The neurocognitive performance of drug-free and medicated euthymic bipolar patients do not differ

A comparison of the social cognition and neurocognitive characteristics of adolescents with suicide behavior, adolescent with depression and healthy controls

INTRODUCTION

Deficits in neurocognition and social-cognition have been suggested to be an endophenotype for suicidal behavior. We aimed to compare the social-cognition and neurocognitive characteristics of adolescents diagnosed with depression with and without suicidal behavior and to investigate whether these functions predict suicide.

METHOD

Adolescents diagnosed with Major Depressive Disorder (MDD) with suicidal behavior (n = 42); MDD without suicidal behavior (n = 44) and age- and sex-matched controls (n = 43) were included. The University of Pennsylvania Computerized Neurobehavioral Test Battery and Autism Spectrum Screening Questionnaire (ASSQ) were used to evaluate social-cognition and neurocognitive characteristics.

RESULTS

Several neurocognitive domain values of MDD groups, were significantly different from the control group. Neutral emotion recognition task (p = 0.025) and ASSQ scores were found to be significantly impaired in the patient groups (p < 0.001). Logistic regression analysis showed that, only the increase in the Suicide Probability Scale score was found to be significant as a risk factor predicting suicide (p = 0.007, OR: 1.246).

CONCLUSION

While the neurocognitive and social-cognitive performances of adolescents with MDD were significantly lower than the control group, these performances in the two depression groups were similar. When the predictors of suicidal behavior were examined, it was found that only the increase in suicidal ideation scores predicted suicide.

The Attentional Boost Effect in Young and Adult Euthymic Bipolar Patients and Healthy Controls

In the Attentional Boost Effect (ABE), stimuli encoded with to-be-responded targets are later recognized more accurately than stimuli encoded with to-be-ignored distractors. While this effect is robust in young adults, evidence regarding healthy older adults and clinical populations is sparse. The present study investigated whether a significant ABE is present in bipolar patients (BP), who, even in the euthymic phase, suffer from attentional deficits, and whether the effect is modulated by age. Young and adult euthymic BP and healthy controls (HC) presented with a sequence of pictures paired with target or distractor squares were asked to pay attention to the pictures and press the spacebar when a target square appeared. After a 15-min interval, their memory of the pictures was tested in a recognition task. The performance in the detection task was lower in BP than in HC, in both age groups. More importantly, neither young nor adult BP exhibited a significant ABE; for HC, a robust ABE was only found in young participants. The results suggest that the increase in the attentional demands of the detection task in BP and in adult HC draws resources away from the encoding of target-associated stimuli, resulting in elimination of the ABE. Clinical implications are discussed.

Neuropsychology of Bipolar Disorder

Bipolar disorder is associated with significant dysfunction in a broad range of neuropsychological domains and processes. Deficits have been reported to occur in symptomatic states (depression, [hypo]mania) as well as in remission (euthymia), having consequences for psychological well-being and social and occupational functioning. The profile and magnitude of neuropsychological deficits in bipolar disorder have been explored in a number of systematic reviews and meta-analyses. After discussing these briefly, this chapter will focus on examining the clinical and demographic factors that influence and modify the pattern and magnitude of deficits, as well as reviewing methods of assessment and analysis approaches which may improve our understanding of these problems.

Neurocognitive impairment and evidence-based treatment options in Bipolar disorder

BACKGROUND

The current paper briefly summarizes the literature on the neurocognitive deficit and its treatment in BD patients.

METHODS

The material was chosen on the basis of previous systematic reviews the author has taken part in.

RESULTS

The data so far suggest that the deficit is qualitatively similar but quantitatively milder in comparison to schizophrenia, it is present already since the first episode, is weakly related to mood symptoms and somewhat stronger to psychotic symptoms, it probably determines much of the disability and treatment is problematic. This deficit is also present during periods of euthymia. The possible adverse effect of psychotropic medication is rather small if any at all and is confounded by the specific clinical symptoms, for which medication is used for their treatment. This is especially true concerning antipsychotics and psychotic symptoms. The origin and the etiopathogenesis of the core neurocognitive impairment remain elusive. The presence of a neurodegenerative and of a neurodevelopmental component has both data in favor and against and they are both the focus of debate.

CONCLUSIONS

Treatment of the neurocognitive deficit and restoration of functioning is problematic. The data are limited and treatment options are few and with a weak overall effect. Pharmacological treatments, ECT and rTMS present some hard data, while the literature is inconclusive concerning psychotherapeutic interventions.

Neuroanatomical Dysconnectivity Underlying Cognitive Deficits in Bipolar Disorder

BACKGROUND

Graph theory applied to brain networks is an emerging approach to understanding the brain's topological associations with human cognitive ability. Despite well-documented cognitive impairments in bipolar disorder (BD) and recent reports of altered anatomical network organization, the association between connectivity and cognitive impairments in BD remains unclear.

METHODS

We examined the role of anatomical network connectivity derived from T1- and diffusion-weighted magnetic resonance imaging in impaired cognitive performance in individuals with BD (n = 32) compared with healthy control individuals (n = 38). Fractional anisotropy- and number of streamlines-weighted anatomical brain networks were generated by mapping constrained spherical deconvolution-reconstructed white matter among 86 cortical/subcortical bilateral brain regions delineated in the individual's own coordinate space. Intelligence and executive function were investigated as distributed functions using measures of global, rich-club, and interhemispheric connectivity, while memory and social cognition were examined in relation to subnetwork connectivity.

RESULTS

Lower executive functioning related to higher global clustering coefficient in participants with BD, and lower IQ performance may present with a differential relationship between global and interhemispheric efficiency in individuals with BD relative to control individuals. Spatial recognition memory accuracy and response times were similar between diagnostic groups and associated with basal ganglia and thalamus interconnectivity and connectivity within extended anatomical subnetworks in all participants. No anatomical subnetworks related to episodic memory, short-term memory, or social cognition generally or differently in BD.

CONCLUSIONS

Results demonstrate selective influence of subnetwork patterns of connectivity in underlying cognitive performance generally and abnormal global topology underlying discrete cognitive impairments in BD.

Understanding and managing cognitive impairment in bipolar disorder in older people

Bipolar disorder is less prevalent in older people but accounts for 8–10% of psychiatric admissions. Treating and managing bipolar disorder in older people is challenging because of medical comorbidity. We review the cognitive problems observed in older people, explore why these are important and consider current treatment options. There are very few studies examining the cognitive profiles of older people with bipolar disorder and symptomatic depression and mania, and these show significant impairments in executive function. Most studies have focused on cognitive impairment in euthymic older people: as in euthymic adults of working age, significant impairments are observed in tests of attention, memory and executive function/processing speeds. Screening tests are not always helpful in euthymic older people as the impairment can be relatively subtle, and more in-depth neuropsychological testing may be needed to show impairments. Cognitive impairment may be more pronounced in older people with ‘late-onset’ bipolar disorder than in those with ‘early-onset’ disorder. Strategies to address symptomatic cognitive impairment in older people include assertive treatment of the mood disorder, minimising drugs that can adversely affect cognition, optimising physical healthcare and reducing relapse rates.

LEARNING OBJECTIVES

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DECLARATION OF INTEREST

B.J.S. consults for Cambridge Cognition, PEAK (www.peak.net) and Mundipharma.

Potential biomarkers for bipolar disorder: Where do we stand?

Bipolar disorder (BD) is a severe, recurrent mood disorder, associated with a significant morbidity and mortality, with high rates of suicides and medical comorbidities. There is a high risk of mood disorders among the first-degree relatives of patients with BD. In the current clinical practice, the diagnosis of BD is made by history taking, interview and behavioural observations, thereby lacking an objective, biological validation. This approach may result in underdiagnosis, misdiagnosis and eventually poorer outcomes. Due to the heterogeneity of BD, the possibility of developing a single, specific biomarker is still remote; however, there is a set of promising biomarkers which may serve as predictive, prognostic or treatment markers in the future. The review presents a critical appraisal and update on some of the most promising candidates for biomarkers, namely, neuroimaging markers, peripheral biomarkers and genetic markers, including a brief discussion on cognitive endophenotypes as indicative of genetic risk. The lessons learnt from other fields and specialties in medicine need to be applied to psychiatry to translate the knowledge from ‘bench to bedside’ by means of clinically useful biomarkers. Overall, the biomarkers may help in pushing the shift towards personalized medicine for psychiatric patients.

Canadian Network for Mood and Anxiety Treatments (CANMAT) and International Society for Bipolar Disorders (ISBD) 2018 guidelines for the management of patients with bipolar disorder

The Canadian Network for Mood and Anxiety Treatments (CANMAT) previously published treatment guidelines for bipolar disorder in 2005, along with international commentaries and subsequent updates in 2007, 2009, and 2013. The last two updates were published in collaboration with the International Society for Bipolar Disorders (ISBD). These 2018 CANMAT and ISBD Bipolar Treatment Guidelines represent the significant advances in the field since the last full edition was published in 2005, including updates to diagnosis and management as well as new research into pharmacological and psychological treatments. These advances have been translated into clear and easy to use recommendations for first, second, and third- line treatments, with consideration given to levels of evidence for efficacy, clinical support based on experience, and consensus ratings of safety, tolerability, and treatment-emergent switch risk. New to these guidelines, hierarchical rankings were created for first and second- line treatments recommended for acute mania, acute depression, and maintenance treatment in bipolar I disorder. Created by considering the impact of each treatment across all phases of illness, this hierarchy will further assist clinicians in making evidence-based treatment decisions. Lithium, quetiapine, divalproex, asenapine, aripiprazole, paliperidone, risperidone, and cariprazine alone or in combination are recommended as first-line treatments for acute mania. First-line options for bipolar I depression include quetiapine, lurasidone plus lithium or divalproex, lithium, lamotrigine, lurasidone, or adjunctive lamotrigine. While medications that have been shown to be effective for the acute phase should generally be continued for the maintenance phase in bipolar I disorder, there are some exceptions (such as with antidepressants); and available data suggest that lithium, quetiapine, divalproex, lamotrigine, asenapine, and aripiprazole monotherapy or combination treatments should be considered first-line for those initiating or switching treatment during the maintenance phase. In addition to addressing issues in bipolar I disorder, these guidelines also provide an overview of, and recommendations for, clinical management of bipolar II disorder, as well as advice on specific populations, such as women at various stages of the reproductive cycle, children and adolescents, and older adults. There are also discussions on the impact of specific psychiatric and medical comorbidities such as substance use, anxiety, and metabolic disorders. Finally, an overview of issues related to safety and monitoring is provided. The CANMAT and ISBD groups hope that these guidelines become a valuable tool for practitioners across the globe.

Cognitive Impairment in Bipolar Disorder: Treatment and Prevention Strategies

Over the last decade, there has been a growing appreciation of the importance of identifying and treating cognitive impairment associated with bipolar disorder, since it persists in remission periods. Evidence indicates that neurocognitive dysfunction may significantly influence patients' psychosocial outcomes. An ever-increasing body of research seeks to achieve a better understanding of potential moderators contributing to cognitive impairment in bipolar disorder in order to develop prevention strategies and effective treatments. This review provides an overview of the available data from studies examining treatments for cognitive dysfunction in bipolar disorder as well as potential novel treatments, from both pharmacological and psychological perspectives. All these data encourage the development of further studies to find effective strategies to prevent and treat cognitive impairment associated with bipolar disorder. These efforts may ultimately lead to an improvement of psychosocial functioning in these patients.

Cognitive profiles in euthymic patients with bipolar disorders: results from the FACE-BD cohort

OBJECTIVES

Although cognitive deficits are a well-established feature of bipolar disorders (BD), even during periods of euthymia, little is known about cognitive phenotype heterogeneity among patients with BD.

METHODS

We investigated neuropsychological performance in 258 euthymic patients with BD recruited via the French network of expert centers for BD. We used a test battery assessing six domains of cognition. Hierarchical cluster analysis of the cross-sectional data was used to determine the optimal number of subgroups and to assign each patient to a specific cognitive cluster. Subsequently, subjects from each cluster were compared on demographic, clinical functioning, and pharmacological variables.

RESULTS

A four-cluster solution was identified. The global cognitive performance was above normal in one cluster and below normal in another. The other two clusters had a near-normal cognitive performance, with above and below average verbal memory, respectively. Among the four clusters, significant differences were observed in estimated intelligence quotient and social functioning, which were lower for the low cognitive performers compared to the high cognitive performers.

CONCLUSIONS

These results confirm the existence of several distinct cognitive profiles in BD. Identification of these profiles may help to develop profile-specific cognitive remediation programs, which might improve functioning in BD.

Behavioral measures and self-report of impulsivity in bipolar disorder: no association between Stroop test and Barratt Impulsiveness Scale

BACKGROUND

Impulsivity as a tendency to act quickly without considering future consequences has been proposed as a dimensional factor in bipolar disorder. It can be measured using behavioral tasks and self-report questionnaires. Previous findings revealed patients to show worse performance on at least one behavioral measure of impulsivity. Additionally, self-reported impulsivity seems to be higher among bipolar patients, both parameters being possibly associated with a more severe course of illness. In this study, our primary aim was to investigate the relationship between these two constructs of impulsivity among bipolar patients.

METHODS

A total of 40 euthymic patients with bipolar disorder (21 female, 22 Bipolar I) and 30 healthy controls were recruited for comprehensive neuropsychological assessment. To assess inhibition control as a behavioral measure of impulsivity, the Stroop Color and Word Test (Stroop) was used. Additionally, both groups completed the Barratt Impulsiveness Scale (BIS) as a self-report of impulsivity. To compare the groups' performance on the Stroop and ratings on the BIS, the non-parametric Mann-Whitney U test was used. Within the bipolar group, we additionally examined the possibility of an association between Stroop performance and BIS total scores using Pearson's Correlation r.

RESULTS

Patients and controls differed significantly on the Stroop and BIS, with patients performing worse on the Stroop and scoring higher on the BIS. However, there was no association between the Stroop and BIS within the bipolar group. As an exploratory analysis, a positive correlation between Stroop performance and number of episodes was found. Further, we detected a statistical trend in the direction of poorer Stroop performance among patients treated with polypharmacy.

CONCLUSIONS

Both difficulties with behavioral inhibition and self-reported impulsivity were observed to be higher in bipolar patients than controls in the current study. However, within the patient group we did not observe an association between patients' behavioral performance and self-report. This indicates that the parameters likely constitute distinct, dimensional factors of bipolar disorder. In future research, studies with larger samples should investigate which of the two markers constitutes the better marker for the illness and is more suitable to differentiate the most severe patients.

Prevalence and correlates of cognitive impairment in euthymic adults with bipolar disorder: A systematic review

BACKGROUND

Previous reviews have identified medium-large group differences in cognitive performance in adults with bipolar disorder (BD) compared to healthy peers, but the proportion with clinically relevant cognitive impairment has not yet been established. This review aimed to quantify the prevalence of cognitive impairment in euthymic adults with BD, and to describe sociodemographic, clinical and other factors that are significantly associated with cognitive impairment.

METHODS

Systematic literature review. The population was euthymic community-dwelling adults with BD, aged 18-70 years, and recruited consecutively or randomly. The outcome was cognitive impairment, relative to healthy population norms. Electronic databases and reference lists of relevant articles were searched, and authors were contacted. Original cross-sectional studies published in peer-reviewed English-language journals from January 1994 to February 2015 were included. Methodological bias and reporting bias were assessed using standard tools. A narrative synthesis is presented together with tables and forest plots.

RESULTS

Thirty articles were included, of which 15 contributed prevalence data. At the 5th percentile impairment threshold, prevalence ranges were: executive function 5.3-57.7%; attention/working memory 9.6-51.9%; speed/reaction time 23.3-44.2%; verbal memory 8.2-42.1%; visual memory 11.5-32.9%. More severe or longstanding illness and antipsychotic medication were associated with greater cognitive impairment.

LIMITATIONS

The synthesis was limited by heterogeneity in cognitive measures and impairment thresholds, precluding meta-analysis.

CONCLUSIONS

Cognitive impairment affects a substantial proportion of euthymic adults with BD. Future research with more consistent measurement and reporting will facilitate an improved understanding of cognitive impairment burden in BD.

Abdominal obesity is associated with impaired cognitive function in euthymic bipolar individuals

OBJECTIVES

Overweight/obesity has been implicated to play a role in cognitive deficits in bipolar disorder (BD). This study aims to identify the relationship between body fat distribution and different domains of cognition in BD during euthymia.

METHODS

A sample of 100 euthymic individuals with BD was measured with a cognitive test battery (i.e., Trail Making Test-A-B/TM-A/B, d2 Test of Attention, Stroop test, California Verbal Learning Test/CVLT) and an anthropometric measures set (body mass index, waist circumference, hip circumference, waist-to-hip-ratio, waist-to-height-ratio, and lipometry). Patient data were compared with a healthy control group (n = 64).

RESULTS

Results show that overweight patients with BD exhibit lower performance in the TMT-A/B as well as in the free recall performance of the CVLT compared to normal-weight patients with BD and controls. In bipolar individuals, (abdominal) obesity was significantly associated with a poor cognitive performance. In bipolar females, associations with measures of verbal learning and memory were found; in bipolar males, associations with poor performance in the TMT-A/B and in the Stroop interference task were demonstrated. In controls, no associations were found.

CONCLUSIONS

There are several possible pathways moderating the association between obesity and cognition in BD. Anthropometric and lipometry data underline the substantial mediating impact of body fat distribution on cognition in BD.

The management of cognitive impairment in bipolar disorder: current status and perspectives

Bipolar disorder (BD) is associated with important cognitive deficits that persist during the periods of remission. Although these deficits seem to play an important role in the functional impairment experienced by bipolar patients, evidence regarding their clinical management is scant. We revised the databases PubMed, MEDLINE, and clinicaltrials.gov, searching for studies focusing on the pharmacological and nonpharmacological treatment of cognitive deficits among bipolar patients. In addition, a manual search of bibliographical cross-references was performed. Currently, there is no Food and Drug Administration-approved pharmacological agent for the management of cognitive deficits in BD. A number of agents have been tested in the treatment of cognitive deficits in BD, with mixed results. Nonpharmacological interventions, such as cognitive remediation and noninvasive brain stimulation techniques, seem promising, but their role has not yet been properly explored among bipolar patients. Additional studies, aiming at evaluating the efficacy of interventions combining cognitive rehabilitation and biological treatments, are highly desirable.

Cognitive reserve in bipolar disorder: relation to cognition, psychosocial functioning and quality of life

OBJECTIVE

Cognitive reserve (CR) is a concept that was postulated as a protective factor for some clinical symptoms after the observation that there is not a direct relationship between the degree of brain damage and its clinical manifestation. This study aimed to explore the association between CR and the main outcomes in bipolar disorder (BD): cognitive functions, psychosocial functioning and perceived quality of life.

METHOD

A sample of 224 euthymic bipolar patients was assessed with a neuropsychological battery, the Functioning Assessment Short Test and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). CR was calculated through three proxies: estimated premorbid Intelligent Quotient, educational level and occupational attainment. Relationships between CR and cognitive functions, psychosocial functioning and quality of life were assessed by multiple linear regression models.

RESULTS

Higher CR was associated with better cognitive functioning (P < 0.001 in processing speed, working memory, verbal and visual memory, and executive function; P = 0.026 in attention) and better psychosocial functioning (P = 0.008). For quality of life, CR was positively associated with the physical component of the SF-36 (P = 0.016) but negatively associated with the mental component (P = 0.004).

CONCLUSION

The results suggest that CR may play an important role in the course and prognosis of bipolar patients and it should be considered in both clinical and research settings related to BD.

Patients with bipolar disorder show differential executive dysfunctions: A case-control study

Executive deficits in euthymic bipolar I disorder were examined in a fractionated manner based on the "Supervisory Attentional System" (SAS) model, and the relationship between the degree of executive impairment and the demographic and clinical characteristics of bipolar I participants was explored. A battery of neurocognitive tests capturing specific components of executive function was administered on 30 patients with bipolar I disorder in euthymic state, and compared with 30 healthy controls who were matched by age, gender and IQ. A differential impairment in executive function was demonstrated in euthymic bipolar I participants by using a fractionated approach of the SAS. Euthymic bipolar I patients were found to have significantly poorer performance in immediate and delayed visual memory; and in the executive domains of "initiation", "sustained attention", and "attention allocation and planning". Those with a greater number of executive impairments had lower IQ and higher negative sub-scores on PANSS. These findings might provide a the basis for further studies on identifying the executive components that are associated with particular disease characteristics of bipolar disorder, and those with poorer functional outcome, so that rehabilitation can be focused on the selective domains concerned.

The Lithium Battery: assessing the neurocognitive profile of lithium in bipolar disorder

OBJECTIVE

The aim of the present study was to characterize the neurocognitive effects of lithium in bipolar disorder to inform clinical and research approaches for further investigation.

METHODS

Key words pertaining to neurocognition in bipolar disorder and lithium treatment were used to search recognized databases to identify relevant literature. The authors also retrieved gray literature (e.g., book chapters) known to them and examined pertinent articles from bibliographies.

RESULTS

A limited number of studies have examined the effects of lithium on neurocognition in bipolar disorder and, although in some domains a consistent picture emerges, in many domains the findings are mixed. Lithium administration appears to reshape key components of neurocognition - in particular, psychomotor speed, verbal memory, and verbal fluency. Notably, it has a sophisticated neurocognitive profile, such that while lithium impairs neurocognition across some domains, it seemingly preserves others - possibly those vulnerable to the effects of bipolar disorder. Furthermore, its effects are likely to be direct and indirect (via mood, for example) and cumulative with duration of treatment. Disentangling the components of neurocognition modulated by lithium in the context of a fluctuating and complex illness such as bipolar disorder is a significant challenge but one that therefore demands a stratified and systematic approach, such as that provided by the Lithium Battery.

CONCLUSIONS

In order to delineate the effects of lithium therapy on neurocognition in bipolar disorder within both research and clinical practice, a greater understanding and measurement of the relatively stable neurocognitive components is needed to examine those that indeed change with lithium treatment. In order to achieve this, we propose a Lithium Battery-Clinical and a Lithium Battery-Research that can be applied to these respective settings.

Comparative neurocognitive effects of lithium and anticonvulsants in long-term stable bipolar patients

BACKGROUND

The aim of choosing a mood-stabilizing drug (lithium or anticonvulsants) or a combination of them with minimal neurocognitive effects is to stimulate the development of criteria for a therapeutic adequacy, particularly in Bipolar Disorder (BD) patients who are clinically stabilized.

METHOD

Three groups of BD patients were established according to their treatment: (i) lithium monotherapy (n=29); (ii) lithium together with one or more anticonvulsants (n=28); and (iii) one or more anticonvulsants (n=16). A group of healthy controls served as the control (n=25). The following tests were applied: Wechsler Adult Intelligence Scale, Trail Making Test, Wechsler Memory Scale, Rey Complex Figure Test, Stroop color-word test, Wisconsin Card Sorting Test, Tower of Hanoi, Frontal Assessment Battery, and Reading the Mind in the Eyes Test.

RESULTS

Relative to healthy controls, BD patients showed the following: (i) those on lithium monotherapy, but not other BD groups, had preserved short-term auditory memory, long-term memory, and attention; (ii) those who took only anticonvulsants showed worse findings in short-term visual memory, working memory, and several executive functions; and (iii) all BD patients showed worse performance in processing speed, resistance to interference, and emotion recognition.

LIMITATIONS

Medication alone cannot explain why all BD patients showed common cognitive deficits despite different pharmacological treatment.

CONCLUSION

The impairment on some executive functions and emotion recognition is an inherent trait in BD patients, regardless of their pharmacological treatment. However, while memory, attention, and most of the executive functions are preserved in long-term stable BD patients, these cognitive functions are impaired in those who take anticonvulsants.

Neurocognitive intra-individual variability in mood disorders: effects on attentional response time distributions

BACKGROUND

Attentional impairment is a core cognitive feature of major depressive disorder (MDD) and bipolar disorder (BD). However, little is known of the characteristics of response time (RT) distributions from attentional tasks. This is crucial to furthering our understanding of the profile and extent of cognitive intra-individual variability (IIV) in mood disorders.

METHOD

A computerized sustained attention task was administered to 138 healthy controls and 158 patients with a mood disorder: 86 euthymic BD, 33 depressed BD and 39 medication-free MDD patients. Measures of IIV, including individual standard deviation (iSD) and coefficient of variation (CoV), were derived for each participant. Ex-Gaussian (and Vincentile) analyses were used to characterize the RT distributions into three components: mu and sigma (mean and standard deviation of the Gaussian portion of the distribution) and tau (the 'slow tail' of the distribution).

RESULTS

Compared with healthy controls, iSD was increased significantly in all patient samples. Due to minimal changes in average RT, CoV was only increased significantly in BD depressed patients. Ex-Gaussian modelling indicated a significant increase in tau in euthymic BD [Cohen's d = 0.39, 95% confidence interval (CI) 0.09-0.69, p = 0.011], and both sigma (d = 0.57, 95% CI 0.07-1.05, p = 0.025) and tau (d = 1.14, 95% CI 0.60-1.64, p < 0.0001) in depressed BD. The mu parameter did not differ from controls.

CONCLUSIONS

Increased cognitive variability may be a core feature of mood disorders. This is the first demonstration of differences in attentional RT distribution parameters between MDD and BD, and BD depression and euthymia. These data highlight the utility of applying measures of IIV to characterize neurocognitive variability and the great potential for future application.

Impaired conflict resolution and vigilance in euthymic bipolar disorder

Difficulty attending is a common deficit of euthymic bipolar patients. However, it is not known whether this is a global attentional deficit or relates to a specific attentional network. According to the attention network approach, attention is best understood in terms of three functionally and neuroanatomically distinct networks-alerting, orienting, and executive control. In this study, we explored whether and which of the three attentional networks are altered in euthymic Bipolar Disorder (BD). A sample of euthymic BD patients and age-matched healthy controls completed the Attention Network Test for Interactions and Vigilance (ANTI-V) that provided not only a measure of orienting, executive, and alerting networks, but also an independent measure of vigilance (tonic alerting). Compared to healthy controls, BD patients have impaired executive control (greater interference), reduced vigilance (as indexed by a decrease in the d' sensitivity) as well as slower overall reaction times and poorer accuracy. Our results show that deficits in executive attention and sustained attention often persist in BD patients even after complete remission of affective symptoms, thus suggesting that cognitive enhancing treatments programmed to improve these deficits could contribute to improve their functional recovery.

Verbal memory impairment in new onset bipolar disorder: Relationship with frontal and medial temporal morphology

OBJECTIVES

Verbal memory (VM) impairment is a trait feature of bipolar I disorder (BDI) that is present at illness onset and associated with functional outcome. However, little is known about the morphological abnormalities underlying this deficit early in the disease course. This study examined the neurobiological correlates of VM impairment in euthymic newly diagnosed patients, with attention to frontal and medial temporal (MT) structures known to contribute to VM.

METHODS

Euthymic patients with BDI recently recovered from their first episode of mania (n = 42) were compared with healthy subjects (n = 37) using measures of the California Verbal Learning Test (CVLT-II) associated with frontal and MT functioning. A subset of participants had 3T MRI scan (n = 31 patient group, n = 30 healthy subject group). Hippocampal and prefrontal volumes were analyzed using FreeSurfer 5.1 and correlated with their corresponding CVLT-II subscores.

RESULTS

Patients showed decreased performance in total learning as well as short and long delay verbal recall. Consistent with MT dysfunction, they also showed deficits in recognition discriminability and learning slope. In the patient group only, left hippocampal volumes were negatively correlated with these measures.

CONCLUSIONS

These results suggest that anomalous MT functioning is involved with VM impairment early in the course of BDI.

Fractionation of visuo-spatial memory processes in bipolar depression: a cognitive scaffolding account

BACKGROUND

Previous studies of neurocognitive performance in bipolar disorder (BD) have demonstrated impairments in visuo-spatial memory. The aim of the present study was to use an object-location memory (OLM) paradigm to assess specific, dissociable processes in visuo-spatial memory and examine their relationship with broader neurocognitive performance.

METHOD

Fifty participants (25 patients with BD in a current depressive episode and 25 matched healthy controls) completed the OLM paradigm which assessed three different aspects of visuo-spatial memory: positional memory, object-location binding, and a combined process. Secondary neurocognitive measures of visuo-spatial memory, verbal memory, attention and executive function were also administered.

RESULTS

BD patients were significantly impaired on all three OLM processes, with the largest effect in exact positional memory (d = 1.18, p < 0.0001). General deficits were also found across the secondary neurocognitive measures. Using hierarchical regression, verbal learning was found to explain significant variance on the OLM measures where object-identity was present (the object-location binding and combined processes) and accounted for the group difference. The group difference in precise positional memory remained intact.

CONCLUSIONS

This study demonstrates that patients with bipolar depression manifest deficits in visuo-spatial memory, with substantial impairment in fine-grain, positional memory. The differential profile of processes underpinning the visuo-spatial memory impairment suggests a form of 'cognitive scaffolding', whereby performance on some measures can be supported by verbal memory. These results have important implications for our understanding of the functional cognitive architecture of mood disorder.

Evidence for cognitive subgroups in bipolar disorder and the influence of subclinical depression and sleep disturbances

Recent research in bipolar disorder (BD) points to the relevance and persistence of cognitive deficits even in euthymia. Up to now, the mechanisms behind why some bipolar patients (BP) do not reach their former level of cognitive performance and psychosocial functioning while others remit completely, are not understood. In this study we aimed to identify a "cognitive deficit" vs. "non-deficit" subgroup within BD by using an extensive neuropsychological test battery. The test performance of 70 euthymic outpatients (BD-I and II, recruited as a sample of convenience from our bipolar disorder programme) was compared to 70 matched, healthy controls (HC). Furthermore, we investigated the association between demographic/clinical variables and the cognitive performance of BP. As expected, our sample of euthymic BP performed significantly worse than HC in psychomotor speed, divided attention, working memory, verbal memory, word fluency and problem solving. However, 41.4% of the patients did not have any neurocognitive deficits at all, and whether or not a patient belonged to the non-deficit group was not influenced by disease severity. Instead, our results demonstrate that patients suffering from persistent sleep disturbances and sub-threshold depressive symptomatology show more severe cognitive dysfunctions. In addition, antipsychotic treatment and comorbid anxiety disorder were associated with cognitive deficits. In sum, these results suggest that a major part of cognitive impairment is due to current symptomatology, especially sleep disorder and sub-syndromal depression. Rigorous treatment of these symptoms thus might well improve cognitive deficits and, as a consequence, overall functioning in BD.

The neurocognitive functioning in bipolar disorder: a systematic review of data

BACKGROUND

During the last decades, there have been many different opinions concerning the neurocognitive function in Bipolar disorder (BD). The aim of the current study was to perform a systematic review of the literature and to synthesize the data in a comprehensive picture of the neurocognitive dysfunction in BD.

METHODS

Papers were located with searches in PubMed/MEDLINE, through June 1st 2015. The review followed a modified version of the recommendations of the Preferred Items for Reporting of Systematic Reviews and Meta-Analyses statement.

RESULTS

The initial search returned 110,403 papers. After the deletion of duplicates, 11,771 papers remained for further evaluation. Eventually, 250 were included in the analysis.

CONCLUSION

The current review supports the presence of a neurocognitive deficit in BD, in almost all neurocognitive domains. This deficit is qualitative similar to that observed in schizophrenia but it is less severe. There are no differences between BD subtypes. Its origin is unclear. It seems it is an enduring component and represents a core primary characteristic of the illness, rather than being secondary to the mood state or medication. This core deficit is confounded (either increased or attenuated) by the disease phase, specific personal characteristics of the patients (age, gender, education, etc.), current symptomatology and its treatment (especially psychotic features) and long-term course and long-term exposure to medication, psychiatric and somatic comorbidity and alcohol and/or substance abuse.

Role of adverse effects in medication nonadherence in bipolar disorder

Nonadherence to medications is common and associated with poor or limited clinical outcomes in the treatment of bipolar disorder. A review of the literature discloses that adverse effects are one of the commonly reported reasons for nonadherence to mood stabilizers by patients with bipolar disorder. Nevertheless, other than such broad summaries, relatively little attention has been given to the role of adverse effects in relation to nonadherence. This review article is the first to consolidate the available data on this topic. Weight gain, perceived cognitive impairment, tremors, and sedation are the adverse effects most likely to lead to nonadherence. Further research is needed to anticipate, identify, manage, and potentially minimize the impact of adverse effects.

The role of encoding strategies in contextual memory deficits in patients with bipolar disorder

Contextual memory is important for the encoding and retrieval of episodic memory, which is often impaired in euthymic patients with bipolar disorder (BD). The objective was to investigate the effect of low and high cognitive support on encoding in an incidental contextual memory task in euthymic patients with BD. Twenty-three patients with a BD type I diagnosis (aged 23-63 years, 17 women and 6 men) and 29 healthy controls completed a recognition memory task for context (location of a recognised object). Participants were assigned to one of two incidental encoding conditions: (1) with a binding cue to encourage the association of the object to its location (judging the degree of appropriateness of an object in relation to its location) or (2) without a binding cue (judging daily use of objects). Patients showed a deficit in incidental contextual memory in the absence of a binding cue at encoding. Under incidental encoding with the binding cue, no differences were observed between the groups for contextual memory. Contextual memory deficits in BD patients were reduced by providing cognitive support at encoding. The role of this strategy should be investigated in larger samples to evaluate its use for cognitive remediation in BD patients.

Sustained attention in psychosis: Neuroimaging findings

To provide a systematic review of scientific literature on functional magnetic resonance imaging (fMRI) studies on sustained attention in psychosis. We searched PubMed to identify fMRI studies pertaining sustained attention in both affective and non-affective psychosis. Only studies conducted on adult patients using a sustained attention task during fMRI scanning were included in the final review. The search was conducted on September 10^th, 2013. 15 fMRI studies met our inclusion criteria: 12 studies were focused on Schizophrenia and 3 on Bipolar Disorder Type I (BDI). Only half of the Schizophrenia studies and two of the BDI studies reported behavioral abnormalities, but all of them evidenced significant functional differences in brain regions related to the sustained attention system. Altered functioning of the insula was found in both Schizophrenia and BDI, and therefore proposed as a candidate trait marker for psychosis in general. On the other hand, other brain regions were differently impaired in affective and non-affective psychosis: alterations of cingulate cortex and thalamus seemed to be more common in Schizophrenia and amygdala dysfunctions in BDI. Neural correlates of sustained attention seem to be of great interest in the study of psychosis, highlighting differences and similarities between Schizophrenia and BDI.

Neurocognitive functioning in bipolar depression: a component structure analysis

BACKGROUND

Previous studies of neurocognitive performance in bipolar disorder (BD) have focused predominantly on euthymia. In this study we aimed to compare the neurocognitive profile of BD patients when depressed with healthy controls and explore the component structure of neurocognitive processes in these populations.

METHOD

Cognitive tests of attention and executive function, immediate memory, verbal and visuospatial learning and memory and psychomotor speed were administered to 53 patients with a SCID-verified diagnosis of BD depression and 47 healthy controls. Test performance was assessed in terms of statistical significance, effect size and percentile standing. Principal component analysis (PCA) was used to explore underlying cognitive factor structure.

RESULTS

Multivariate analysis revealed an overall group effect, depressed BD patients performing significantly worse than controls. Patients performed significantly worse on 18/26 measures examined, with large effect sizes (d > 0.8) on tests of speed of processing, verbal learning and specific executive/working memory processes. Almost all tests produced at least one outcome measure on which ∼25-50% of the BD sample performed at more than 1 standard deviation (s.d.) below the control mean. Between 20% and 34% of patients performed at or below the fifth percentile of the control group in working memory, verbal learning and memory, and psychomotor/processing speed. PCA highlighted overall differences between groups, with fewer extracted components and less specificity in patients.

CONCLUSIONS

Overall, neurocognitive test performance is significantly reduced in BD patients when depressed. The use of different methods of analysing cognitive performance is highlighted, along with the relationship between processes, indicating important directions for future research.

Longitudinal study of sustained attention in outpatients with bipolar disorder

Individuals with bipolar disorder (BD) may exhibit attentional deficits, however, the extent of impairment and long-term fluctuations in performance in attention are relatively unknown. We investigated the relationship between sustained attention and affective symptoms over time among BD patients. We also examined whether global differences in attentional capacity differed among BD versus normal comparison (NC) subjects. Participants included 106 outpatients with BD and 66 NC subjects who were administered symptom rating scales and a measure of sustained attention (Continuous Performance Test- Identical Pairs). Measures were repeated 6, 12, and 26 weeks post-baseline. Compared to NC subjects, participants with BD showed impairment in sustained attention across time. Within patient increases in manic symptoms were associated with increased false alarms; both manic and depressive symptoms were associated with worse discrimination. Neither manic nor depressive symptoms were related to hit rates. Our results indicate that the ability to inhibit a response to near miss stimuli (i.e., those that are close to but not identical to the target) is globally impaired among BD patients relative to NC subjects, as well as state-dependent, covarying with affective symptoms. Psychosocial interventions requiring high levels of attentional capacity may need to be adapted according to patients' current symptomatology.

Overgenerality memory style for past and future events and emotions related in bipolar disorder. What are the links with problem solving and interpersonal relationships?

This study investigated patients with Bipolar Disorder's abilities to generate specific past and future events in response to positive and negative cues words as well as emotional intensity related to these ones. The relationships between the number of generated specific events cognitive functioning, interpersonal problems and the ability to problem solving were investigated. Nineteen BD and nineteen healthy controls completed a French version of the AMT to evaluate the past and future events recall, in function of their valence, and emotions related. Furthermore, they completed the Optional Thinking Test, the Inventory of Interpersonal Problems and the neuropsychological measures. Compared to healthy controls, BD recollected (1) fewer specific past negative events and (2) fewer future specific positive and negative events furthermore, (3) they felt more emotional intensity related to future events. These results were explained in the light of theoretical models. Finally, specific past memories deficits in BD were linked with issues in problem solving but not with levels of distress arising from interpersonal problems. In view of AM functions in everyday life, all types of deficits should be taken into consideration, and AM remediation envisaged.

Performance monitoring and executive control of attention in euthymic bipolar disorder: employing the CPT-AX paradigm

Reduced cognitive test performance has been demonstrated in patients with bipolar disorder (BD), even when euthymic. Several studies have explored aspects of attention, including sustained attention, and reported patients show lower accuracy compared to controls. It is necessary to modify existing attentional paradigms to fully characterise such deficits. The present study sought to examine if there are changes in the profile of performance and error-types during a sustained attention task in BD. Twenty-two euthymic patients with DSM-IV diagnosed BD and 21 healthy controls were recruited. Participants completed a modified CPT-AX paradigm with a high proportion of target trials (70%) with cues and probes presented at continuous intervals. This modification increases the demands on response inhibition and permits the deconstruction of attentional/executive deficits previously described. Overall, BD patients showed significantly poorer target discriminability compared to controls. In block one (first quarter) of the task, patients showed no significant differences to controls, but by the final fourth block (last quarter) they made significantly fewer hits and more errors (both 'AX' misses and 'BX' false alarms). BD patients completed initial stages of the task similarly to controls, but as demands on the attentional system continued difficulties emerged, consistent with problems in context-maintenance.

Executive deficits: a continuum schizophrenia-bipolar disorder or specific to schizophrenia?

Executive dysfunction is a core deficit in schizophrenia (SCH). However, some controversy exists when examining such deficits in studies of bipolar disorder (BD). The aim of the present research was to investigate whether executive deficits were similar or distinct in both illnesses. 148 patients with BD, 262 patients with stable SCH and 108 healthy controls (CT) were recruited for the study. The BD patients were also differentiated according to the clinical subtype (BD subtype I, BDI, or subtype II, BDII) they exhibited and according to whether there was a previous history of psychosis. All subjects completed a broad neuropsychological battery. The influences of other clinical data were also evaluated. Both the BD and SCH patients showed widespread deficits in all executive tasks, with no differences between these two groups of patients. BDII patients only showed some selective deficits, and their scores on planning and inhibitory tasks fell on the continuum between the CT, the BDI and the SCH patients. Psychotic phenotypes did not influence the BD patients' performance on the battery. Other clinical variables related to illness severity did influence deficits in any subgroup of patients. Our results point to the existence of common executive disturbances in both diagnostic categories. Moreover, the inclusion of subclinical phenotypes in research may be helpful in cognitive assessment studies.

Neuropsychological testing of cognitive impairment in euthymic bipolar disorder: an individual patient data meta-analysis

OBJECTIVE

An association between bipolar disorder and cognitive impairment has repeatedly been described, even for euthymic patients. Findings are inconsistent both across primary studies and previous meta-analyses. This study reanalysed 31 primary data sets as a single large sample (N = 2876) to provide a more definitive view.

METHOD

Individual patient and control data were obtained from original authors for 11 measures from four common neuropsychological tests: California or Rey Verbal Learning Task (VLT), Trail Making Test (TMT), Digit Span and/or Wisconsin Card Sorting Task.

RESULTS

Impairments were found for all 11 test-measures in the bipolar group after controlling for age, IQ and gender (Ps ≤ 0.001, E.S. = 0.26-0.63). Residual mood symptoms confound this result but cannot account for the effect sizes found. Impairments also seem unrelated to drug treatment. Some test-measures were weakly correlated with illness severity measures suggesting that some impairments may track illness progression.

CONCLUSION

This reanalysis supports VLT, Digit Span and TMT as robust measures of cognitive impairments in bipolar disorder patients. The heterogeneity of some test results explains previous differences in meta-analyses. Better controlling for confounds suggests deficits may be smaller than previously reported but should be tracked longitudinally across illness progression and treatment.

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.

Impaired sustained attention in euthymic bipolar disorder patients and non-affected relatives: an fMRI study

OBJECTIVE

Behavioral deficits in sustained attention have been reported during both acute and euthymic phases of type I bipolar disorder (BD-I) and also in non-affected relatives of bipolar disorder (BD) patients. In particular, selective failure in target recognition was proposed as a potential trait marker for BD, but there are few studies exploring the neural correlates. The aim of the present study was to analyze the behavioral and functional magnetic resonance imaging (fMRI) response of euthymic BD-I patients and non-affected relatives during a sustained attention task.

METHODS

Twenty-four euthymic BD-I patients, 22 non-affected first-degree relatives of BD-I subjects, and 24 matched controls underwent a continuous performance test (CPT) with two levels of difficulty during event-related fMRI scanning.

RESULTS

Both patients and relatives showed a lower accuracy in target detection when compared to controls. The fMRI data analysis revealed between-group differences in several brain regions involved in sustained attention. During error in target recognition, both patients and relatives showed a larger activation in the bilateral insula and the posterior part of the middle cingulate cortex. By contrast, during correct target response, only patients failed to activate the right insula, whereas relatives showed an increased activation of the left insula and bilateral inferior parietal lobule - limited to the higher attention load - and an augmented deactivation of the posterior cingulate/retrosplenial cortex.

CONCLUSIONS

A selective impairment in target recognition during a CPT was behaviorally and functionally detectable in both euthymic BD-I patients and non-affected first-degree relatives, suggesting that specific sustained attention deficits may be a potential trait marker for BD-I.

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.

The cumulative load of depressive illness is associated with cognitive function in the remitted state of unipolar depressive disorder

OBJECTIVE

To investigate whether the cumulative number, duration and subtypes (severity and presence of psychotic features) of previous episodes of depression in patients with unipolar depressive disorder in a remitted state are associated with decreased global cognitive function.

METHODS

Via the Danish registers individuals between 40 and 80 years of age were identified: (1) patients with a diagnosis of unipolar disorder at their first discharge from a psychiatric hospital in the period 1994 to 2002, and (2) gender and age matched control individuals. The participants were assessed with the Cambridge Cognitive Examination (CAMCOG), which provides a composite measure of global cognitive function.

RESULTS

A total of 88 patients and 50 controls accepted our invitation to participate, fulfilled the selection criteria and were included in the study. The cumulative duration of depressive episodes was associated with a decreased CAMCOG score adjusted for age, gender, education, premorbid IQ and residual depressive symptoms (B=-0.14, 95% C.I. (-0.26, -0.02), R(2)adj=0.31, P=.02). Significant associations were also found between CAMCOG score and the cumulative duration and total number of depressive episodes with psychotic features, respectively.

CONCLUSION

Our findings suggest that cognitive dysfunction is associated with the cumulative duration of depressive episodes, and that, in particular, depressive episodes with psychotic features in the course of illness may be a significant predictor of future impairment of cognitive function.

Social cognition in euthymic bipolar disorder: systematic review and meta-analytic approach

OBJECTIVE

Deficits in social cognition have been reported in euthymic subjects with bipolar disorder (BD). However, some studies have failed to find differences favoring controls. As most investigations have been conducted with small samples, they have not had sufficient power to detect statistically significant differences. Furthermore, studies communicating positive results have scarcely attempted to estimate effect sizes for patient-control differences. The aim of this study was to summarize the findings of reports on social cognition in patients with euthymic BD and to combine their data to identify possible deficits and quantify their magnitude.

METHOD

Systematic literature review and meta-analysis.

RESULTS

Impairments of moderate magnitude (0.5 < d < 0.8) were noted across mentalizing skills, whereas small but significant effect sizes (d < 0.5) were observed for facial emotion recognition. No patient-control differences were found for decision-making.

CONCLUSION

Meta-analytic findings provide evidence for emotion processing and theory of mind deficits in remitted bipolar patients. However, it is not yet clear whether these areas of impairment are related to neurocognitive dysfunctions or to medication effects. The results are discussed with regard to targets for future neuropsychological research on BDs.

Functional MRI correlates of visuospatial planning in out-patient depression and anxiety

OBJECTIVE

Major depressive disorder (MDD) has been associated with executive dysfunction and related abnormal prefrontal activity, whereas the status of executive function (EF) in frequently co-occurring anxiety disorders and in comorbid depression-anxiety is unclear. We aimed to study functional MRI correlates of (visuospatial) planning in MDD and anxiety disorders and to test for the effects of their comorbidity.

METHOD

Functional MRI was employed during performance of a parametric Tower of London task in out-patients with MDD (n = 65), MDD with comorbid anxiety (n = 82) or anxiety disorders without MDD (n = 64), and controls (n = 63).

RESULTS

Moderately/severely depressed patients with MDD showed increased left dorsolateral prefrontal activity as a function of task load, together with subtle slowing during task execution. In mildly depressed and remitted MDD patients, in anxiety patients, and in patients with comorbid depression-anxiety, task performance was normal and no activation differences were observed. Medication use and regional brain volume were not associated with altered visuospatial planning.

CONCLUSION

Prefrontal hyperactivation during high planning demands is not a trait characteristic, but a state characteristic of MDD without comorbid anxiety, occurring independent of SSRI use. Disturbances in planning or the related activation are probably not a feature of anxiety disorders with or without comorbid MDD, supporting the current distinction between anxiety disorders and depression.

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.

The 5-HTTLPR polymorphism, impulsivity and suicide behavior in euthymic bipolar patients

BACKGROUND

Suicide behavior is very frequent in Bipolar Disorder (BD) and they are both closely associated with impulsivity. Furthermore they are, impulsivity, BD and suicide behavior, associated with serotonergic function, at least partially, under genetic determinism and somewhat associated with the serotonin transporter gene polymorphism, the 5-HTTLPR. We aimed to assess different impulsivity components in BD sub-grouped by suicidal attempt and healthy controls. We hypothesized that the non-planning/cognitive impulsivity, could be more closely associated with suicidal behavior. We further associated 5-HTTLPR genotypes with neuropsychological results to test the hypothesis that this polymorphism is associated with cognitive impulsivity.

METHOD

We assessed 95 euthymic bipolar patients sub-grouped by suicidal attempt history in comparison with 94 healthy controls. All subjects underwent a laboratory assessment of impulsivity (Continuous Performance Test and Iowa Gambling Test). Furthermore the genotyping of 5-HTTLPR was performed in all subjects.

RESULTS

We found that bipolar patients are more impulsive than healthy controls in all impulsivity dimensions we studied. Furthermore bipolar patients with a suicide attempt history have a greater cognitive impulsivity when compared to both bipolar patients without such a history as well when compared to healthy controls. No association was found between 5-HTTLPR genotypes and neuropsychological measures of impulsive behavior.

LIMITATIONS

The sample studied can be considered small and a potentially confounding variable - medication status - was not controlled.

CONCLUSION

A lifetime suicide attempt seems associated with cognitive impulsivity independently of the socio-demographic and clinical variables studied as well with 5-HTTLPR genotype. Further studies in larger samples are necessary.

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 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.

Neurocognitive and neuroimaging predictors of clinical outcome in bipolar disorder

Historically, bipolar disorder has been conceptualized as a disease involving episodic rather than chronic dysfunction. However, increasing evidence indicates that bipolar disorder is associated with substantial inter-episode psychosocial and vocational impairment. Here we review the contributions of neurocognitive deficits and structural and functional neuroanatomic alterations to the observed functional impairments. In particular, compelling evidence now suggests that neurocognitive impairments, particularly in the areas of attention, processing speed, and memory, are associated with functional outcome. Although investigation of the neural correlates of functional disability in bipolar disorder is only in its nascent stages, preliminary evidence suggests that white matter abnormalities may be predictive of poor outcome. A better understanding of the relationship between neurocognitive and neuroimaging assays and functional outcome has the potential to improve current treatment options and provide targets for new treatment strategies in bipolar disorder.

Sustained attention as a potential endophenotype for bipolar disorder

OBJECTIVE

Nowadays, it is accepted that to identify the biological basis of psychiatric illnesses it would be useful to deconstruct them into the most basic manifestations, such as cognitive deficits. The aim of this study was to set attention deficit as a stable vulnerability marker of bipolar disorder.

METHOD

Sustained attention was evaluated by the Continuous Performance Test (DS-CPT) in 143 euthymic bipolar patients and 105 controls. To estimate the influence of clinical profile in attention, patients completed a semi-structured interview.

RESULTS

Bipolar patients showed a deficit in attention during euthymic periods. This disturbance correlated with years of evolution, age of onset and age of first hospitalisation; and was not influenced by other clinical data.

CONCLUSION

Sustained attention may be considered as an endophenotype of the illness.

Interactions between bipolar disorder and antisocial personality disorder in trait impulsivity and severity of illness

OBJECTIVE

We investigated trait impulsivity in bipolar disorder and antisocial personality disorder (ASPD) with respect to severity and course of illness.

METHOD

Subjects included 78 controls, 34 ASPD, 61 bipolar disorder without Axis II disorder, and 24 bipolar disorder with ASPD, by Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (SCID-I and -II). Data were analyzed using general linear model and probit analysis.

RESULTS

Barratt Impulsiveness Scale (BIS-11) scores were higher in ASPD (effect sizes 0.5-0.8) or bipolar disorder (effect size 1.45) than in controls. Subjects with both had more suicide attempts and previous episodes than bipolar disorder alone, and more substance-use disorders and suicide attempts than ASPD alone. BIS-11 scores were not related to severity of crimes.

CONCLUSION

Impulsivity was higher in bipolar disorder with or without ASPD than in ASPD alone, and higher in ASPD than in controls. Adverse effects of bipolar disorder in ASPD, but not of ASPD in bipolar disorder, were accounted for by increased impulsivity.