive operational criterion for TEM. Relatively small sample size.

CONCLUSIONS

Cyclothymic temperament and mixed depression discriminated TEM⁺ between TEM^- cases, although only lithium and the SGAs reliably predicted TEM^+/- grouping. Larger-sampled/powered longitudinal replication studies are warranted to allow firm conclusions on the matter, ideally contributing to the identification of clear-cut sub-phenotypes of BD towards patient-tailored-pharmacotherapy.

Incidence, prevalence and clinical correlates of antidepressant-emergent mania in bipolar depression: a systematic review and meta-analysis

BACKGROUND

Treatment-emergent mania (TEM) represents a common phenomenon inconsistently reported across primary studies, warranting further assessment.

METHODS

A systematic review and meta-analysis following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) and Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines were conducted. Major electronic databases were searched from inception to May 2017 to assess the incidence and prevalence rates and clinical features associated with manic switch among bipolar depressed patients receiving antidepressants, using meta-regression and subgroup analysis.

RESULTS

Overall, 10 098 depressed patients with bipolar disorder (BD) across 51 studies/arms were included in the quantitative analysis. The cumulative incidence of cases (TEM⁺ ) among 4767 patients with BD over 15 retrospective studies was 30.9% (95% confidence interval [CI] 19.6-45.0%, I²  = 97.9%). The cumulative incidence of TEM⁺ among 1929 patients with BD over 12 prospective open studies was 14.4% (95% CI 7.4-26.1%, I²  = 93.7%). The cumulative incidence of TEM⁺ among 1316 patients with BD over 20 randomized controlled trials (RCTs) was 11.8% (95% CI 8.4-16.34%, I²  = 73.46%). The pooled prevalence of TEM⁺ among 2086 patients with BD over four cross-sectional studies was 30.9% (95% CI 18.1-47.4%, I²  = 95.6%). Overall, concurrent lithium therapy predicted the lowest TEM rates. Inconsistent operational definitions of TEM were recorded, and the lack of information about age, sex, co-occurring anxiety, and other clinically relevant moderators precluded further stratification of the results.

CONCLUSIONS

Rates of TEM vary primarily depending on study setting, which is concordant with the high degree of heterogeneity of the included records. Forthcoming RCT studies should adopt consistent operational definitions of TEM and broaden the number of moderators, in order to contribute most effectively to the identification of clear-cut sub-phenotypes of BD and patient-tailored pharmacotherapy.

Duloxetine-mirtazapine combination in depressive illness: The case for Limerick 'rocket fuel'

The use of complex psychopharmacological regimens is increasingly advocated in more difficult to treat depressive illness. The combination of venlafaxine with mirtazapine - 'California rocket fuel' is one such example involving an SNRI combined with a NaSSA. We describe two cases that highlight the potential usefulness of duloxetine used in combination with mirtazapine that also emphasise the danger of drug-induced hypomanic switching. This combination may have a specific role for carefully selected patients but caution is needed given the potential to induce profound alterations in mental state.

Time to relapse and remission of bipolar disorder: findings from a 1-year prospective study in Thailand

BACKGROUND AND METHODS

This study aimed to determine time to relapse and remission of mood episodes in Thai patients with bipolar disorder (BD). The Thai Bipolar Disorder Registry was a multicenter, prospective, naturalistic, observational study conducted in Thailand. Participants were adult inpatients or outpatients with Diagnostic and Statistical Manual of Mental Disorders bipolar disorder. The diagnosis of bipolar disorder, current psychiatric comorbidity, mood relapse, and mood remission were determined by using the Mini International Neuropsychiatric Interview. Relapse and remission were assessed every 2 months.

RESULTS

Of 424 BD participants, 404 (95.3%) were BD I, and 258 (60.8%) were female. At entry, 260 (61.3%) had recovered, and 49 (11.6%) were recovering. During 1-year follow-up (381.7 person-years), 92 participants (21.7%) had 119 relapses or 0.31 (95% confidence interval 0.25-0.35) episodes per person-year. Among 119 relapses, 58 (48.7%), 39 (32.7%), and 21 (17.6%) of them were depressive, hypomanic, and manic episodes, respectively. Using the Kaplan-Meier method, we found that 25% of the participants relapsed in 361 days. Of the 400 participants who reached remission, 113 (28.2%) had mood relapses. Of 173 mood events accountable for remission analysis, the median time to remission was 67.5 days (72.5 days for depressive episodes versus 58.0 days for manic episodes, log rank P = 0.014).

CONCLUSIONS

The 1-year relapse rate in Thai patients with BD was 21.7% or 0.31 episodes per person-year. About one-fifth of recovered patients had mood relapses within 371 days. On average, a mood episode would remit in 67.5 days.

The bipolar spectrum: a critical perspective

Recent suggestions to extend the boundaries of bipolar disorder to a broader spectrum lead to a concept of bipolarity different from that of classical psychiatry. It has been proposed that many patients with unipolar depression are actually bipolar and that many cases of substance abuse, personality disorders, and childhood behavioral disorders lie within the spectrum. However, since this expanded notion of bipolarity has been defined entirely on the basis of phenomenology, any expansion needs to meet broader criteria for validity. Bipolar spectrum disorders have a different phenomenology, family history, and course than classical bipolar disorders and do not respond in the same way to drugs. Until further research clarifies the boundaries of bipolarity, we should be conservative about extending its scope.

Neurotransmission and bipolar disorder: a systematic family-based association study

Neurotransmission pathways/systems have been proposed to be involved in the pathophysiology and treatment of bipolar disorder for over 40 years. In order to test the hypothesis that common variants of genes in one or more of five neurotransmission systems confer risk for bipolar disorder, we analyzed 1,005 tag single nucleotide polymorphisms in 90 genes from dopaminergic, serotonergic, noradrenergic, GABAergic, and glutamatergic neurotransmitter systems in 101 trios and 203 quads from Caucasian bipolar families. Our sample has 80% power to detect ORs >or= 1.82 and >or=1.57 for minor allele frequencies of 0.1 and 0.5, respectively. Nominally significant allelic and haplotypic associations were found for genes from each neurotransmission system, with several reaching gene-wide significance (allelic: GRIA1, GRIN2D, and QDPR; haplotypic: GRIN2C, QDPR, and SLC6A3). However, none of these associations survived correction for multiple testing in an individual system, or in all systems considered together. Significant single nucleotide polymorphism associations were not found with sub-phenotypes (alcoholism, psychosis, substance abuse, and suicide attempts) or significant gene-gene interactions. These results suggest that, within the detectable odds ratios of this study, common variants of the selected genes in the five neurotransmission systems do not play major roles in influencing the risk for bipolar disorder or comorbid sub-phenotypes.

Neurocognitive profiles in bipolar I and bipolar II disorder: differences in pattern and magnitude of dysfunction

OBJECTIVES

Studies on neurocognitive functioning in bipolar disorder, reporting deficits in memory, attention, and executive functioning, have primarily focused on bipolar I disorder. The aim of this study was to examine whether patients with bipolar I and bipolar II disorder have different neurocognitive profiles.

METHODS

Forty-two patients with bipolar I disorder, 31 patients with bipolar II and 124 healthy controls, from a large ongoing study on psychotic disorders, were included. Neurocognitive function was measured with a comprehensive neuropsychological test battery.

RESULTS

The bipolar I group performed significantly poorer than the healthy control group and the bipolar II group on all measures of memory. Compared with the control group, the bipolar I group also had significantly reduced performance on most measures of attention and executive functioning, while the bipolar II group only had a significantly reduced performance on a subset of these measures. On average, 24% of the bipolar I group had clinically significant cognitive impairment (< or =1.5 SD below the control group mean) across measures, compared with 13% of the bipolar II group.

CONCLUSIONS

Patients with bipolar I and bipolar II disorder in this study have different neurocognitive profiles. Bipolar I patients have more widespread cognitive dysfunction both in pattern and magnitude, and a higher proportion has clinically significant cognitive impairments compared with patients with bipolar II. This may suggest neurobiological differences between the two bipolar subgroups.

Bipolar II disorder: arguments for and against a distinct diagnostic entity

OBJECTIVE

As a commitment to the International Society for Bipolar Disorders (ISBD), a Task Force was developed to investigate the diagnostic value of bipolar II disorder.

METHODS

Task Force members worked jointly reviewing all relevant literature (original articles, reviews, letters, book chapters and congress presentations) that included 'bipolar II disorder' and/or 'hypomania' as key words.

RESULTS

Bipolar II disorder appears to be a reasonably valid and reliable diagnostic category yet often underdiagnosed or misdiagnosed as unipolar disorder or personality disorder. Moreover, it is officially recognized as a mental disorder in DSM-IV-TR but not in ICD-10, and many clinicians still regard it as a milder form of manic-depressive illness, despite data supporting high morbidity and mortality rates. In fact, bipolar II may be the most prevalent bipolar phenotype, although current diagnostic boundaries are seen as quite restrictive concerning the required duration for hypomania (4 days), the exclusion of hypomanic episodes potentially triggered by antidepressants and other substances, and the negligence of hypomanic mixed states. The course of bipolar II disorder is characterized by depressive predominant polarity, and its treatment is still controversial and poorly evidence-based.

CONCLUSIONS

Bipolar II disorder is supported as a distinct category within mood disorders, but the definition and boundaries deserve a greater clarification in the DSM-V and ICD-11.

Genome-wide scan of bipolar II disorder

OBJECTIVE

Bipolar disorder (BD) II is characterized by recurrent hypomanic and depressive episodes and has been somewhat of a controversial diagnosis since its description in the 1970s. Clinical opinions notwithstanding, the biological validity of BD II was supported in a genetic study of 58 multiplex bipolar families wherein the statistical evidence for linkage derived from BD II sibling-pairs sharing marker alleles on chromosome 18q. The BD II phenotype alone has never been studied in a genome-wide scan analysis in the current or other bipolar family samples. We have performed genome-wide non-parametric analysis on 74 bipolar pedigrees using only the BD II phenotype as affection model.

METHODS

This sample consists of the 65 pedigrees previously reported and 9 additional novel pedigrees that had BD II exclusively, as the affected phenotype. In the entire sample, there were 146 all possible relative-pairs. Analysis was performed using the non-parametric method in GENEHUNTER, with the 'ALL' option that computes linkage scores in all individuals in a pedigree simultaneously.

RESULTS

The current analyses supported the previous finding on chromosome 18q21. In addition a peak with a non-parametric LOD (NPL) of 2.07 occurred between D9S915 and D9S2157, located on 9q34. Analysis of the nine BD II families alone identified peaks on 9p13 and 9q33, with NPL scores of 3.20 and 2.09, respectively. There was no evidence at 18q21 in these nine families.

CONCLUSIONS

This suggests that there may be substantial differences in the etiology of BD in families that have BD II exclusively as the diagnosis.

Cross validation with the mood disorder questionnaire (MDQ) of an instrument for the detection of hypomania in Spanish: the 32 item hypomania symptom check list (HCL-32)

BACKGROUND

The detection and diagnosis of present or past hypomanic episodes is of key importance for the differential diagnosis between depressive disorders and type II bipolar disorder. However, there are few instruments available to satisfactorily screen for the latter condition. The Hypomania Symptom Checklist-32 (HCL-32) is a self-applied questionnaire with 32 hypomania items and 8 severity and functional impact items which is being developed in several European countries for this purpose. Our aim was to develop and validate the psychometric properties of the HCL-32 scale in Spain in patients with bipolar disorder and to compare its properties with other instruments available for the detection of bipolar II disorder.

METHODS

Patients were selected from 15 psychiatric outpatient departments, diagnosed with type I or type II bipolar disorder (BDI and BDII) and unipolar major depression (MD) according to DSM-IV-TR criteria. A control group of healthy subjects (HS) was likewise assessed. The patient selection criteria included a well-established diagnosis and a stable disorder and pharmacological treatment. The HCL-32 was administered to 237 subjects distributed among the above groups, on two occasions four weeks apart. We analysed the internal consistency, test-retest reliability and discriminative capacity of the HCL-32.

RESULTS

The internal consistency of the Spanish version of the HCL-32, evaluated by Cronbach's alpha, was 0.94. Mean of affirmative questions by group were 21.2 (SD 5.8) for BDI, 19.3 (SD 6.2) for BDII, 8.6 (SD 6.6) for MD and 6.6 (SD 6.1) for HS, with statistically significant differences between them (Kruskal-Wallis test, p<0.001). Concurrent validity using the diagnosis variable was 0.72. Test-retest reliability was 0.90. We analysed the best cut-off point by means of a ROC curve analysis; for 14 affirmative responses, a sensitivity of 0.85 95%CI (0.78, 0.91) and specificity of 0.79, 95%CI (0.72, 0.87) were obtained. The positive and negative probability ratios were 4.1 and 5.3 (1/0.19 respectively). HCL-32 shows a dual factor structure of items, one as an energy-activity factor and another one as a factor involving items related to disinhibition and problems with self-control and attention.

LIMITATIONS

The sample size of bipolar patients (particularly type BDII) should be increased in further studies.

CONCLUSIONS

The Spanish version of the HCL-32 has good psychometric properties and sufficient sensitivity and specificity, detecting 8 out of every 10 patients with BD. The HCL-32 is a useful screening tool of patients with bipolar disorder in clinical settings. In its present form it adequately discriminates between bipolar and unipolar or healthy subjects, but not between BD I and BII.

Disability associated with mood states and comparator conditions: application of the Life Skills Profile measure of disability

OBJECTIVE

To quantify the comparative level of disability experienced by those with mania and depression by contrasting against levels of disability experienced by those with schizophrenia, anxiety disorder and drug and alcohol dependence.

METHODS

Disability data, measured by use of an abbreviated version of the Life Skills Profile, were collected from an Australian national survey assessing more than 20,000 episodes of care, involving in-patients and out-patients.

RESULTS

Those with a diagnosis of mania rated as having higher levels of disability than those with depression and somewhat lower levels of disability than those with schizophrenia in the 3 months prior to assessment.

DISCUSSION

Such data from a large national survey underline the increasingly recognized reality that those experiencing manic episodes have high levels of associated disability, and that management interventions are required that address the impact of impaired functioning as well as acute episodes.

How low do we go? Is duration of a 'high' integral to the definition of bipolar disorder?

OBJECTIVE

There has been considerable debate about the diagnostic rules for bipolar II disorder, particularly the 4-day duration criteria for hypomanic episodes. This study examined whether highs lasting minutes or hours differed from longer highs in terms of clinical features and symptom severity. It also examined whether duration of highs predicted bipolar disorder being diagnosed.

METHOD

A total of 518 subjects with significant episodes of depression and 'highs' completed a web-based self-report questionnaire. Those who reported their longest highs lasting minutes or hours were compared with those who reported longer durations of highs on a range of clinical variables and measures of symptom severity.

RESULTS

Subjects whose highs lasted minutes or hours reported clinical features and severity of symptoms similar to those whose highs lasted 3-7 days. However, the odds of being diagnosed with bipolar disorder for those with highs lasting 3-7 days were almost three times higher than for those whose highs lasted minutes or hours.

CONCLUSION

The 4-day DSM-IV minimum-duration criteria for hypomania may lead to failure to diagnose subjects with brief highs who have true bipolar disorder and thus should be reconsidered.

Distinguishing bipolar and unipolar disorders: an isomer model

BACKGROUND

As division between unipolar and bipolar disorders can be problematic, we sought to develop a self-report questionnaire of mood 'highs' that would both distinguish true Bipolar Disorder from any elevated mood states in unipolar depression and sharpen the distinction between Bipolar I and II conditions.

METHOD

A 46-item questionnaire was developed and completed by 157 out-patients presenting with a major depressive episode, and clinically diagnosed as having either Bipolar I (BP-I), Bipolar II (BP-II) or Unipolar (UP) depression, although DSM-IV duration criteria for BP-I and BP-II were not imposed.

RESULTS

Factor analyses identified four key constructs to mood 'highs', while additional analyses refined the questionnaire to 27 items. The refined measure was highly accurate in distinguishing composite Bipolar (BP-I and BP-II) from UP subjects (AUC = 0.93, sensitivity = 81%; specificity = 98%, positive predictive value = 0.95). Questionnaire scores were similar for BP-I and BP-II subjects, raising the possibility that the core mood state differs little in severity across the two expressions, and that their distinction allows an alternative model that weights the presence or absence of psychotic features.

CONCLUSIONS

Our study advances understanding of boundary distinctions between bipolar and unipolar mood disorders, and between BP-I and BP-II conditions, and allows consideration of a model distinguishing BP-I from BP-II by the presence of psychotic features only. The described model is the mirror image of a hierarchical structural model for conceptualizing psychotic and melancholic depression, allowing an 'isomer model' for linking the mood swing states.

SSRIs as mood stabilizers for Bipolar II Disorder? A proof of concept study

BACKGROUND

We have previously observed that prescription of some antidepressant class drugs (particularly the SSRIs) is associated with attenuation of the number, duration and severity of both high and low mood states in those with Bipolar II Disorder. We examined whether SSRIs are a mood stabilizer for Bipolar II Disorder.

METHOD

We report a randomized, double-blind, placebo-controlled cross-over study lasting 9 months in a sample of 10 patients who had not had previous treatment with any antidepressant, antipsychotic or mood stabilizer drug.

RESULTS

Treatment with the SSRI led to a significant reduction in depression severity, percentage of days depressed or high, and percentage of days impaired, when compared with placebo. There was no indication that the SSRI led to a worsening of illness course.

LIMITATIONS

Given the small sample size and a weighting to those with a rapid cycling condition, replication with a larger and more heterogeneous sample of those with Bipolar Disorder is required.

CONCLUSIONS

This proof of concept study finds preliminary support for the potential utility of SSRIs in managing Bipolar II Disorder, with clear improvements in depression and impairment and some suggested benefit for hypomania.