Neurocognition in bipolar disorders—A closer look at comorbidities and medications

Cognitive functions in euthymic Egyptian patients with bipolar disorder: are they different from healthy controls?

BACKGROUND

There is marked interest to research neurocognitive functions in bipolar disorder during euthymia. Consequently we aimed to study cognitive functions in euthymic bipolar patients and factors affecting them.

METHODS

It is a cross sectional case-control study of 60 euthymic bipolar patients and 30 matched healthy controls. They were subjected to: Structured Clinical Interview for DSM-IV disorders, (SCID-I) to ascertain clinical diagnosis, Young Mania Rating Scale (YMRS), Hamilton Rating Scale for Depression (HRSD) to validate euthymia. Wechsler Adult Intelligence Scale (WAIS) for general intellectual abilities, Wechsler Memory Scale-Revised (WMS-R) for memory, Wisconsin Card Sorting Test (WCST) for executive functions, Continuous Performance Test (CPT) for attention and impulsivity, and an information sheet gathering patient data.

RESULTS

Bipolar patients had statistically significant lower mean IQ scores in all WAIS subscales (p=0.000), significantly lower memory abilities especially digit span and visual memory, higher impulsivity and inattention (p=0.000) but no significant difference in response time by CPT. They displayed significantly lower executive performance on WCST. Patients' years of education correlated positively with IQ. Hospital admission, number, type of episodes and total number of episodes affected memory functions. Hospital admission and number of hypomanic episodes correlated with attention and impulsivity. Previous hospitalization correlated with executive functions.

CONCLUSIONS

Euthymic bipolar patients exhibit cognitive deficits, which correlated with clinical variables as number, type of episodes and previous hospitalization, this knowledge could help minimize cognitive impairments for future patients.

LIMITATIONS

The small sample size, cross sectional design and lack of premorbid cognitive assessment limit generalization of findings.

Family history of a mood disorder indicates a more severe bipolar disorder

BACKGROUND

In the clinical setting, patients with bipolar disorder (BD) are often asked about potential family history (FH) of mood disorders. The aim of the present study was to examine differences between BD patients with FH of a mood disorder, and those without, on clinical, personality and social functioning characteristics, as well as on the symptomatic course of the disorder.

METHODS

Data was collected from the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD). For this report, we included 2600 patients, 1963 of those reported having a first-degree family member with a mood disorder, and 637 reported of no such FH. We investigated the impact of FH on socio-demographic, clinical, personality and quality of life variables, as well as on symptomatology during the first year of treatment.

RESULTS

Patients reporting FH of a mood disorder had an earlier age at onset of depression/mania, more phases, rapid cycling and more suicide attempts. Across different assessments, patients with FH showed consistently elevated depressive symptoms, such as lower concentration and energy, higher suicidal ideation, as well as increased racing thoughts and distractibility within the manic spectrum of symptoms. Further, the FH group had lower quality of life, higher neuroticism and higher personality disorder scores compared to patients without FH.

LIMITATIONS

Information on FH was obtained through the proband.

CONCLUSIONS

Overall, BD patients reporting FH of a mood disorder showed a worse clinical profile upon presentation for treatment and a more symptomatic course of the disorder.

Sex dependence of cognitive functions in bipolar disorder

The objective of the present study was to assess the performance of lithium treated euthymic bipolar patients in tests measuring spatial working memory (SWM), planning, and verbal fluency and to delineate the influence of gender on cognitive functioning. Fifty-nine euthymic bipolar patients, treated with lithium carbonate for at least 5 yr, were studied. Patients and controls underwent a neuropsychological assessment. Bipolar patients had significantly worse results than the healthy controls in the spatial memory and planning as well as verbal fluency tests. We detected a gender-related imbalance in the SWM results. Deficits in SWM were observed in male-only comparisons but not in female-only comparisons. The SWM scores were significantly poorer in male patients than in male controls. In female-only comparisons, female patients did not have significantly poorer SWM results in any category than their controls. Bipolar women scored worse in some other tests. The present study points to the different patterns of neuropsychological disturbances in female and male patients and suggests that sex-dependent differences should be taken into account in order to tailor the therapeutic intervention aimed at the improvement of cognitive functions.

Glycogen synthase kinase-3 inhibitors: Rescuers of cognitive impairments

Impairment of cognitive processes is a devastating outcome of many diseases, injuries, and drugs affecting the central nervous system (CNS). Most often, very little can be done by available therapeutic interventions to improve cognitive functions. Here we review evidence that inhibition of glycogen synthase kinase-3 (GSK3) ameliorates cognitive deficits in a wide variety of animal models of CNS diseases, including Alzheimer's disease, Fragile X syndrome, Down syndrome, Parkinson's disease, spinocerebellar ataxia type 1, traumatic brain injury, and others. GSK3 inhibitors also improve cognition following impairments caused by therapeutic interventions, such as cranial irradiation for brain tumors. These findings demonstrate that GSK3 inhibitors are able to ameliorate cognitive impairments caused by a diverse array of diseases, injury, and treatments. The improvements in impaired cognition instilled by administration of GSK3 inhibitors appear to involve a variety of different mechanisms, such as supporting long-term potentiation and diminishing long-term depression, promotion of neurogenesis, reduction of inflammation, and increasing a number of neuroprotective mechanisms. The potential for GSK3 inhibitors to repair cognitive deficits associated with many conditions warrants further investigation of their potential for therapeutic interventions, particularly considering the current dearth of treatments available to reduce loss of cognitive functions.

Facial emotion recognition and its correlation with executive functions in bipolar I patients and healthy controls

INTRODUCTION

The ability to recognize facial emotions is altered in patients with Bipolar Disorder (BD) during mood episodes and even in euthymia, while cognitive functioning is similarly impaired. This recognition is considered a fundamental skill for successful social interaction. However, it is unclear whether the ability to recognize facial emotions is correlated with the cognitive deficits observed in BD.

OBJECTIVE

The objective of this study was to evaluate Facial Emotion Recognition (FER) and its correlation with executive function (EF) in BD I patients during mania, depression and euthymia compared to healthy controls.

MATERIAL AND METHODS

A total of 110 patients with BD I, 18-40 years old were included (41 in manic episode; 31 in depressive episode and 38 euthymic). Patients were assessed for FER and EF (Wisconsin card sorting test - WCST), along with 96 healthy volunteers (18-40 years old) recruited from the University of São Paulo.

RESULTS

The results showed that BD I patients had lower FER performance compared to controls on fear subtests, happiness, the surprise test, and FER total scores. Moreover, BD I manic patients showed poorer performance for EF compared to controls. Six out of the seven variables of the WCST correlated with FER in both healthy controls and BD euthymic subjects but not in BD patients during mood episodes.

CONCLUSION

Cognitive deficits and difficulties recognizing facial emotions are present in all mood episodes in BD I patients, even during remission. Although FER is not considered a cognitive domain, these results suggest that, along with EF, it has a complementary function. Hence, further studies should investigate this issue in larger samples and verify whether these similarities also occur at a neurobiological level.

Neurocognitive impairments and quality of life in unemployed patients with remitted major depressive disorder

Quality of life (QOL) has been reported to be impaired in patients with major depressive disorder (MDD), even after remission according to symptom rating scales. Although a relationship between QOL and neurocognitive dysfunction has been reported during depressive episodes, little is known about this relationship in remitted MDD patients. The aim of the present study was to investigate the relationship between QOL and neurocognitive dysfunction in patients with remitted MDD while controlling for confounding factors. Forty-three remitted MDD patients were assessed with neuropsychological tests and QOL, which was measured by a short-form 36-item health survey. The neurocognitive performances of the patients were compared with those of 43 healthy controls. We next evaluated the relationships between neurocognitive impairments, clinical factors, and QOL. Remitted MDD patients had poorer neurocognitive performances than healthy controls for psychomotor speed, attention, and verbal memory. Residual depressive symptoms were strongly associated with QOL. Delayed verbal recall was associated with general health perceptions, which are part of the QOL assessment, even after the effects of the residual depressive symptoms were considered. The results may indicate that clinicians should try to detect neurocognitive dysfunctions that may interfere with QOL using neurocognitive assessments in their daily practice.

Antipsychotic medications and cognitive functioning in bipolar disorder: moderating effects of COMT Val108/158 Met genotype

BACKGROUND

There is a negative association between the use of antipsychotics and cognitive functioning in bipolar patients, which may be mediated by altered dopamine signaling in selected brain areas, and moderation thereof by genetic sequence variation such as COMT Val108/158Met. The interaction between antipsychotic drug use and the COMT Val108/158Met genotype on two-year cognitive functioning in bipolar patients was examined.

METHODS

Interaction between the COMT Val108/158Met and antipsychotics on a composite cognitive measure was examined in 51 bipolar patients who were assessed 12 times at two-monthly intervals over a period of two years (379 observations).

RESULTS

There was a significant negative effect of the interaction between antipsychotic medications and Val allele load on the composite cognitive measure in bipolar patients (p < 0.001).

CONCLUSIONS

The negative effects of antipsychotics on cognitive functioning in bipolar disorder may be moderated by the COMT Val 108/158 Met genotype, with a negative effect of Val allele load. If replicated, the results may be indicative of pharmacogenetic interactions in bipolar disorder.

Clinical factors leading to lamotrigine prescription in bipolar outpatients: subanalysis of the SIN-DEPRES study

BACKGROUND

The use of lamotrigine is a point of discrepancy among the diverse guidelines published on the management of bipolar disorder (BD). Evidence supporting the long-term efficacy is reasonably robust. Nonetheless, the effectiveness of lamotrigine in acute treatment is vigorously debated and it is unclear how this drug is used in routine clinical practice. This subanalysis of the SIN-DEPRES study was designed to understand the clinical profile of bipolar patients receiving lamotrigine.

METHODS

In this prospective national multicenter study, 652 patients with clinically stable bipolar I and II disorder were recruited. Clinical assessments included sociodemographic and clinical data, the Modified Clinical Global Impression scale for BD (CGI-BP-M), the Hamilton Depression Rating Scale (HDRS), and prescriptions of psychotropic medications and their doses.

RESULTS

By means of a logistic regression model, an association between receiving treatment with lamotrigine and the following clinical variables was found: number of past depressive episodes (O.R.=2.875, 95% CI: 1.203-6.869, p=0.018), depressive polarity of the most recent episode (O.R.=1.945, 95% CI: 1.267-2.985, p=0.002), severity in CGI-BD-M depression (O.R.=1.850, 95% CI: 1.215-2.817, p=0.004), bipolar II disorder diagnosis (O.R.=1.635, 95% CI: 1.078-2.482, p=0.021) and number of episodes per year (O.R.=1.310, 95% CI: 1.069-1.605, p=0.009).

LIMITATIONS

Subanalysis of the SIN-DEPRES study with a cross-sectional design.

CONCLUSIONS

The use of lamotrigine in clinical practice is in accordance with most of the guidelines, which support its use in patients with depressive predominant polarity and bipolar II disorder.

Deficit status in bipolar disorder: investigation on prevalence rate and description of seven cases

OBJECTIVE

While the Kraepelinian dichotomy explicitly distinguishes between schizophrenia and bipolar disorder, it remains unclear as to whether a deficit form of bipolar disorder exists.

METHOD

We conducted a study to investigate the prevalence rate of the deficit form of bipolar disorder; the criteria of which were basically adopted by the original proposal for schizophrenia that described the predominance of negative symptoms for over a year. Moreover, we presented a series of cases with "deficit" bipolar disorder to characterize its clinical pictures in detail.

RESULTS

Consecutive outpatients who visited one psychiatric hospital in Tokyo, Japan in March 2007 were evaluated cross-sectionally. Additionally, medical charts of inpatients who were hospitalized in the same hospital between April 2006 and March 2007 were also thoroughly reviewed. Of 494 patients, 7 patients (1.4%; 10.9% of 64 bipolar cases) fulfilled the criteria for bipolar disorder with deficit syndrome. Seven "deficit" cases had a mean±SD age of 61±5 year-old with the age at onset being 25±8 year-old. In addition to pervasive negative symptoms, they exhibited evidence of cognitive impairments close to the magnitude of what is usually noted in schizophrenia (i.e. a mean±SD total IQ score of 80±9 in the Wechsler Adult Intelligence Scale and 0.4±0.5 in the Wisconsin Card Sorting Test, categories achieved).

CONCLUSION

Although preliminary, the evidence on deficit status in patients with bipolar disorder that we found in this study appears more consistent with recent evidence and challenges the Kraepelinian dichotomy that reserves deficit status solely to schizophrenia patients.

Is there a difference in subjective experience of cognitive function in patients with unipolar disorder versus bipolar disorder?

BACKGROUND

Cognitive dysfunction in unipolar disorder (UD) and bipolar disorder (BD) may persist into remission and affect psychosocial function. Executive and memory deficits during remission may be more pronounced in BD than UD. However, patients' subjective experience of cognitive difficulties is poorly understood, and it is unclear whether BD and UD patients experience different cognitive difficulties.

AIMS

To investigate whether there are differences in the quality and magnitude of subjective cognitive difficulties between UD and BD, and which factors influence the subjective cognitive difficulties in these patients.

METHODS

Patients with BD (n = 54) or UD (n = 45) were referred to the outpatient mood disorder clinic at Department of Psychiatry, Copenhagen University Hospital, following hospital discharge. Affective symptoms and patients' experience of cognitive symptoms were assessed at their initial consultation at the clinic.

RESULTS

Patients experienced mild to moderate cognitive impairment despite being in partial or full remission, but there were no differences in subjective difficulties between BD and UD. Subjective cognitive dysfunction was predicted by depression severity, anxiety and mania symptoms rather than by diagnosis, age, gender or alcohol misuse.

CONCLUSION

The absence of difference in subjective cognitive difficulties between UD and BD contrasts with evidence of greater objective dysfunction in BD. This highlights a potential discord between subjective and objective measures of cognitive function. Subjective cognitive function was predicted by affective symptoms, perhaps suggesting that this reflects mood symptoms rather than objective deficits. This points to a clinical need for objective assessment of cognitive function in these patient groups.

Pharmacological approaches in bipolar disorders and the impact on cognition: a critical overview

OBJECTIVE

Historically, pharmacological treatments for bipolar disorders (BD) have been associated with neurocognitive side-effects. We reviewed studies which assessed the impact of several psychopharmacological drugs on the neurocognitive function of BD patients.

METHOD

The PubMed database was searched for studies published between January 1980 and February 2011, using the following terms: bipolar, bipolar disorder, mania, manic episode, or bipolar depression, cross-referenced with cognitive, neurocognitive, or neuropsychological, cross-referenced with treatment.

RESULTS

Despite methodological flaws in the older studies and insufficient research concerning the newer agents, some consistent findings emerged from the review; lithium appears to have definite, yet subtle, negative effects on psychomotor speed and verbal memory. Among the newer anticonvulsants, lamotrigine appears to have a better cognitive profile than carbamazepine, valproate, topiramate, and zonisamide. More long-term studies are needed to better understand the impact of atypical antipsychotics on BD patients' neurocognitive functioning, both in monotherapy and in association with other drugs. Other agents, like antidepressants and cognitive enhancers, have not been adequately studied in BD so far.

CONCLUSION

Pharmacotherapies for BD should be chosen to minimize neurocognitive side-effects, which may already be compromised by the disease process itself. Neurocognitive evaluation should be considered in BD patients to better evaluate treatment impact on neurocognition. A comprehensive neuropsychological evaluation also addressing potential variables and key aspects such as more severe cognitive deficits, comorbidities, differential diagnosis, and evaluation of multiple cognitive domains in longitudinal follow-up studies are warranted.

Neurocognitive impairment and psychosocial functioning in bipolar II disorder

OBJECTIVE

There is a growing body of evidence on neurocognitive impairment in euthymic bipolar patients, but this issue has been studied mostly in bipolar I disorder, data on bipolar II (BD-II) are scant and discrepant. The two aims of this study were to ascertain whether strictly defined euthymic BD-II patients would present neurocognitive disturbances and to evaluate their impact on functional outcome.

METHOD

Forty-three BD-II patients and 42 demographically and educationally matched healthy subjects were assessed with a comprehensive neuropsychological test battery and with the Social and Occupational Functioning Assessment Scale (SOFAS). The euthymia criteria were reduced (Hamilton Rating Scale for Depression score ≤6 and a Young Mania Rating Scale score ≤6) to minimize the influence of subdepressive symptomatology on cognition and functioning.

RESULTS

BD-II patients showed a significantly lower performance on several measures of attention, learning and verbal memory, and executive function compared with healthy controls. The presence of subthreshold depressive symptomatology and one measure related to executive function (Trail Making Test, part B) was the variables that best predicted psychosocial functioning measured with the SOFAS.

CONCLUSION

This report provides further evidence that euthymic BD-II patients present cognitive impairment which may impact psychosocial functioning.

Subthreshold symptoms in bipolar disorder: impact on neurocognition, quality of life and disability

OBJECTIVE

To provide empirical evidence of the effect of subthreshold symptomatology (both depressive and manic) on psychosocial functioning, neurocognition and quality of life in bipolar disorder.

METHODS

A total of 133 participants were enrolled for this study (bipolar patients, n=103; healthy controls, n=30). Patients were divided into two groups according to their levels of subthreshold symptomatology: the subsyndromic group was constituted by those patients with upper levels of subthreshold symptomatology (HDRS≥4 and YMRS≥3) and the asymptomatic group represented the patients with lower scores (HDRS≤3 and YMRS≤2). All participants were administered a comprehensive neuropsychological battery. Moreover the patients answered the SF-36 (Quality of Life, QoL) and were interviewed with the WHODAS-2 (Psychosocial functioning and disability). One-way ANOVA were used in order to compare the differences between the three groups.

RESULTS

The analyses revealed that both patients groups, albeit free of acute symptoms of mania or depression, differed in terms of functioning and disability assessed with the WHODAS-2. Specifically, the total global score of disability was higher for the subsyndromic group indicating more impairment (p=0.008). The same pattern of impairment was found for three of its domains: "understanding and communicating" (p=0.013); "self-care" (p=0.035) and "getting along with others" (p=0.024). The subsyndromic group also scored lower when compared to their counterparts in the Mental Component of QoL of the SF-36 (p=0.045). Finally, in the neuropsychological performance verbal learning and memory was found to be impaired regardless the levels of subthreshold symptomatology, suggesting that this variable is a robust indicator of neuropsychological impairment in BD patients.

CONCLUSIONS

This report presents empirical data suggesting a moderate impact of subthreshold symptoms on functioning/disability and QoL and a discrete impact on neuropsychological impairment.

Bipolar disorder: clinical perspectives and implications with cognitive dysfunction and dementia

Introduction. Cognitive dysfunction as a core feature in the course of bipolar affective disorder (BPD) is a current subject of debate and represents an important source of psychosocial and functional burden. Objectives. To stand out the connection and clinical implications between cognitive dysfunction, dementia, and BPD. Methods. A nonsystematic review of all English language PubMed articles published between 1995 and 2011 using the terms "bipolar disorder," "cognitive dysfunction," and "dementia". Discussion. As a manifestation of an affective trait or stage, both in the acute phases and in remission, the domains affected include attention, executive function, and verbal memory. The likely evolution or overlap with the behavioural symptoms of an organic dementia allows it to be considered as a dementia specific to BPD. This is named by some authors, as BPD type VI, but others consider it a form of frontotemporal dementia. It is still not known if this process is neurodevelopmental or neurodegenerative in nature, or both simultaneously. The assessment should consider the iatrogenic effects of medication, the affective symptoms, and a neurocognitive evaluation. Conclusion. More specific neuropsychological tests and functional imaging studies are needed and will assume an important role in the near future for diagnosis and treatment.

Relationship of neurocognitive deficits to diagnosis and symptoms across affective and non-affective psychoses

INTRODUCTION

Neurocognitive dysfunction is believed to be a core feature of schizophrenia and is increasingly recognized as a common symptom dimension in bipolar disorder. Despite a copious literature on neurocognition in these disorders, the relationship amongst neurocognition, symptoms, and diagnosis remains unclear. We examined neurocognitive functioning in a cross-diagnostic sample of patients with psychotic disorders. Based on previous findings, it was hypothesized that neurocognitive functioning would be impaired in all three patient groups, and that groups would be similarly impaired on all neuropsychological measures. Additionally, we predicted that negative symptoms but not positive, general, or mood symptoms, would be associated with neurocognitive functioning.

METHOD

Neurocognitive functioning and symptoms were assessed in participants with schizophrenia (n=25), schizoaffective disorder (n=29), or bipolar disorder with psychosis (n=31), and in healthy controls (n=20).

RESULTS

Neurocognitive functioning was significantly impaired in all patient groups, and groups did not differ by diagnosis on most measures. A series of linear regressions revealed that negative symptoms (but no other clinical symptom) predicted poorer executive functioning across groups. Diagnosis was not a significant predictor of any neurocognitive variable.

DISCUSSION

Neurocognitive deficits were pronounced in this cross-diagnostic sample of patients with psychotic disorders, and did not differ by diagnosis. Neurocognitive dysfunction may represent a symptom dimension that spans diagnostic categories, and may reflect shared pathogenic processes. As neurocognitive dysfunction is among the strongest predictors of outcome in patients, efforts to treat these deficits, which have shown promise in schizophrenia, should be extended to all patients with psychosis.

Neurocognitive impairment across the bipolar spectrum

Bipolar disorder is a severe mental illness that affects nearly 4.4% of the general population when bipolar spectrum disorders are taken into account. Neurocognitive impairment is thought to be a core deficit of this illness since it is present during euthymia. In fact, 40-60% of euthymic patients present with neurocognitive disturbances. Not only the clinical factors but also disturbances in neurocognition can influence the functional outcome of BD patients. Hence, further research is needed in order to clarify the relationship between these variables. Despite the growing body of evidence that has emerged during the last decade, no unique neurocognitive profile has been proposed yet for either BD subtype. The majority of the studies recluted heterogeneous samples (including both bipolar I and II) or focused on BD-I patients only. The aim of this review is to give an overall picture of the main neurocognitive disturbances found in the bipolar spectrum and particularly in BD-II, where the findings are more ambiguous. An extensive review of all the literature has been done regarding this subtype (from 1980 until July 2009). Data available until now suggest that deficits are present across the bipolar spectrum (BD-I and BD-II), but they seem slightly more severe in BD-I. The extent to which either subtype share-or not-some similarities is still unknown. More studies are required but it would also be interesting to reach a consensus in the neuropsychological assessment of BD to facilitate comparisons between the different studies.

Functional outcome in bipolar disorder: the big picture

Previous research on functional outcome in bipolar disorder (BD) has uncovered various factors that exacerbate psychosocial disability over the course of illness, including genetics, illness severity, stress, anxiety, and cognitive impairment. This paper presents an integrated view of these findings that accounts for the precipitous decline in psychosocial functioning after illness onset. The proposed model highlights a number of reciprocal pathways among previously studied factors that trap people in a powerful cycle of ailing forces. The paper discusses implications to patient care as well as the larger social changes required for shifting the functional trajectory of people with BD from psychosocial decline to growth.

Are bipolar II patients cognitively impaired? A systematic review

BACKGROUND

There is evidence that bipolar disorder (BD) is associated with significant neurocognitive deficits and this occurs in individuals with BD type I (BD I) and with BD type II (BD II). Only a few studies have focused on cognitive impairment in BD II. The aim of this study was to describe the pattern of cognitive impairment in patients with BD II, in order to identify specific cognitive deficits that distinguish BD II from BD I patients as well as from healthy subjects.

METHOD

We performed a systematic review of the literature of neuropsychological studies of BD II published between 1980 and July 2009. Fourteen articles fulfilled the inclusion criteria and were included in this review.

RESULTS

Main cognitive deficits found in BD II include working memory and some measures of executive functions (inhibitory control) and approximately half of the studies also detected verbal memory impairment.

CONCLUSIONS

There are subtle differences between the two subtypes regarding cognition. This may suggest neurobiological differences between the two subgroups which will be helpful in order to determine cognitive endophenotypes in BD subtypes.

Neurocognitive performance in children and adolescents with bipolar disorder: a review

A number of studies have reported the evidence of cognitive deficits in adult bipolar patients. Recently, there has been a shift in research on neurocognitive performance in bipolar disorder (BD) towards examining younger age groups. A review of the literature on neurocognitive impairments in BD in childhood and adolescence was conducted. We searched systematically for studies in samples of age groups younger than 18 years of age in average that included either a healthy control group or normative data for the cognitive tests used. Twenty-one original articles were found and reviewed. Children and adolescents with BD show deficits in a variety of cognitive areas. The most consistent results were found for impairments in verbal memory. A majority of studies also indicated impairments in working memory. Similar pattern of neurocognitive impairment was found in children and adolescents as compared to adults suffering from BD. The neurocognitive deficits need to be recognized and incorporated into individual treatment programs.

Insight in bipolar disorder: associations with cognitive and emotional processing and illness characteristics

OBJECTIVE

To investigate the multifactorial relationship between illness insight, cognitive and emotional processes, and illness characteristics in bipolar disorder patients.

METHODS

Data from 85 euthymic or mildly to moderately depressed bipolar disorder patients were evaluated. Insight was measured using the Mood Disorder Insight Scale (total score and subscale scores: awareness of illness, symptom attribution, and need for treatment). Cognitive and emotional functioning was measured in four domains (processing speed, memory, executive functioning, and emotional learning) in addition to premorbid IQ. Illness characteristics were assessed using the Mini-International Neuropsychiatric Interview, the Questionnaire for Bipolar Disorder, and the Inventory of Depressive Symptomatology-self rating scale. Regression analyses were performed for the whole sample. Post-hoc, interactions with lifetime psychotic features (LPF) were statistically tested and if significant, analyses were repeated for patients with (n = 36) and without (n = 49) LPF separately.

RESULTS

In the whole group, better insight was associated with lower processing speed, better memory performance, increased emotional learning, higher level of depressive symptoms, and longer duration of illness. Patients with LPF had worse awareness of illness, but better symptom attribution than patients without LPF. No group differences for need for treatment and overall insight were found. Finally, processing speed significantly predicted subscores for symptom attribution in patients with LPF only.

CONCLUSIONS

Cognitive functioning as well as impairments in emotional learning and psychotic features independently contributes to impaired insight in bipolar disorder. Processing speed seems to be a key variable in the prediction of insight in patients with LPF and not in patients without LPF.

A functional MRI study of working memory in adolescents and young adults at genetic risk for bipolar disorder: preliminary findings

OBJECTIVES

In this report, we seek to (i) identify a potential neuroimaging endophenotype for bipolar disorder (BD) in emotion regulatory and autonomic circuitry in young first-degree relatives of persons with BD; and (ii) replicate our previous work identifying the functional neuroanatomy of working memory (WM) in an older sample of relatives of persons with BD.

METHODS

Ten adolescent and young adult (age 13-24) unmedicated, non-ill, first-degree relatives of persons with BD (RELS) and 10 demographically comparable healthy controls performed a 2-back WM task and a 0-back control task during functional magnetic resonance imaging (fMRI). fMRI data were collected on a 1.5 Tesla scanner and analyzed using SPM-2. Mood was assessed on the day of scanning.

RESULTS

The groups did not differ on any demographic, neuropsychological, or in-scanner task performance variables. In contrast to controls, RELS showed (i) weak task-dependent modulation activity in the cerebellar vermis (CV), insula, and amygdala/parahippocampal region, and (ii) exaggerated modulation of activity in the frontopolar cortex and brainstem, even after controlling for potential confounders. Many of the group differences were driven by differences in activity in the low-level (0-back) baseline task.

CONCLUSIONS

Young, unmedicated RELS exhibited altered task-dependent modulation of frontopolar, CV, and insula activity during WM, especially during the low-level (0-back) baseline task. Results are largely consistent with our initial study of older adult RELS, suggesting these alterations may represent biomarkers of genetic risk for BD.

Cognitive abilities and clinical variables in bipolar I depressed and euthymic patients and controls

BACKGROUND

While studies demonstrated that bipolar patients (BP) display cognitive deficits during mood episodes and remission, little is known about the clinical influences underlying these deficits. The aim of this study was to compare the performance of euthymic and depressed BPs and non-affective/psychotic disorder controls at several cognitive tasks, exploring which clinical variables influenced the performance of these subtests. It is hypothesized that the cognitive deficits in rank order are: depressed BPs > euthymic BPs > controls.

METHODS

Sixty-five bipolar-I outpatients and thirty-four controls were assessed by the Brazilian version of the Wechsler Adult Intelligence Scale, Third Edition (WAIS-III). BPs were divided into depressed and euthymics, and these two groups were then compared to non-affective/psychotic disorder controls.

RESULTS

For 12 of 14 subtest scores, comparisons yielded statistically significant (p < 0.05) between-group differences, including three subtests of attention and working memory (Digit Span and its two subtests) with both depressed and euthymic BPs, compared to controls, displaying significantly worse performance, and six subtests of visual and working memory with depressed (but not euthymic) BPs performing worse than controls. For all subtests, comparisons of depressed and euthymic patients' scores were non-significant. Performance on several subtests was negatively predicted by the severity of the disorder in both patient groups.

LIMITATIONS

The cross-sectional design of the study, as well as confounding effects of medications and co-morbidities.

CONCLUSIONS

The fact that the impairment of cognitive performance of both groups of patients is influenced by the severity of the illness is consistent with the literature.

Executive functioning in familial bipolar I disorder patients and their unaffected relatives

OBJECTIVE

To compare the executive function of patients with familial bipolar I disorder (BP-I) with a history of psychotic symptoms to their first-degree relatives and normal controls.

METHODS

Three domains of executive function: response inhibition, working memory, and cognitive set shifting were assessed in 44 familial patients with a lifetime diagnosis of BP-I who had experienced psychotic symptoms, 42 of their unaffected first-degree relatives, and 47 controls.

RESULTS

Bipolar disorder patients and their unaffected relatives had significantly worse scores for response inhibition compared to healthy controls. The groups did not differ in working memory or cognitive set shifting.

CONCLUSIONS

Impairments in response inhibition are associated with both psychotic bipolar disorder and genetic liability for this illness. Our results indicate that deficits in this specific domain of executive functioning are a promising candidate endophenotype for psychotic bipolar disorder.

Bipolar disorder and dementia: where is the link?

Cognitive disorders appearing in the course of bipolar disease have been identified, and recent studies have defined the neuropsychological characteristics of this pathology, which includes attention, executive function, memory and language disorders. However, questions remain concerning the appearance of dementia symptoms over the course of bipolar disorder in certain patients: is it a chance association or is there a connection between bipolar disorders and dementia? If the latter hypothesis is considered, what is the nature of the dementia, which might be considered as a dementia specific to bipolar disorder? Current clinical, neuropsychological and cerebral imaging data are inconclusive, but similarities with frontotemporal dementia might be highlighted. Functional imaging studies might provide answers as well as more specific tests in neuropsychology. The cause of cognitive damage in bipolar disease also raises questions concerning a neurodevelopmental or neurodegenerative process, because several factors seem to influence cognition and these two processes might occur simultaneously. Long-term studies are necessary to determine whether cognitive deterioration in bipolar disease is stable or progressive. There might also be different neurobiological subgroups of patients with bipolar disease.

Aerobic physical exercise as a possible treatment for neurocognitive dysfunction in bipolar disorder

BACKGROUND

Neurocognitive dysfunction associated with bipolar disorder (BD) is pervasive, persistent across illness phases, and is demonstrated to predispose and portend psychosocial impairment. Moreover, no approved therapies for various phases of BD have been shown to reliably improve any dimension of neurocognitive performance. In this article, we emphasize that aerobic physical exercise is a viable neurocognitive-enhancing adjunctive treatment for patients with BD. The overarching aim of this review is to emphasize that aerobic physical exercise is a viable neurocognitive-enhancing adjunctive treatment for patients with BD.

METHODS

We conducted PubMed and Google Scholar searches of all English-language articles published between January 1966 and February 2010 using the search terms bipolar disorder, major depressive disorder, depression, exercise, and physical activity cross-referenced with each other and the following terms: cognition, executive function, learning, memory, attention, emotion, and behavior. Articles selected for review were based on adequacy of sample size, use of standardized experimental procedures, validated assessment measures, and overall quality.

RESULTS

Available studies have documented an array of persisting neurocognitive deficits across disparate bipolar populations. Abnormalities in verbal working memory are highly replicated; deficits in executive function, learning, attention, and processing speed are also a consistent abnormality. The effect sizes of neurocognitive deficits in BD are intermediate between those reported in schizophrenia and major depressive disorder. Several original reports and reviews have documented the neurocognitive-enhancing effects of aerobic exercise in the general population as well as across diverse medical populations and ages. Proposed mechanisms involve nonexclusive effects on neurogenesis, neurotrophism, immunoinflammatory systems, insulin sensitivity, and neurotransmitter systems. Each of these effector systems are implicated in both normal and abnormal neurocognitive processes in BD.

CONCLUSION

Available evidence provides a rationale for empirically evaluating the neurocognitive benefits of aerobic exercise in BD.

Deficits in visual sustained attention differentiate genetic liability and disease expression for schizophrenia from Bipolar Disorder

BACKGROUND

There is mounting evidence for shared genetic liability to psychoses, particularly with respect to Schizophrenia (SZ) and Bipolar Disorder (BD), which may also involve aspects of cognitive dysfunction. Impaired sustained attention is considered a cardinal feature of psychoses but its association with genetic liability and disease expression in BD remains to be clarified.

METHODS

Visual sustained attention was assessed using the Degraded Symbol Continuous Performance Test (DS-CPT) in a sample of 397 individuals consisting of 50 remitted SZ patients, 119 of their first degree relatives, 47 euthymic BD patients, 88 of their first degree relatives and 93 healthy controls. Relatives with a personal history of schizophrenia or bipolar spectrum disorders were excluded. Performance on the DS-CPT was evaluated based on the response criterion (the amount of perceptual evidence required to designate a stimulus as a target) and sensitivity (a signal-detection theory measure of signal/noise discrimination).

RESULTS

We found no effect of genetic risk or diagnosis for either disorder on response criterion. In contrast, impaired sensitivity was seen in SZ patients and to a lesser degree in their relatives but not in BD patients and their relatives. These findings were not attributable to IQ, medication, age of onset or duration of illness.

CONCLUSIONS

Our results argue for the specificity of visual sustained attention impairment in differentiating SZ from BD. They also suggest that compromised visual information processing is a significant contributor to these deficits in SZ.

New ways to classify bipolar disorders: going from categorical groups to symptom clusters or dimensions

Current psychiatric disorder classifications are based exclusively on categorical models, which were designed to increase the reliability of diagnoses. However, this system has some limitations, and various psychiatric disorders may be classified using a dimensional approach, which is more appropriate when no clear boundaries exist between entities or when examining various features on a continuum. Thus, the forthcoming DSM-5 appears to be undertaking a hybrid approach by including categorical models associated with dimensions. We aim to review examples of dimensions or symptom clusters associated with a categorical approach that could be useful in refining bipolar disorder classification. We selected predominant polarity, psychotic symptoms, inhibition/activation behavioral level, and emotional reactivity to define mood episodes, impulsivity/suicidality/substance misuse, and cognitive impairment. The selection was based on the fact that these dimensions or symptom clusters are currently being discussed to be implemented in the DSM-5 and/or may orientate toward the choice of specific treatments and represent more homogeneous and thus more appropriate subgroups for research purposes. In the future, there will be a need to identify biomarkers that can definitively validate the use of these criteria.

Cognitive functioning in patients with bipolar disorder: association with depressive symptoms and alcohol use

BACKGROUND

Cognitive dysfunction is clearly recognized in bipolar patients, but the degree of impairment varies due to methodological factors as well as heterogeneity in patient populations. The goal of this study was to evaluate cognitive functioning in bipolar patients and to assess its association with depressive symptoms. Post hoc the relationship with lifetime alcohol use disorder was explored.

METHODOLOGY/PRINCIPAL FINDINGS

The study included 110 bipolar patients and 75 healthy controls. Patients with severe depressive symptoms, (hypo)manic symptoms and current severe alcohol use disorder were excluded. Diagnoses were evaluated via the Mini-International Neuropsychiatric Interview. Cognitive functioning was measured in domains of psychomotor speed, speed of information processing, attentional switching, verbal memory, visual memory, executive functioning and an overall mean score. Severity of depression was assessed by the Inventory of Depressive Symptomatology-self rating. Patients were euthymic (n = 46) or with current mild (n = 38) or moderate (n = 26) depressive symptoms. Cognitive impairment was found in 26% (z-score 2 or more above reference control group for at least one domain) of patients, most prominent in executive functioning (effect size; ES 0.49) and speed of information processing (ES 0.47). Depressive symptoms were associated with dysfunction in psychomotor speed (adjusted beta 0.43; R(2) 7%), speed of information processing (adjusted beta 0.36; R(2) 20%), attentional switching (adjusted beta 0.24; R(2) 16%) and the mean score (adjusted beta 0.23; R(2) 24%), but not with verbal and visual memory and executive functioning. Depressive symptoms explained 24% of the variance in the mean z-score of all 6 cognitive domains. Comorbid lifetime alcohol use (n = 21) was not associated with cognitive dysfunction.

CONCLUSIONS/SIGNIFICANCE

Cognitive dysfunction in bipolar disorder is more severe in patients with depressive symptoms, especially regarding speed and attention. Therefore, interpretation of cognitive functioning in patients with depressive symptoms should be cautious. No association was found between cognitive functioning and lifetime comorbid alcohol use disorder.