Rating scales in bipolar disorder

Predicting remission after acute phase pharmacotherapy in patients with bipolar I depression: A machine learning approach with cross-trial and cross-drug replication

OBJECTIVES

Interpatient variability in bipolar I depression (BP-D) symptoms challenges the ability to predict pharmacotherapeutic outcomes. A machine learning workflow was developed to predict remission after 8 weeks of pharmacotherapy (total score of ≤8 on the Montgomery Åsberg Depression Rating Scale [MADRS]).

METHODS

Supervised machine learning models were trained on data from BP-D patients treated with olanzapine (N = 168) and were externally validated on patients treated with olanzapine/fluoxetine combination (OFC; N = 131) and lamotrigine (LTG; N = 126). Top predictors were used to develop a prognosis rule informing how many symptoms should change and by how much within 4 weeks to increase the odds of achieving remission.

RESULTS

An AUC of 0.76 (NIR:0.59; p = 0.17) was established to predict remission in olanzapine-treated subjects. These trained models achieved AUCs of 0.70 with OFC (NIR:0.52; p < 0.03) and 0.73 with LTG (NIR:0.52; p < 0.003), demonstrating external replication of prediction performance. Week-4 changes in four MADRS symptoms (reported sadness, reduced sleep, reduced appetite, and concentration difficulties) were top predictors of remission. Across all pharmacotherapies, three or more of these symptoms needed to improve by ≥2 points at Week-4 to have a 65% chance of achieving remission at 8 weeks (OR: 3.74, 95% CI: 2.45-5.76; p < 9.3E-11).

CONCLUSION

Machine learning strategies achieved cross-trial and cross-drug replication in predicting remission after 8 weeks of pharmacotherapy for BP-D. Interpretable prognoses rules required only a limited number of depressive symptoms, providing a promising foundation for developing simple quantitative decision aids that may, in the future, serve as companions to clinical judgment at the point of care.

Functional near-infrared spectroscopy during the verbal fluency task of English-Speaking adults with mood disorders: A preliminary study

Functional near-infrared spectroscopy (fNIRS) provides a direct and objective assessment of cerebral cortex function. It may be used to determine neurophysiological differences between psychiatric disorders with overlapping symptoms, such as major depressive disorder (MDD) and bipolar disorder (BD). Therefore, this preliminary study aimed to compare fNIRS signals during the verbal fluency task (VFT) of English-speaking healthy controls (HC), patients with MDD and patients with BD. Fifteen HCs, 15 patients with MDD and 15 patients with BD were recruited. Groups were matched for age, gender, ethnicity and education. Relative oxy-haemoglobin and deoxy-haemoglobin changes in the frontotemporal cortex was monitored with a 52-channel fNIRS system. Integral values of the frontal and temporal regions were derived as a measure cortical haemodynamic response magnitude. Both patient groups had lower frontal and temporal region integral values than HCs, and patients with MDD had lower frontal region integral value than patients with BD. Moreover, patients could be differentiated from HCs using the frontal and temporal integral values, and patient groups could be differentiated using the frontal region integral values. VFT performance, clinical history and symptom severity were not associated with integral values. These results suggest that prefrontal cortex haemodynamic dysfunction occurs in mood disorders, and it is more extensive in MDD than BD. The fNIRS-VFT paradigm may be a potential tool for differentiating MDD from BD in clinical settings, and these findings need to be verified in a larger sample of English-speaking patients with mood disorders.

A Systematic Review of the Clinical Use of Gabapentin and Pregabalin in Bipolar Disorder

Despite its prevalence and disease burden, several chasms still exist with regard to the pharmacotherapy of bipolar disorder (BD). Polypharmacy is commonly encountered as a significant proportion of patients remain symptomatic, and the management of the depressive phase of the illness is a particular challenge. Gabapentin and pregabalin have often been prescribed off-label in spite of a paucity of evidence and clinical practice guidelines to support its use. This systematic review aimed to synthesize the available human clinical trials and inform evidence-based pharmacological approaches to BD management. A total of six randomized, controlled trials (RCTs) and 13 open-label trials involving the use of gabapentin and pregabalin in BD patients were reviewed. Overall, the studies show that gabapentin and its related drug pregabalin do not have significant clinical efficacy as either monotherapy or adjunctive therapy for BD. Gabapentin and pregabalin are probably ineffective for acute mania based on the findings of RCT, with only small open-label trials to support its potential adjunctive role. However, its effects on the long-term outcomes of BD remain to be elucidated. The evidence base was significantly limited by the generally small sample sizes and the trials also had heterogeneous designs and generally high risk of bias.

Terminology and assessment tools of psychosis: A systematic narrative review

AIM

Phenomena within the psychosis continuum that varies in frequency/duration/intensity have been increasingly identified. Different terms describe these phenomena, however there is no standardization within the terminology. This review evaluated the definitions and assessment tools of seven terms - (i) 'psychotic experiences'; (ii) 'psychotic-like experiences'; (iii) 'psychotic-like symptoms'; (iv) 'attenuated psychotic symptoms'; (v) 'prodromal psychotic symptoms'; (vi) 'psychotic symptomatology'; and (vii) 'psychotic symptoms'.

METHODS

EMBASE, MEDLINE, and CINAHL were searched during February-March 2019. Inclusion criteria included 1989-2019, full text, human, and English. Papers with no explicit definition or assessment tool, duplicates, conference abstracts, systematic reviews, meta-analyses, or no access were excluded.

RESULTS

A total of 2238 papers were identified and of these, 627 were included. Definitions and assessment tools varied, but some trends were found. Psychotic experiences and psychotic-like experiences were transient and mild, found in the general population and those at-risk. Psychotic-like symptoms were subthreshold and among at-risk populations and non-psychotic mental disorders. Attenuated psychotic symptoms were subthreshold but associated with distress, risk, and help-seeking. Prodromal psychotic symptoms referred to the prodrome of psychotic disorders. Psychotic symptomatology included delusions and hallucinations within psychotic disorders. Psychotic symptoms was the broadest term, encompassing a range of populations but most commonly involving hallucinations, delusions, thought disorder, and disorganization.

DISCUSSION

A model for conceptualizing the required terms is proposed and future directions needed to advance this field of research are discussed.

Defining cognitive and functional profiles in schizophrenia and affective disorders

BACKGROUND

Neurocognitive dysfunction is a common symptom of various major psychiatric disorders, including schizophrenia, major depressive disorder (MDD), and bipolar I disorder (BD). In this study, we investigated whether cognitive profiles and daily skill functioning could effectively differentiate between patients with schizophrenia, MDD, and BD.

METHOD

In this cross-sectional study, we recruited a total of 63 patients with schizophrenia, 55 patients with MDD, 43 patients with BD, and 92 healthy control subjects. We evaluated participants' cognitive functions and functional capacity using the Brief Assessment of Cognition in Schizophrenia (BACS) and the UCSD Performance-based Skills Assessment, Brief Version (UPSA-B), respectively. Multivariate analysis of covariance was then adopted to determine inter-group differences in BACS and UPSA-B performance.

RESULTS

The BACS was capable of differentiating patients with a major psychiatric disorder (schizophrenia, MDD, and BD) from healthy subjects. Furthermore, schizophrenia patients had poorer motor speed performance than patients with affective disorders. The UPSA-B, particularly the financial portion, was able to distinguish schizophrenia patients from other groups. However, we did not observe any differences in UPSA-B performance between patients with mood disorders and the healthy controls. No significant difference between patients with BD and those with MDD were observed in either cognitive function or in functional capacity. The performances of the BACS and the UPSA-B were positively correlated, particularly in the MDD group.

CONCLUSION

Considering overall performance, the BACS and the UPSA-B characterize different endophenotyping profiles in the aforementioned four participant groups. Therefore, the results support the need for comprehensive assessments that target both cognitive function and functional capacity for patients with major psychiatric disorders.

Systematic Review of Symptom Assessment Measures for Use in Measurement-Based Care of Bipolar Disorders

OBJECTIVE

Utilization of measurement-based care (MBC) for bipolar disorders is limited, in part because of uncertainty regarding the utility of available measures. The aim of this study was to synthesize the literature on patient-reported and clinician-observed measures of symptoms of bipolar disorder and the potential use of these measures in MBC.

METHODS

A systematic review of multiple databases (PubMed, Embase, PsycINFO, Cochrane Library, and other gray literature) was conducted in June 2017 to identify validated measures. Data on the psychometric properties of each measure were extracted and used to assess the measure's clinical utility on the basis of established guidelines.

RESULTS

Twenty-eight unique measures were identified in 39 studies, including four patient-reported and six clinician-observed measures assessing manic symptoms, three patient-reported and five clinician-observed measures of depressive symptoms, and six patient-reported and four clinician-observed measures of both symptom types. Patient-reported measures with the highest clinical utility included the Altman Self-Rating Mania Scale for assessment of manic symptoms, the Quick Inventory of Depressive Symptomatology-Self Report (QIDS-SR) (depressive symptoms), and the Internal State Scale (both types). Highly rated clinician (C)-observed scales were the Bech-Rafaelsen Mania Rating Scale (mania), the QIDS-C (depressive symptoms), and the Bipolar Inventory of Symptoms Scale (both types).

CONCLUSIONS

Suitable choices are available for MBC of bipolar disorders. The choice of a measure could be informed by clinical utility score and may also depend on how clinicians or practices weigh each category of the clinical utility scale and on the clinical setting and presenting problem.

An item response theory evaluation of the young mania rating scale and the montgomery-asberg depression rating scale in the systematic treatment enhancement program for bipolar disorder (STEP-BD)

BACKGROUND

The Young Mania Rating Scale (YMRS) and Montgomery-Asberg Depression Rating Scale (MADRS) are among the most widely used outcome measures for clinical trials of medications for Bipolar Disorder (BD). Nonetheless, very few studies have examined the measurement characteristics of the YMRS and MADRS in individuals with BD using modern psychometric methods. The present study evaluated the YMRS and MADRS in the Systematic Treatment Enhancement Program for BD (STEP-BD) study using Item Response Theory (IRT).

METHODS

Baseline data from 3716 STEP-BD participants were available for the present analysis. The Graded Response Model (GRM) was fit separately to YMRS and MADRS item responses. Differential item functioning (DIF) was examined by regressing a variety of clinically relevant covariates (e.g., sex, substance dependence) on all test items and on the latent symptom severity dimension, within each scale.

RESULTS

Both scales: 1) contained several items that provided little or no psychometric information, 2) were inefficient, in that the majority of item response categories did not provide incremental psychometric information, 3) poorly measured participants outside of a narrow band of severity, 4) evidenced DIF for nearly all items, suggesting that item responses were, in part, determined by factors other than symptom severity.

LIMITATIONS

Limited to outpatients; DIF analysis only sensitive to certain forms of DIF.

CONCLUSIONS

The present study provides evidence for significant measurement problems involving the YMRS and MADRS. More work is needed to refine these measures and/or develop suitable alternative measures of BD symptomatology for clinical trials research.

Altered cardiorespiratory coupling in young male adults with excessive online gaming

INTRODUCTION

This study aimed to investigate changes in heart rate variability and cardiorespiratory coupling in male college students with problematic Internet use (PIU) excessive gaming type during action video game play to assess the relationship between PIU tendency and central autonomic regulation.

METHOD

Electrocardiograms and respiration were simultaneously recorded from 22 male participants with excessive online gaming and 22 controls during action video game play. Sample entropy (SampEn) was computed to assess autonomic regularity, and cross-SampEn was calculated to quantify autonomic coordination.

RESULTS

During video game play, reduced cardiorespiratory coupling (CRC) was observed in individuals with PIU excessive gaming type compared with controls, implicating central autonomic dysregulation. The PIU tendency was associated with the severity of autonomic dysregulation.

CONCLUSION

These findings indicate impaired CRC in PIU excessive gaming type, which may reflect alterations of central inhibitory control over autonomic responses to pleasurable online stimuli.

Differential diagnosis, comorbidity, and treatment of attention-deficit/hyperactivity disorder in relation to bipolar disorder or borderline personality disorder in adults

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) in adults can resemble, and often co-occurs with, bipolar disorder (BD) and borderline personality disorder (BPD). This can lead to mistaken diagnoses and ineffective treatment, resulting in potentially serious adverse consequences. All three conditions can substantially impair well-being and functioning, while BD and BPD are associated with suicidality.

OBJECTIVES

To update clinicians on the overlap and differences in the symptomatology of ADHD versus BD and BPD in adults; differential diagnosis of ADHD from BD and BPD in adults; and diagnosis and treatment of adults with comorbid ADHD-BD or ADHD-BPD.

METHODS

We searched four databases, referred to the new Diagnostic and Statistical Manual of Mental Disorders, 5th edition, used other relevant literature, and referred to our own clinical experience.

RESULTS

ADHD coexists in ∼20% of adults with BD or BPD. BD is episodic, with periods of normal mood although not necessarily function. In patients with comorbid ADHD-BD, ADHD symptoms are apparent between BD episodes. BPD and ADHD are associated with chronic trait-like symptoms and impairments. Overlapping symptoms of BPD and ADHD include impulsivity and emotional dysregulation. Symptoms of BPD but not ADHD include frantically avoiding real/imagined abandonment, suicidal behavior, self-harm, chronic feelings of emptiness, and stress-related paranoia/severe dissociation. Consensus expert opinion recommends that BD episodes should be treated first in patients with comorbid ADHD, and these patients may need treatment in stages (e.g. mood stabilizer[s], then a stimulant/atomoxetine). Data is scarce and mixed about whether stimulants or atomoxetine exacerbate mania in comorbid ADHD-BD. BPD is primarily treated with psychotherapy. Principles of dialectical behavioral treatment for BPD may successfully treat ADHD in adults, as an adjunct to medication. No fully evidence-based pharmacotherapy exists for core BPD symptoms, although some medications may be effective for individual symptom domains, e.g. impulsivity (shared by ADHD and BPD). In our experience, treatment of ADHD should be considered when treating comorbid personality disorders.

CONCLUSIONS

It is important to accurately diagnose ADHD, BD, and BPD to ensure correct targeting of treatments and improvements in patient outcomes. However, there is a shortage of data about treatment of adults with ADHD and comorbid BD or BPD.

Saving time and money: a validation of the self ratings on the prospective NIMH Life-Chart Method (NIMH-LCM)

BACKGROUND

Careful observation of the longitudinal course of bipolar disorders is pivotal to finding optimal treatments and improving outcome. A useful tool is the daily prospective Life-Chart Method, developed by the National Institute of Mental Health. However, it remains unclear whether the patient version is as valid as the clinician version.

METHODS

We compared the patient-rated version of the Lifechart (LC-self) with the Young-Mania-Rating Scale (YMRS), Inventory of Depressive Symptoms-Clinician version (IDS-C), and Clinical Global Impression-Bipolar version (CGI-BP) in 108 bipolar I and II patients who participated in the Naturalistic Follow-up Study (NFS) of the German centres of the Bipolar Collaborative Network (BCN; formerly Stanley Foundation Bipolar Network). For statistical evaluation, levels of severity of mood states on the Lifechart were transformed numerically and comparison with affective scales was performed using chi-square and t tests. For testing correlations Pearson´s coefficient was calculated.

RESULTS

Ratings for depression of LC-self and total scores of IDS-C were found to be highly correlated (Pearson coefficient r = -.718; p < .001), whilst the correlation of ratings for mania with YMRS compared to LC-self were slightly less robust (Pearson coefficient r = .491; p = .001). These results were confirmed by good correlations between the CGI-BP IA (mania), IB (depression) and IC (overall mood state) and the LC-self ratings (Pearson coefficient r = .488, r = .721 and r = .65, respectively; all p < .001).

CONCLUSIONS

The LC-self shows a significant correlation and good concordance with standard cross sectional affective rating scales, suggesting that the LC-self is a valid and time and money saving alternative to the clinician-rated version which should be incorporated in future clinical research in bipolar disorder. Generalizability of the results is limited by the selection of highly motivated patients in specialized bipolar centres and by the open design of the study.

Role of omega-3 fatty acids in the treatment of depressive disorders: a comprehensive meta-analysis of randomized clinical trials

Background

Despite omega-3 polyunsaturated fatty acids (PUFA) supplementation in depressed patients have been suggested to improve depressive symptomatology, previous findings are not univocal.

Objectives

To conduct an updated meta-analysis of randomized controlled trials (RCTs) of omega-3 PUFA treatment of depressive disorders, taking into account the clinical differences among patients included in the studies.

Methods

A search on MEDLINE, EMBASE, PsycInfo, and the Cochrane Database of RCTs using omega-3 PUFA on patients with depressive symptoms published up to August 2013 was performed. Standardized mean difference in clinical measure of depression severity was primary outcome. Type of omega-3 used (particularly eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) and omega-3 as mono- or adjuvant therapy was also examined. Meta-regression analyses assessed the effects of study size, baseline depression severity, trial duration, dose of omega-3, and age of patients.

Results

Meta-analysis of 11 and 8 trials conducted respectively on patients with a DSM-defined diagnosis of major depressive disorder (MDD) and patients with depressive symptomatology but no diagnosis of MDD demonstrated significant clinical benefit of omega-3 PUFA treatment compared to placebo (standardized difference in random-effects model 0.56 SD [95% CI: 0.20, 0.92] and 0.22 SD [95% CI: 0.01, 0.43], respectively; pooled analysis was 0.38 SD [95% CI: 0.18, 0.59]). Use of mainly EPA within the preparation, rather than DHA, influenced final clinical efficacy. Significant clinical efficacy had the use of omega-3 PUFA as adjuvant rather than mono-therapy. No relation between efficacy and study size, baseline depression severity, trial duration, age of patients, and study quality was found. Omega-3 PUFA resulted effective in RCTs on patients with bipolar disorder, whereas no evidence was found for those exploring their efficacy on depressive symptoms in young populations, perinatal depression, primary disease other than depression and healthy subjects.

Conclusions

The use of omega-3 PUFA is effective in patients with diagnosis of MDD and on depressive patients without diagnosis of MDD.

The reliability of self-assessment of affective state in different phases of bipolar disorder

Some studies have indicated that the capacity of self-assessment of affective state is more compromised during mania than during depression. In the present study, we investigated whether the reliability of self-assessment in bipolar disorder varies as a function of actual affective state (i.e., euthymia, mania, or depression). Sixty-five patients with a diagnosis of type I and type II bipolar disorder were evaluated with regard to the occurrence of an affective syndrome using the Clinical Global Impressions Scale for use in bipolar illness, the Positive and Negative Syndrome Scale, and the Global Assessment of Functioning scale. In parallel, we applied the Analog Visual Mood Scale, a self-assessment tool to evaluate mood changes. The same individual prospectively completed the self-assessment scale in different affective states. During depression, the patients' evaluation was significantly different from when they were in manic or euthymic mood states. However, when in mania, the patients evaluated their mood state similarly to when they were euthymic. The bipolar patients in mania but not in depression did not reliably evaluate themselves with regard to their affective state.

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.

Alexithymia and severe psychopathology: a study on psychiatric inpatients

BACKGROUND

The influence of severe psychopathology on alexithymic features has been poorly studied. This study aimed at investigating whether alexithymia is affected by the presence of psychosis and the severity of psychopathology.

SAMPLING AND METHODS

199 consecutive adult psychiatric inpatients, 60 of whom received a Structured Clinical Interview for DSM-IV Axis I diagnosis of psychotic disorder, were administered the 20-item Toronto Alexithymia Scale (TAS-20) and the 24-item Brief Psychiatric Rating Scale (BPRS). A random sample of 50 patients was reassessed at discharge. For all analyses, the Holm-Bonferroni correction was applied when appropriate to account for multiple testing.

RESULTS

The TAS-20 showed good internal consistency, acceptable relative stability, and good absolute stability both in patients with and without a psychotic disorder. Internal consistency and relative stability were higher in nonpsychotic than in psychotic patients. Mean TAS-20 score at admission did not differ between psychotic and nonpsychotic patients, and the TAS-20 score showed only a nonsignificant correlation (rho = 0.26) with BPRS score. Alexithymia at discharge was mostly explained (60%) by alexithymia at admission, while it was only modestly explained (4%) by BPRS scores at admission and discharge, with the latter being the only significant predictor. Changes in BPRS scores between admission and discharge explained a nonsignificant proportion (16%) of changes in TAS-20 scores and a moderate (21%) proportion of changes in difficulty identifying feelings.

CONCLUSION

Despite some limitations, these findings suggest that the severity of psychopathology and the presence of a psychotic disorder only modestly influence alexithymic characteristics, and that the TAS-20 may provide a reliable assessment of alexithymia in patients with severe psychopathology, except the most severely impaired ones.

Clinical utility of screening for clinical depression and bipolar disorder

PURPOSE OF REVIEW

Screening for clinical depression and bipolar disorder remains controversial. Screening is usually based on finding discriminating symptoms, but not all tools perform equally well. Clinicians should be able to assess the clinical utility of screening tests as well as their accuracy and acceptability.

RECENT FINDINGS

Screening for depression using the Patient Health Questionnaire (PHQ) has been extensively examined. Four main versions of scoring the PHQ exist. The two-item PHQ2, the nine-item PHQ9, the PHQ DSM-IV algorithm, and the two-step PHQ2 then PHQ9. Recent results suggest that the PHQ9 is more accurate than the PHQ2, and that the algorithm scoring method is preferred to the linear cut-off score. The two-step procedure has promise, but it has not been adequately tested. Two screening questions may be a useful compromise in medical settings, as they take less than 2 min, but about a quarter of patients do not receive screening even when implemented systematically. Alternative customized questionnaires have been developed in medical settings such as the Depression Screening in Parkinson's Disease DESPAR and Neurological Disorders Depression Inventory for Epilepsy (NDDI-E). Screening for bipolar disorders is an even greater challenge than screening for unipolar depression. Screening in primary care and the community has low positive predictive value. Screening in high-risk samples, such as those with known depression is somewhat more successful, but not yet sufficiently accurate to be used alone.

SUMMARY

Screening for depression can bring added value to routine unassisted recognition, but only if followed by good-quality treatment. Screening for bipolar disorder is not yet sufficiently accurate to be used reliably in clinical practice.

Diagnosis and monitoring of bipolar disorder in general practice

General practitioners are often consulted for first presentations of bipolar disorder and are well placed to coordinate patient care. They can assist with early identification of bipolar disorder and monitoring for manic and depressive episodes. Delayed and incorrect diagnoses are common in bipolar disorder, and unipolar depression is a frequent misdiagnosis. Characteristics that can be used to distinguish bipolar I depression from unipolar depression (when no clear prior manic episodes are evident) include the course of illness, symptoms, mental state signs and family history. Manic episodes can be caused by poor adherence to medication, substance misuse, antidepressants and stressful events, and are often preceded by early warning signs. Early warning signs are less commonly observed for depressive episodes. Daily mood charts are useful for providing an overview of patient progress and for identifying and managing early warning signs. Families and carers can also play an active role in supporting patients with bipolar disorder.

Exploring clinical characteristics of bipolar depression: internal structure of the bipolar depression rating scale

OBJECTIVE

Due to its pleomorphic phenomenology, the clinical features of bipolar depression are difficult to assess. The objective of the present study was therefore to explore the internal structure of the Bipolar Depression Rating Scale (BDRS) in terms of the phenomenological characteristics of bipolar depression.

METHODS

Sixty patients with DSM-IV bipolar depression completed the BDRS, depression and excitement subscales of the Positive and Negative Syndrome Scale (PANSS-D and PANSS-E), 17-item Hamilton Depression Rating Scale, Montgomery-Asberg Depression Rating Scale, Young Mania Rating Scale (YMRS), and the Drug-Induced Extrapyramidal Symptoms Scale. The internal structure of the BDRS was explored through hierarchical cluster analysis (HCA) using Ward's method and multidimensional scaling (MDS).

RESULTS

From 20-item BDRS data, the HCA yielded two symptom clusters. The first cluster included 12 items of conventional depressive symptoms. The second cluster included eight items of mixed symptoms. The MDS identified a depressive-mixed dimension. The depressive symptom cluster showed a more cohesive and conglomerate cluster structure on the MDS map compared to the mixed symptom cluster. After controlling for the effects of treatment-emergent extrapyramidal symptoms, strong positive correlations were observed between the BDRS and other depression rating scales, and the BDRS also weakly correlated with the YMRS and the PANSS-E.

CONCLUSIONS

The internal structure of BDRS appears to be sensitive to complex features of bipolar depression. Hence, the BDRS may have an advantage in evaluating clinical changes in patients with bipolar depression within the therapeutic process.

Bipolar disorder: emotional dysregulation and neuronal vulnerability

Bipolar disorder is clinically characterized by fluctuating affect, and neuropsychologically by impairment in executive functions. Such phenomena are consistent with the centrality of emotional dysregulation and impulsivity to bipolar disorder. They are also consistent with a key role for prefrontal-subcortical (striatal-thalamic) and associated limbic circuitry in its mediation. Furthermore, there is growing data on the cellular mechanisms contributing to neuronal vulnerability in this mediating circuitry.