Neuropsychological task performance in bipolar spectrum illness: genetics, alcohol abuse, medication and childhood trauma

Differential relations between fronto-limbic metabolism and executive function in patients with remitted bipolar I and bipolar II disorder

OBJECTIVES

The aim of this study was to investigate the relationship between resting brain glucose metabolism and cognitive profiles in patients with remitted bipolar I disorder (BD-I) and bipolar II disorder (BD-II). We hypothesized that BD-I patients (compared to BD-II patients) would perform worse on tests of cognitive function because of abnormal metabolism in the prefrontal cortex and other mood-related brain areas.

METHODS

Thirty-four patients with remitted bipolar disorder (BD) (BD-I = 17, BD-II = 17) under treatment and 17 well-matched healthy controls received both fluorodeoxyglucose ((18) F-FDG) positron emission tomography (PET) and neuropsychological tests of attention, memory, and executive function.

RESULTS

Clinical features in patients with BD-I and BD-II were comparable. Executive function, as indicated by performance on the Wisconsin Card Sorting Test, was significantly worse (i.e., higher percentage of errors, lower percentage of conceptual level responses, and fewer categories completed) in BD-I patients than in BD-II patients and healthy subjects. No difference in attention and memory tests was found among these three groups. Brain PET analysis showed that BD-I patients (compared to BD-II patients) had significantly lower glucose uptake in the bilateral anterior cingulum, insula, striatum, and part of the prefrontal cortex, and higher glucose uptake in the left parahippocampus. Further analyses revealed significant correlations between poor executive function and abnormal glucose uptake in other brain areas in BD-I patients.

CONCLUSIONS

There are neurobiological differences between subtypes of BD. BD-I is associated with more impaired fronto-limbic circuitry, which might account for reduced executive function in BD-I patients during remission.

A randomized, double-blind, controlled trial evaluating the effect of intranasal insulin on neurocognitive function in euthymic patients with bipolar disorder

BACKGROUND

Neurocognitive deficits are prevalent, persistent, and implicated as mediators of functional impairment in adults with bipolar disorder. Notwithstanding progress in the development of pharmacological treatments for various phases of bipolar disorder, no available treatment has been proven to be reliably efficacious in treating neurocognitive deficits. Emerging evidence indicates that insulin dysregulation may be pertinent to neurocognitive function. In keeping with this view, we tested the hypothesis that intranasal insulin administration would improve measures of neurocognitive performance in euthymic adults with bipolar disorder.

METHODS

Sixty-two adults with bipolar I/II disorder (based on the Mini International Neuropsychiatric Interview 5.0) were randomized to adjunctive intranasal insulin 40 IU q.i.d. (n = 34) or placebo (n = 28) for eight weeks. All subjects were prospectively verified to be euthymic on the basis of a total score of ≤ 3 on the seven-item Hamilton Depression Rating Scale (HAMD-7) and ≤ 7 on the 11-item Young Mania Rating Scale (YMRS) for a minimum of 28 consecutive days. Neurocognitive function and outcome was assessed with a neurocognitive battery.

RESULTS

There were no significant between-group differences in mean age of the subjects {i.e., mean age 40 [standard deviation (SD) = 10.15] years in the insulin and 39 [SD = 10.41] in the placebo groups, respectively}. In the insulin group, n = 27 (79.4%) had bipolar I disorder, while n = 7 (21.6%) had bipolar II disorder. In the placebo group, n = 25 (89.3%) had bipolar I disorder, while n = 3 (10.7%) had bipolar II disorder. All subjects received concomitant medications; medications remained stable during study enrollment. A significant improvement versus placebo was noted with intranasal insulin therapy on executive function (i.e., Trail Making Test-Part B). Time effects were significant for most California Verbal Learning Test indices and the Process Dissociation Task-Habit Estimate, suggesting an improved performance from baseline to endpoint with no between-group differences. Intranasal insulin was well tolerated; no subject exhibited hypoglycemia or other safety concerns.

CONCLUSIONS

Adjunctive intranasal insulin administration significantly improved a single measure of executive function in bipolar disorder. We were unable to detect between-group differences on other neurocognitive measures, with improvement noted in both groups. Subject phenotyping on the basis of pre-existing neurocognitive deficits and/or genotype [e.g., apolipoprotein E (ApoE)] may possibly identify a more responsive subgroup.

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.

Childhood maltreatment and clinical outcomes of bipolar disorder

OBJECTIVE

Adverse life events, especially early trauma, play a major role in the course and expression of bipolar disorder (BD). The aim of this article is to present a systematic review about the impact of childhood trauma on the clinical course of BD.

METHOD

A computer-aided search was performed in Medline, ISI database, EMBASE, PsychInfo, Centre for Reviews and Dissemination, and Databases of Thomson Reuters at April 2011, supplemented by works identified from the reference lists of the first selected papers. Two investigators systematically and independently examined all articles, selecting those according inclusion and exclusion criteria.

RESULTS

Four hundred fifteen articles were identified, of which 19 remained in the review after exclusion criteria were applied. In general, childhood maltreatment predicted worsening clinical course of BD. After assessing the quality of the data and of the measurements, childhood maltreatment can be strongly associated to early onset of disorder, suicidality, and substance abuse disorder in patients with BD.

CONCLUSION

Data suggest that childhood abuse and neglect are risk factors associated with worsening clinical course of BD. The conclusions should be interpreted with caution because all the studies included are cross-sectional and the majority are showing inconsistencies regarding childhood trauma as independent variable and how it is assessed.

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.

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.

Meta-analytic review of neurocognition in bipolar II disorder

OBJECTIVE

The clinical distinction between bipolar II disorder (BD II) and bipolar I disorder (BD I) is not clear-cut. Cognitive functioning offers the potential to explore objective markers to help delineate this boundary. To examine this issue, we conducted a quantitative review of the cognitive profile of clinically stable patients with BD II in comparison with both patients with BD I and healthy controls.

METHOD

Meta-analytical methods were used to compare cognitive functioning of BD II disorder with both BD I disorder and healthy controls.

RESULTS

Individuals with BD II were less impaired than those with BD I on verbal memory. There were also small but significant difference in visual memory and semantic fluency. There were no significant differences in global cognition or in other cognitive domains. Patients with BD II performed poorer than controls in all cognitive domains.

CONCLUSION

Our findings suggest that with the exception of memory and semantic fluency, cognitive impairment in BD II is as severe as in BD I. Further studies are needed to investigate whether more severe deficits in BD I are related to neurotoxic effects of severe manic episodes on medial temporal structures or neurobiological differences from the onset of the illness.

A 2-year naturalistic study on cognitive functioning in bipolar disorder

OBJECTIVE

Cognitive alterations in bipolar disorder may reflect genetic influence. However, to what degree mood, medication, thyroid function and other factors impact on longitudinal cognitive functioning remains unclear.

METHOD

A group of patients with bipolar (spectrum) disorder (n = 76) underwent two monthly cognitive assessments over a 2-year period in a prospective, repeated measures design. Regression models were used to investigate associations with predictors, corrected for multiple testing.

RESULTS

Patients with bipolar disorder performed worse than healthy controls (n = 61) on all cognitive domains tested. Effect sizes were small, with a maximum of -0.36 for sustained attention. However, cognitive performance varied substantially over the 2-year follow-up, co-varying with subjective cognitive complaints and impacting on functioning. Alterations in sustained attention and motor speed were the only impairments that were invariant over time. Predictors had very limited explanatory power on temporal variation in cognition. Use of second-generation antipsychotics was associated with the largest negative effects on cognition, which were evident in the areas of motor speed and basic information processing (-0.35 < β < -0.5).

CONCLUSION

Cognitive function in bipolar disorder varies significantly over time, largely independent of clinical factors. The temporal stability of sustained attention is the exception, suggesting it may represent a possible candidate intermediary phenotype.

Neuropsychological functions in Han Chinese patients in Taiwan with bipolar II disorder comorbid and not comorbid with alcohol abuse/alcohol dependence disorder

OBJECTIVE

Studies exploring neuropsychological functions of bipolar disorder (BP) specifically include patients comorbid with alcohol abuse (AB), alcohol dependence (AD), or both (AB/AD). Contradictory assessments of neuropsychological impairment may be caused by not excluding the confounding effects of comorbid AB/AD. Most of the literature discusses BP without subtyping, which overlooks that BP-II may be a valid diagnosis different from BP-I. Because neuropsychological functions are involved in overall BP-II outcomes, we hypothesized that the neuropsychological functions of patients with BP-II comorbid with AD (BP(+AD)) are significantly different from and more impaired than those of patients with BP-II not comorbid with AD (BP(-AD)).

METHODS

Using DSM-IV criteria, the study included 69 patients with BP-II (19 with BP(+AD); 28 with BP(-AD)) and 22 healthy controls compared using a battery of neuropsychological tests that assessed memory, psychomotor speed, and certain aspects of frontal executive function. All BP-II patients were in an inter-episode period (a period of remission between states of mania, hypomania, and depression).

RESULTS

BP(+AD) patients had lower scores than did BP(-AD) patients and controls in verbal memory, visual memory, attention, psychomotor speed, and executive function. Working memory was poorer for BP(+AD) than BP(-AD) patients and for both BP groups than for controls.

CONCLUSIONS

BP(+AD) patients manifested wide neuropsychological dysfunctions, and BP(-AD) patients showed a reduction in working memory, which suggested that working memory might be related to a history of BP-II. Neuropsychological dysfunctions seemed more strongly associated with AB/AD than with BP-II in inter-episode periods.

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.

Cognitive impairment in patients with a schizoaffective disorder: a comparison with bipolar patients in euthymia

Objectives

Several studies have shown persistent neurocognitive impairment in patients with a bipolar affective disorder (BD) even in euthymia as well as in patients with a schizoaffective disorder (SAD). The aim of our study was to compare the neuropsychological performance between these two groups. Confounding variables were controlled to enhance our understanding of cognitive dysfunction in both BD and SAD.

Methods

Several domains of neurocognitive function, executive function, memory, attention, concentration and perceptuomotor function were examined in 28 euthymic SAD patients and 32 BD patients by using a neuropsychological test battery. The Hamilton Depression Rating Scale (HAMD), Montgomery-Asberg Depression Rating Scale (MADRS) and Young Mania Rating Scale (YMRS) were used to evaluate the patients' clinical status. Data analysis was performed by using a multivariate analysis of covariance (ANCOVA/MANCOVA).

Results

Euthymic SAD patients showed greater cognitive impairment than euthymic BD patients in the tested domains including declarative memory and attention. Putative significant group differences concerning cognitive flexibility vanished when controlled for demographic and clinical variables. Age and medication were robust predictors to cognitive performance of both SAD and BD patients.

Conclusions

Our results point out the worse cognitive outcome of SAD compared to BD patients in remission. Remarkably, the variance is higher for some of the test results between the groups than within each group, this being discussed in light of the contradictive concept of SAD.

Successful treatment of bipolar disorder II and ADHD with a micronutrient formula: a case study

Bipolar disorder with co-occurring attention-deficit/hyperactivity disorder (ADHD) is a challenge to treat. Ten previous reports have shown potential benefit of a micronutrient treatment (consisting mainly of vitamins and minerals) for various psychiatric symptoms, including mood and ADHD. This case study aimed to investigate the longer term impact of the micronutrients on both psychiatric and neurocognitive functioning in an off-on-off-on (ABAB) design with 1 year follow-up. A 21-year-old female with bipolar II disorder, ADHD, social anxiety, and panic disorder entered an open-label trial using a nutritional treatment following a documented 8 year history of on-going psychiatric symptoms not well managed by medications. After 8 weeks on the formula she showed significant improvements in mood, anxiety, and hyperactivity/impulsivity. Blood test results remained normal after 8 weeks on the formula. She did not report any adverse side effects associated with the treatment. She then chose to come off the formula; after 8 weeks her depression scores returned to baseline, and anxiety and ADHD symptoms worsened. The formula was reintroduced, showing gradual improvement in all psychiatric symptoms. This case represents a naturalistic ABAB design showing on-off control of symptoms. After 1 year, the patient is now in remission from all mental illness. Neurocognitive changes mirrored behavioral changes, showing improved processing speed, consistency in response speed, and verbal memory. A placebo response and expectancy effects cannot be ruled out although previous poor response to treatment and the duration of the current positive response decrease the likelihood that other factors better explain change. These consistently positive outcomes alongside an absence of side effects indicate that further research, particularly larger and more controlled trials, is warranted using this multinutrient approach.

Risk and resilience in bipolar disorder: rationale and design of the Vulnerability to Bipolar Disorders Study (VIBES)

BD (bipolar disorder) is among the ten most significant causes of disability worldwide. Neuroscientists and clinicians have yet to meet the challenge of reducing this disability burden. The main obstacle to date has been our incomplete understanding of the pathophysiology of BD which thwarts primary prevention and early diagnosis and hinders effective treatment. There is a need to move beyond diagnostic approaches based purely on behavioural observation, as they lack reliability and biological validity. The present article reviews the evidence for cognitive, brain structural and functional correlates of genetic predisposition to BD and highlights biological markers of risk as well as factors that might protect against disease expression. It also outlines the rational and design of the Vulnerability to Bipolar Disorders Study (VIBES), which exemplifies a promising approach to delineating biological mechanisms mediating risk, resilience and disease expression in BD.

Amygdala volume in depressed patients with bipolar disorder assessed using high resolution 3T MRI: the impact of medication

MRI-based reports of both abnormally increased and decreased amygdala volume in bipolar disorder (BD) have surfaced in the literature. Two major methodological weaknesses characterizing extant studies are treatment with medication and inaccurate segmentation of the amygdala due to limitations in spatial and tissue contrast resolution. Here, we acquired high-resolution images (voxel size=0.55 x 0.55 x 0.60 mm) using a GE 3T MRI scanner, and a pulse sequence optimized for tissue contrast resolution. The amygdala was manually segmented by one rater blind to diagnosis, using coronal images. Eighteen unmedicated (mean medication-free period 11+/-10 months) BD subjects were age and gender matched with 18 healthy controls, and 17 medicated (lithium or divalproex) subjects were matched to 17 different controls. The unmedicated BD patients displayed smaller left and right amygdala volumes than their matched control group (p<0.01). Conversely, the BD subjects undergoing medication treatment showed a trend towards greater amygdala volumes than their matched HC sample (p=0.051). Right and left amygdala volumes were larger (p<0.05) or trended larger, respectively, in the medicated BD sample compared with the unmedicated BD sample. The two control groups did not differ from each other in either left or right amygdala volume. BD patients treated with lithium have displayed increased gray matter volume of the cortex and hippocampus relative to untreated BD subjects in previous studies. Here we extend these results to the amygdala. We raise the possibility that neuroplastic changes in the amygdala associated with BD are moderated by some mood stabilizing medications.

Evidence-based guidelines for treating bipolar disorder: revised second edition--recommendations from the British Association for Psychopharmacology

The British Association for Psychopharmacology guidelines specify the scope and target of treatment for bipolar disorder. The second version, like the first, is based explicitly on the available evidence and presented, like previous Clinical Practice guidelines, as recommendations to aid clinical decision making for practitioners: they may also serve as a source of information for patients and carers. The recommendations are presented together with a more detailed but selective qualitative review of the available evidence. A consensus meeting, involving experts in bipolar disorder and its treatment, reviewed key areas and considered the strength of evidence and clinical implications. The guidelines were drawn up after extensive feedback from participants and interested parties. The strength of supporting evidence was rated. The guidelines cover the diagnosis of bipolar disorder, clinical management, and strategies for the use of medicines in treatment of episodes, relapse prevention and stopping treatment.

Hot and cold cognition in unmedicated depressed subjects with bipolar disorder

OBJECTIVES

Neuropsychological studies in subjects with bipolar disorder (BD) have reported deficits on a variety of cognitive measures. However, because the majority of subjects were medicated at the time of testing in previous studies, it is currently unclear whether the pattern of deficits reported is related to BD itself or to psychotropic medication. We addressed this issue by examining cognitive performance in a group of unmedicated, currently depressed subjects with BD.

METHODS

Forty-nine unmedicated subjects who met DSM-IV criteria for BD, depressed phase, and 55 control subjects participated in this study. Most patients were diagnosed with bipolar II disorder. Performance on emotion-dependent, or 'hot', and emotion-independent, or 'cold', cognitive tasks was assessed using tests from the Cambridge Neuropsychological Test Automated Battery.

RESULTS

The groups were well matched with respect to general intelligence and demographic variables. Deficits in the unmedicated depressed BD group were apparent on tests tapping 'hot' cognitive processing, for example the Cambridge Gamble task and the Probabilistic Reversal Learning task. However, other than a deficit on the Spatial Span test in the depressed BD subjects, the groups performed equivalently on most measures of 'cold' cognitive processing, for example visual memory, attention, and working memory.

CONCLUSIONS

These data suggest that deficits on tests involving reward processing, short-term spatial memory storage, and sensitivity to negative feedback in depressed BD subjects represent an effect of the illness itself and not mood-stabilizing medication.

Neuropsychological status of bipolar I disorder: impact of psychosis

BACKGROUND

The presence of schizotypal personality traits in some people with bipolar disorder, together with reports of greater cognitive dysfunction in patients with a history of psychotic features compared with patients without such a history, raises questions about the nosological relationship between bipolar disorder with psychotic features and bipolar disorder without psychotic features.

AIMS

To test the impact of a history of DSM-IV-defined psychosis on the neuropsychological status of participants with bipolar disorder while statistically controlling for confounding factors such as mood, medication, alcohol misuse/dependence and childhood abuse, and to evaluate the impact of schizotypal personality traits (and thus potential vulnerability to psychotic illness) on the cognitive performance of people with bipolar disorder and their healthy relatives.

METHOD

Neuropsychological data were obtained for 25 participants with type I bipolar disorder and a history of psychosis, 24 with type I bipolar disorder but no history of psychosis and 61 unaffected relatives. Schizotypal traits were measured with the Schizotypal Personality Scale (STA). Childhood trauma was measured with the Childhood Trauma Questionnaire.

RESULTS

The group with a history of psychosis performed significantly worse than the healthy relatives on measures of verbal working memory, cognitive flexibility and declarative memory. Nevertheless, the two bipolar disorder groups did not differ significantly from each other on any cognitive measure. Scores on the STA were negatively associated with verbal working and declarative memory, but positively associated with visual recall memory.

CONCLUSIONS

'Psychotic' and 'non-psychotic' subtypes of bipolar disorder may lie on a nosological continuum that is most clearly defined by verbal memory impairment.

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.

Relationship between consanguinity and depression in a south Indian population

A Pilot study was Carried out to study the association of consanguinity marriage with depression. It was observed that the consanguinity of marriage was associated with depression. The odds ratio was 5.66 (CI: 2.42-13.54). The age and sex had an association with depression. The age and sex adjusted odds ratio of consanguinity marriage was 7.66 (CI: 3.93-19.45) indicating that it is independently associated with depression.