Meta-analytic review of neurocognition in bipolar II disorder

Cognitive Impairment in Euthymic Pediatric Bipolar Disorder: A Systematic Review and Meta-Analysis

OBJECTIVE

To perform a systematic review and meta-analysis of studies investigating neurocognition in euthymic youths with bipolar disorder (BD) compared to healthy controls (HCs).

METHOD

A systematic literature search was conducted in the PubMed/MEDLINE, PsycINFO, and EMBASE databases from inception up until March 23, 2016, for original peer-reviewed articles that investigated neurocognition in euthymic youths with BD compared to HCs. Effect sizes (ES) for individual tests were extracted. In addition, results were grouped according to cognitive domain. This review complied with the PRISMA statement guidelines.

RESULTS

A total of 24 studies met inclusion criteria (N = 1,146; 510 with BD). Overall, euthymic youths with BD were significantly impaired in verbal learning, verbal memory, working memory, visual learning, and visual memory, with moderate to large ESs (Hedge's g 0.76-0.99); significant impairments were not observed for attention/vigilance, reasoning and problem solving, and/or processing speed. Heterogeneity was moderate to large (I² ≥ 50%) for most ES estimates. Differences in the definition of euthymia across studies explained the heterogeneity in the ES estimate for verbal learning and memory. We also found evidence for other potential sources of heterogeneity in several ES estimates including co-occurring attention-deficit/hyperactivity disorder (ADHD) and anxiety disorders, and the use of medications. In addition, the use of different neuropsychological tests appeared to contribute to heterogeneity of some estimates (e.g., attention/vigilance domain).

CONCLUSION

Euthymic youths with BD exhibit significant cognitive dysfunction encompassing verbal learning and memory, working memory, and/or visual learning and memory domains. These data indicate that for a subset of individuals with BD, neurodevelopmental factors may contribute to cognitive dysfunction.

The difficult lives of individuals with bipolar disorder: A review of functional outcomes and their implications for treatment

BACKGROUND

Most longitudinal or treatment studies in bipolar disorder have used symptomatic or syndromal status as the primary outcome variable. More recently, psychosocial functioning has been highlighted as a key domain of outcome. Patients with bipolar disorder appear to be impaired in all functional domains, although the factors that cause impairment have not been clearly specified.

METHODS

This paper reviews cross-sectional and longitudinal studies on functional impairment and its relationship to symptomatic, neurocognitive, personality, and stress variables in bipolar disorder; and the implications of these relationships for defining treatment targets. 93 articles were located through comprehensive MEDLINE, SCOPUS and Web of Science searches.

RESULTS AND DISCUSSION

Functional recovery following a mood episode consistently lags behind symptomatic and syndromal recovery. Longer term functional impairment is only partly explained by the number of manic/hypomanic episodes. Depression (including subsyndromal states) and persistent neurocognitive impairment are the strongest correlates of functional impairment in bipolar disorder, with personality and psychosocial stressors playing secondary roles. Possible treatment options include: more aggressive treatment of subthreshold depressive states, pharmacotherapies that target cognition (e.g., stimulants), and adjunctive psychotherapies including cognitive remediation.

Neuropsychological profiles of major depressive disorder and bipolar disorder during euthymia. A systematic literature review of comparative studies

Bipolar disorder and major depressive disorder have been shown to be associated with neurocognitive abnormalities during periods of clinical remission. However, at present, there is no consensus on whether these disorders have distinctive cognitive profiles. The aim of this study was to provide an updated systematic review of studies comparing neuropsychological functioning between bipolar disorder and major depressive disorder during remission. Main findings included the following: 1) no differences regarding performances in measures of attention and processing speed, executive functions and theory of mind were found between both patient groups and 2) regarding verbal memory, preliminary evidence points towards a more defective performance in patients with bipolar disorder than those with major depressive disorder. However, several variables with negative impact on cognition (medication status, age at onset, premorbid IQ, bipolar subtype, among others) were not adequately controlled in most studies. In conclusion, evidence from studies exploring neuropsychological profiles in bipolar disorder and major depressive disorder could not provide clues to differentiate these mood disorders. Larger studies with adequate control of confounding variables would be necessary to elucidate if the finding of more defective verbal memory performance in bipolar disorder is truly explained by distinct underlying mechanisms.

Differences in clinical presentation between bipolar I and II disorders in the early stages of bipolar disorder: A naturalistic study

AIM

In a naturalistic clinical study of patients in the early stages of bipolar disorders the aim was to assess differences between patients with bipolar I (BD I) and bipolar II (BD II) disorders on clinical characteristics including affective symptoms, subjective cognitive complaints, functional level, the presence of comorbid personality disorders and coping strategies.

METHODS

Diagnoses were confirmed using the Structured Clinical Interview for DSM-IV Disorders. Clinical symptoms were rated with the Young Mania Rating Scale and the Hamilton Depression Rating Scale, and functional status using the Functional Assessment Short Test. Cognitive complaints were assessed using the Massachusetts General Hospital Cognitive and Physical Functioning Questionnaire, the presence of comorbid personality disorders using the Standardized Assessment of Personality - Abbreviated Scale and coping style using the Coping Inventory for Stressful Situations.

RESULTS

In total, 344 patients were included (BD I (n=163) and BD II (n=181). Patients with BD II presented with significantly more depressive symptoms, more cognitive complaints, lower overall functioning, and a higher prevalence of comorbid personality disorders. Finally, they exhibited a trend towards using less adaptive coping styles.

LIMITATION

It cannot be omitted that some patients may have progressed from BD II to BD I. Most measures were based on patient self report.

CONCLUSIONS

Overall, BD II was associated with a higher disease burden. Clinically, it is important to differentiate BD II from BD I and research wise, there is a need for tailoring and testing specific interventions towards BD II.

Exposure to childhood trauma is associated with altered n-back activation and performance in healthy adults: implications for a commonly used working memory task

Previous research suggests that a history of early life stress (ELS) impacts working memory (WM) in adulthood. Despite the widespread use of WM paradigms, few studies have evaluated whether ELS exposure, in the absence of psychiatric illness, also impacts WM-associated brain activity in ways that might improve sensitivity to these ELS effects or provide insights into the mechanisms of these effects. This study evaluated whether ELS affects WM behavioral performance and task-associated activity by acquiring 3T functional images from 27 medication-free healthy adults (14 with ELS) during an N-back WM task that included 0- and 2-back components. Whole brain voxel-wise analysis was performed to evaluate WM activation, followed by region of interest analyses to evaluate relationships between activation and clinical variables. ELS was associated with poorer accuracy during the 2-back (79% ± 19 vs. 92% ± 9, p = 0.049); accuracy and response time otherwise did not differ between groups. During the 0-back, ELS participants demonstrated increased activation in the superior temporal gyrus/insula, left inferior parietal lobule (IPL) (both corrected p < 0.001), and middle temporal and parahippocampal gyrus (MTG/PHG)(corrected p < 0.010). During the 2-back, ELS was associated with greater activation in the IPL, MTG/PHG and inferior frontal gyrus (corrected p < 0.001), with a trend towards precuneus activation (p = 0.080). These findings support previous research showing that ELS is associated with impaired neurobehavioral performance and changes in brain activation, suggesting recruitment of additional cognitive resources during WM in ELS. Based on these findings, ELS screening in future WM imaging studies appears warranted.

The Relationship Between Neurocognitive Functioning and Occupational Functioning in Bipolar Disorder: A Literature Review

Neurocognitive impairment in Bipolar Disorder (BD) has been widely reported, even during remission. Neurocognitive impairment has been identified as a contributing factor towards unfavourable psychosocial functioning within this population. The objective of this review was to investigate the association between neurocognitive impairment and occupational functioning in BD. A literature review of English-language journal articles from January 1990 to November 2013 was undertaken utilising the PsychINFO, Scopus and Web of Knowledge databases. Studies that made specific reference to occupational outcomes were included, and those that reported on global psychosocial measures were excluded. Majority of the papers reviewed (20 out of 23) identified an association between neurocognitive impairment (particularly in executive functioning, verbal learning and memory, processing speed and attention) and occupational functioning. Several methodological issues were identified. There was a discrepancy in the measures used to assess neurocognitive function across studies and also the definition and measurement of occupational functioning. The clinical features of the samples varied across studies, and confounding variables were intermittently controlled. The review focused on English-language papers only and hence there is a bias toward the Western labour market. These limitations therefore influence the generalizability of the interpreted findings and the reliability of comparisons across studies. Neurocognitive impairment in BD appears to play a role in occupational outcomes. The findings of this review highlight the challenges for future research in this area, particularly in the measurement of neurocognitive and occupational functioning. Incorporating neurocognitive interventions in the treatment of BD, which has traditionally focussed solely on symptomatic recovery, may advance the vocational rehabilitation of these patients.

Are major depression and bipolar disorder neuropsychologically distinct? A meta-analysis of comparative studies

BACKGROUND

Neuropsychological deficits are present in both major depression and bipolar disorder. So far, however, reports directly comparing these mood disorders with regard to cognitive outcomes have been scant and yielded inconsistent results. This work aims to combine the findings of comparative studies of cognition in major depression and bipolar disorder in order to explore whether these neuropsychiatric conditions present with distinct cognitive features.

METHODS

The main online databases were extensively searched to retrieve reports assessing neurocognitive functioning in two groups of mood disorder patients, one with major depressive disorder and another with bipolar disorder, both in the same phase of illness. Between-group effect sizes for cognitive variables were obtained from selected studies and pooled by means of meta-analytic procedures.

RESULTS

During euthymia, a significant overall effect size (Hedges'g=0.64, P<0.001) favoring major depressive disorder was found for verbal memory as assessed with list learning tests, whereas no significant between-group differences were found for the remaining variables analyzed. During depressive episodes, similar cognitive outcomes were observed between groups.

CONCLUSION

At present, it is not possible to postulate specific neuropsychological profiles for major depression and bipolar disorder in light of available evidence. It remains to be ascertained whether the differences found for verbal memory constitute an expression of distinct underlying mechanisms or whether they are best explained by sample characteristics or differential exposure to variables with a negative impact on cognition.

Reconsidering Dietary Polyunsaturated Fatty Acids in Bipolar Disorder: A Translational Picture

Inflammation is an important mediator of pathophysiology in bipolar disorder. The omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acid (PUFA) metabolic pathways participate in several inflammatory processes and have been linked through epidemiologic and clinical studies to bipolar disorder and its response to treatment. We review the proposed role of PUFA metabolism in neuroinflammation, modulation of brain PUFA metabolism by antimanic medications in rodent models, and anti-inflammatory pharmacotherapy in bipolar disorder and in major depressive disorder (MDD). Although the convergence of findings between preclinical and postmortem clinical data is compelling, we investigate why human trials of PUFA as treatment are mixed. We view the biomarker and treatment study findings in light of the evidence for the hypothesis that arachidonic acid hypermetabolism contributes to bipolar disorder pathophysiology and propose that a combined high n-3 plus low n-6 diet should be tested as an adjunct to current medication in future trials.

Effect of alcohol and illicit substance use on verbal memory among individuals with bipolar disorder

BACKGROUND

Cognitive impairment is a well-established feature of bipolar disorder (BD). Comorbid BD and substance use leads to poor psychosocial and clinical outcomes. However, knowledge on the neurocognitive functioning of individuals with dual diagnosis is limited. The aim of this study is to assess the cognitive performance of subjects with BD, BD with comorbid alcohol use disorder (AUD), and BD with comorbid illicit substance use disorders (SUD) as compared to healthy individuals.

METHODS

We included 270 inpatients and outpatients with BD and 211 healthy controls. The diagnostic of BD and substance use disorder was assessed using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders Axis I. Demographic and clinical information were also collected. The cognitive assessment included the Wechsler Test of Adult Reading (WTAR), and a revised version of the California Verbal Learning Test (CVLT) as part of the South Texas Assessment of Neurocognition (STAN).

RESULTS

The STAN was administered to 134 BD patients (100 female, M±SD: 37.37±12.74 years), 72 BD patients with AUD (40 female, M±SD: 38.42±11.82), 64 BD patients with SUD (39 female, M±SD: 34.50±10.57), and 211 healthy controls with no lifetime history of mental illness and substance use (127 female, M±SD: 34.80±12.57 years). In terms of clinical characteristics, BD+SUD showed a marginally earlier onset of illness compared to BD. Compared to HC, BD performed poorly in the immediate recall and short-delay free tests of the CVLT, while BD patients with AUD and SUD showed significant memory deficits in both the immediate recall and recognition components of the CVLT. There were no differences in memory performance between BD and BD with either AUD or SUD.

CONCLUSIONS

A history of substance use disorders is associated with an earlier onset of BD. BD has marked effects on processes underlying the encoding of new information, while comorbid substance use in BD impairs more specifically the recognition of previously presented information. Future longitudinal studies should evaluate the effects of AUD and SUD on illness progression and therapeutic outcomes.

The role of white matter in personality traits and affective processing in bipolar disorder

BACKGROUND

Bipolar disorder (BD) is characterized by affective processing bias and variations in personality traits. It is still unknown whether these features are linked to the same structural brain alterations. The aim of this study was to investigate relationships between specific personality traits, white matter (WM) properties, and affective processing in BD and HC.

METHODS

24 healthy controls (HC) and 38 adults with BDI (HC: 29.47 ± 2.23 years, 15 females; BDI: 32.44 ± 1.84 years, 20 females) completed clinical scales and the Big Five Inventory. They were also administered the Affective Go/No-Go (AGN) and the Rapid Visual Processing (RVP) tasks of the Cambridge Neuropsychological Test Automated Battery. Diffusion Tensor Imaging (DTI) assessed the microstructure of WM tracts.

RESULTS

In BDI measures of WM properties were reduced across all major brain white matter tracts. As expected, individuals with BDI reported greater neuroticism, lower agreeableness and conscientiousness, and made a greater number of errors in response to affective stimuli in the AGN task compared to HC. High neuroticism scores were associated with faster AGN latency, and overall reduced AGN accuracy in both HC and BDI. Elevated FA values were associated with reduced neuroticism and increased cognitive processing in HC but not in BDI.

CONCLUSIONS

Our findings showed important potential links between personality, affective processing and WM integrity in BD. In the future therapeutic interventions for BD using brain stimulation protocols might benefit from the use of DTI to target pathways underlying abnormal affective processing.

Cortical thickness, volume and surface area in patients with bipolar disorder types I and II

BACKGROUND

Bipolar disorder (BD) is a common chronic psychiatric disorder mainly characterized by episodes of mania, hypomania and depression. The disorder is associated with cognitive impairments and structural brain abnormalities, such as lower cortical volumes in primarily frontal brain regions than healthy controls. Although bipolar disorder types I (BDI) and II (BDII) exhibit different symptoms and severity, previous studies have focused on BDI. Furthermore, the most frequently investigated measure in this population is cortical volume. The aim of our study was to investigate abnormalities in patients with BDI and BDII by simultaneously analyzing cortical volume, thickness and surface area, which yields more information about disease- and symptom-related neurobiology.

METHODS

We used MRI to measure cortical volume, thickness and area in patients with BDI and BDII as well as in healthy controls. The large study cohort enabled us to adjust for important confounding factors.

RESULTS

We included 81 patients with BDI, 59 with BDII and 85 controls in our analyses. Cortical volume, thickness and surface area abnormalities were present in frontal, temporal and medial occipital regions in patients with BD. Lithium and antiepileptic drug use had an effect on the observed differences in medial occipital regions. Patients with the subtypes BDI and BDII displayed common cortical abnormalities, such as lower volume, thickness and surface area than healthy controls in frontal brain regions but differed in temporal and medial prefrontal regions, where only those with BDI had abnormally low cortical volume and thickness.

LIMITATIONS

The group differences can be explained by progressive changes, but also by premorbid conditions. They could also have been influenced by unknown factors, such as social, environmental or genetic factors.

CONCLUSION

Our findings suggest diagnosis-related neurobiological differences between the BD subtypes, which could explain distinct symptoms and point to potential biomarkers that could inform the subtype diagnosis of BD.

Cognitive variability in bipolar II disorder: who is cognitively impaired and who is preserved

OBJECTIVES

Although it is well established that euthymic patients with bipolar disorder can have cognitive impairment, substantial heterogeneity exists and little is known about the extent and severity of impairment within the bipolar II disorder subtype. Therefore, the main aim of this study was to analyze cognitive variability in a sample of patients with bipolar II disorder.

METHODS

The neuropsychological performance of 116 subjects, including 64 euthymic patients with bipolar II disorder and 52 healthy control subjects, was examined and compared by means of a comprehensive neurocognitive battery. Neurocognitive data were analyzed using a cluster analysis to examine whether there were specific groups based on neurocognitive patterns. Subsequently, subjects from each cluster were compared on demographic, clinical, and functional variables.

RESULTS

A three-cluster solution was identified with an intact neurocognitive group (n = 29, 48.3%), an intermediate or selectively impaired group (n = 24, 40.0%), and a globally impaired group (n = 7, 11.6%). Among the three clusters, statistically significant differences were observed in premorbid intelligence quotient (p = 0.002), global functional outcome (p = 0.021), and leisure activities (p = 0.001), with patients in the globally impaired cluster showing the lowest attainments. No differences in other clinical characteristics were found among the groups.

CONCLUSIONS

These results confirm that neurocognitive variability is also present among patients with bipolar II disorder. Approximately one-half of the patients with bipolar II disorder were cognitively impaired, and among them 12% were severely and globally impaired. The identification of different cognitive profiles may help to develop cognitive remediation programs specifically tailored for each cognitive profile.

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.

The differences in temperament-character traits, suicide attempts, impulsivity, and functionality levels of patients with bipolar disorder I and II

BACKGROUND

The primary aim of this study was to compare the differences in temperament-character traits, suicide attempts, impulsivity, and functionality levels of patients with bipolar disorder I (BD-I) and bipolar disorder II (BD-II).

METHODS

Fifty-two BD-I patients and 49 BD-II patients admitted to Erenköy Mental and Neurological Disease Training and Research Hospital psychiatry clinic and fifty age- and sex-matched healthy control subjects were enrolled in this study. A structured clinical interview for Diagnostic and Statistical Manual of Mental Disorders, 4th Edition Axis I Disorders, Temperament and Character Inventory, Barrett Impulsiveness Scale-11 (BIS-11), Hamilton Depression Inventory Scale, Young Mania Rating Scale, and Bipolar Disorder Functioning Questionnaire (BDFQ) were administered to patients and to control group.

RESULTS

No statistically significant difference in sociodemographic features existed between the patient and control groups (P>0.05). Thirty-eight subjects (37.62%) in the patient group had a suicide attempt. Twenty-three of these subjects (60.52%) had BD-I, and 15 of these subjects (39.47%) had BD-II. Suicide attempt rates in BD-I and II patients were 60.52% and 39.47%, respectively (P<0.05). Comparison of BD-I and II patients with healthy control subjects revealed that cooperativeness (C), self-directedness (Sdi), and self-transcendence (ST) scores were lower and novelty seeking (NS1 and NS2), harm avoidance (HA4), and reward dependence (RD2) subscale scores were higher in patients with BD-I. When BD-I patients were compared with BD-II patients, BIS-11 (attention) scores were higher in patients with BD-II and BIS-11 (motor and nonplanning impulsivity) scores were higher in patients with BD-I. According to BDFQ, relations with friends, participation in social activities, daily activities and hobbies, and occupation subscale scores were lower and taking initiative subscale scores were higher in patients with BD-I. Social withdrawal subscale scores were higher in patients with BD-II.

CONCLUSION

In our study, NS, HA, and RD scores that may be found high in suicide attempters and Sdi scores that may be found low in suicide attempters were as follows: NS1, NS2, HA4, and RD2 subscale scores were high and Sdi scores were low in patients with BD-I, suggesting a higher rate of suicide attempts in this group of patients. In addition, C and Sdi scores that indicate a predisposition to personality disorder were significantly lower in patients with BD-I than patients with BD-II and healthy controls, suggesting a higher rate of personality disorder comorbidity in patients with BD-I. Higher impulsivity and suicidality rates and poorer functionality in patients with BD-I also suggest that patients with BD-I may be more impulsive and more prone to suicide and have poorer functionality in some areas.

White matter microstructural characteristics in Bipolar I and Bipolar II Disorder: A diffusion tensor imaging study

BACKGROUND

Diffusion tensor imaging (DTI) studies of bipolar disorder (BD) report contrasting results and are mainly focused on bipolar I (BD-I) samples. We aimed at investigating how and where DTI parameters differ between BD-I and bipolar II (BD-II) and between BD and healthy control subjects (HC).

METHODS

We conducted a tract-based spatial statistics analysis of DTI derived parameters, namely fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) in a matched sample of 50 BD (25 BD-I and 25 BD-II) during the chronic course of the illness and 50 HC.

RESULTS

Compared to BD-I and HC, BD-II showed lower FA but no significant AD or RD differences in the right inferior longitudinal fasciculus (ILF). Both patient groups showed lower AD and RD in the left internal capsule and lower AD across the left ILF, the cortico-spinal tract within the right hemisphere and bilaterally in the cerebellum with respect to HC.

LIMITATIONS

Patients were medicated at the time of scanning; the BD-II group had higher Hamilton Rating Scale for Depression scores than the BD-I group.

CONCLUSIONS

BD-II patients differ from BD-I in the ILF. Both BD subtypes showed widespread white matter (WM) changes in the internal capsule, cortico-spinal tract and cerebellum. The loss of WM integrity in BD-II might be due to demyelination whereas WM changes common to both subgroups could be attributable to axonal damage.

Cognitive function in euthymic bipolar disorder (BP I) patients with a history of psychotic symptoms vs. schizophrenia

Patients with bipolar disorder show cognitive deficits including executive function, which appear to be related to social functioning and outcome. However, subgroups within the spectrum as well as psychopathological features, current mood state/euthymia and disease stage might be confounding factors. We analysed data tests from the Wechsler Intelligence Scale (WIE), verbal fluency (COWA) and trail making tests (TMT-A and TMT-B) obtained in a selected subgroup of currently bipolar I disorder patients, who were currently euthymic and had a history of psychotic symptoms, and compared them to patients with schizophrenia (in remission) and healthy controls, all matched for age, gender, and handedness. Schizophrenia patients showed more severe cognitive impairment, including digit symbol and arithmetic tests, as well as TMT-B (compared to healthy controls), but bipolar patients had stronger impairment on the letter number sequencing test, an indicator of working memory and processing speed. There were no group effects on most verbal fluency tasks (except impairment of schizophrenia patients on one subscale of category fluency). Within the limitations of the study design, our results suggest that even in subgroups of presumably more severely impaired bipolar patients, some cognitive dimensions might achieve remission, possibly related to considerable state effects at testing.

Meta-analysis of Cognitive Impairment in First-Episode Bipolar Disorder: Comparison With First-Episode Schizophrenia and Healthy Controls

Neurocognitive deficits are evident both in established schizophrenia and bipolar disorder (BP). However, it has been suggested that schizophrenia, but not BP, is characterized by neurodevelopmental abnormalities that can lead to cognitive deficits at the earliest stages of the illness. The aim of this meta-analytic review was to compare neurocognitive deficits in first-episode BP (FEBP) with healthy controls and first-episode schizophrenia (FES) patients. The current meta-analysis included a total of 22 adult studies and involved comparisons of 533 FEBP patients with 1417 healthy controls and 605 FEBP and 822 FES patients. FEBP patients were significantly impaired in all cognitive domains (d = 0.26-0.80) and individual tasks (d = 0.22-0.66) investigated. FES patients significantly underperformed FEBP patients in most cognitive domains (d = 0.05-0.63) and on individual tasks (d = 0.13-0.77). Neuropsychological impairment, which is comparable to chronic BP, was evident in FEBP. Similar to chronic patients, cognitive functions in FEBP lie intermediate between FES and healthy controls. Neurodevelopmental factors are likely to play a significant role not only in schizophrenia but also in BP.

Verbal learning impairment in euthymic bipolar disorder: BDI v BDII

OBJECTIVES

Cognitive impairment is known to occur in bipolar disorder (BD), even in euthymic patients, with largest effect sizes often seen in Verbal Learning and Memory Tasks (VLT). However, comparisons between BD Type-I and Type-II have produced inconsistent results partly due to low sample sizes.

METHODS

This study compared the performance of 183 BDI with 96 BDII out-patients on an adapted version of the Rey Verbal Learning Task. Gender, age, years of education, mood scores and age at onset were all used as covariates. Current medication and a variety of illness variables were also investigated for potential effects on VLT performance.

RESULTS

BDI patients were significantly impaired relative to BDII patients on all five VLT outcome measures after controlling for the other variables [Effect Sizes=.13-.17]. The impairments seem to be unrelated to drug treatment and largely unrelated to illness variables, although age of onset affected performance on three outcome measures and number of episodes of mood elevation affected performance on one.

LIMITATIONS

This study used historical healthy controls. Analysis of potential drug effects was limited by insufficient participants not being drug free. Cross-sectional nature of the study limited the analysis of the potential effect of illness variables.

CONCLUSIONS

This study replicates earlier findings of increased verbal learning impairment in BDI patients relative to BDII in a substantially larger sample. Such performance cannot be wholly explained by medication effects or illness variables. Thus, the cognitive impairment is likely to reflect a phenotypic difference between bipolar sub-types.

Toward the identification of neurocognitive subtypes in euthymic patients with bipolar disorder

BACKGROUND

Cross-sectional and meta-analytic studies showed that patients with bipolar disorder (BD) had neurocognitive impairments even during periods of euthymia. The aim of this study was to estimate the prevalence of BD patients with and without clinically significant cognitive impairments, as well as to analyze clinical and functional variables in these subgroups.

METHODS

Hundred patients with BD and 40 healthy controls were assessed with an extensive neurocognitive assessment. Soft (some cognitive domain with a performance below 1.5 SD of the mean) and hard (at least two domains with values below 2 SD of the mean) criteria were utilized to define clinically significant cognitive impairments.

RESULTS

Using both soft and hard criteria, the prevalence of clinically significant cognitive impairments was higher in people with BD than in healthy controls. 70% of patients only showed failures of small effect (d=0.21-0.35) in 2 measures of executive functions. Moreover, 30% of patients were indistinguishable from healthy subjects in terms of both neurocognitive and psychosocial functioning. On the contrary, 30% of the sample showed more severe cognitive deficits than those usually reported in literature and had the worst psychosocial functioning.

CONCLUSIONS

The fact that cognitive impairments are very heterogeneous among euthymic patients with BD could contribute to understanding differences in functional outcome. Theoretical and practical implications of these findings are discussed.

Measuring cognitive function in MDD: emerging assessment tools

Cognitive impairment is emerging as an important therapeutic target in patients with psychiatric illnesses, including major depressive disorder (MDD). The objective of this general overview is to briefly review the evidence for cognitive impairment in MDD and to summarize a representative sample of cognitive assessment tools currently available to assess cognitive function in depressed patients. Study results in MDD patients with cognitive dysfunction are somewhat inconsistent, likely due to the heterogeneity of the disorder as well as the use of diverse assessment tools. Measuring cognitive changes in this population is challenging. Cognitive symptoms are typically less severe than in patients with schizophrenia and bipolar disorder, requiring greater sensitivity than afforded by existing tools. Preliminary evidence suggests antidepressant treatments may improve cognitive functioning as a direct result of ameliorating depressive symptoms; however, any procognitive effects have not been elucidated. To evaluate antidepressant efficacy in MDD patients with cognitive dysfunction, a standardized cognitive battery for use in clinical trials is essential.

Neurocognitive functioning in the premorbid stage and in the first episode of bipolar disorder: a systematic review

It is well known that patients with bipolar disorder (BD) have cognitive impairments even during periods of euthymia. However, to date it remains unclear the moment when these deficits onset. Therefore, the aim of this study was to review the evidence focusing on the cognitive status of patients with BD in their premorbid stage and in their first episode. An extensive search was conducted through the online databases Pubmed/PsychInfo, covering the period between 1980 and 2014. A total of 23 studies were selected for the review (nine studies explored premorbid stage of people who lately develop BD and 14 examined first-episodes in bipolar patients). There is evidence that general intelligence is not impaired in the premorbid stage. Impairments in verbal memory, attention, and executive functions tend to be present during and after the first episode. Preliminary evidence suggests that these deficits in specific cognitive domains might precede the onset of illness.

Advancing understanding of executive function impairments and psychopathology: bridging the gap between clinical and cognitive approaches

Executive function (EF) is essential for successfully navigating nearly all of our daily activities. Of critical importance for clinical psychological science, EF impairments are associated with most forms of psychopathology. However, despite the proliferation of research on EF in clinical populations, with notable exceptions clinical and cognitive approaches to EF have remained largely independent, leading to failures to apply theoretical and methodological advances in one field to the other field and hindering progress. First, we review the current state of knowledge of EF impairments associated with psychopathology and limitations to the previous research in light of recent advances in understanding and measuring EF. Next, we offer concrete suggestions for improving EF assessment. Last, we suggest future directions, including integrating modern models of EF with state of the art, hierarchical models of dimensional psychopathology as well as translational implications of EF-informed research on clinical science.

Assessing cognitive function in bipolar disorder: challenges and recommendations for clinical trial design

OBJECTIVE

Neurocognitive impairment in schizophrenia has been recognized for more than a century. In contrast, only recently have significant neurocognitive deficits been recognized in bipolar disorder. Converging data suggest the importance of cognitive problems in relation to quality of life in bipolar disorder, highlighting the need for treatment and prevention efforts targeting cognition in bipolar patients. Future treatment trials targeting cognitive deficits will be met with methodological challenges due to the inherent complexity and heterogeneity of the disorder, including significant diagnostic comorbidities, the episodic nature of the illness, frequent use of polypharmacy, cognitive heterogeneity, and a lack of consensus regarding measurement of cognition and outcome in bipolar patients. Guidelines for use in designing future trials are needed.

PARTICIPANTS

The members of the consensus panel (each of the bylined authors) were selected based upon their expertise in bipolar disorder. Dr Burdick is a neuropsychologist who has studied cognition in this illness for 15 years; Drs Ketter, Calabrese, and Goldberg each bring considerable expertise in the treatment of bipolar disorder, both within and outside of controlled clinical trials. This consensus statement was derived from work together at scientific meetings (eg, symposium presentation at the 2014 Annual Meeting of the American Society of Clinical Psychopharmacology, among others) and ongoing discussions by conference call. With the exception of the public presentations on this topic, these meetings were closed to outside participants.

EVIDENCE

A literature review was undertaken by the authors to identify illness-specific challenges relevant to the design and conduct of treatment trials targeting neurocognition in bipolar disorder. Expert opinion from each of the authors guided the consensus recommendations.

CONSENSUS PROCESS

Consensus recommendations, reached by unanimous opinion of the authors, are provided here as a preliminary guide for future trial design. Recommendations comprise exclusion of certain syndromal-level comorbid diagnoses and current affective instability, restrictions on numbers and types of medications, and use of prescreening assessment to ensure enrollment of subjects with adequate objective evidence of baseline cognitive impairment.

CONCLUSIONS

Clinical trials to address cognitive deficits in bipolar disorder face distinctive design challenges. As such trials move from proof-of-concept to confirmation of clinical efficacy, it will be important to incorporate distinctive design modifications to adequately address these challenges and increase the likelihood of demonstrating cognitive remediation effects. The field is now primed to address these challenges, and a comprehensive effort to formalize best practice guidelines will be a critically important next step.

Functional remediation for patients with bipolar II disorder: improvement of functioning and subsyndromal symptoms

Recently, Functional Remediation (FR) has proven to be effective in improving the functional outcome of euthymic bipolar patients. The aim of this study was to test the efficacy of the FR program in a subsample of euthymic bipolar II patients (BPII). A post-hoc analyses were undertaken using data of 53 BPII outpatients who had participated in a multicenter, rater-blind, randomized, controlled trial exploring the efficacy of FR (n=17) as compared with a Psychoeducation group (PSY) (n=19) and a treatment as usual control group (TAU n=17). The primary outcome variable was the functional improvement defined as the mean change in the Functioning Assessment Short Test (FAST) from baseline to endpoint after the intervention. Regarding the treatment effect, data reveal a significant functional improvement from baseline to endpoint, suggestive for an interaction between program pertinence and time (pre-post). Nevertheless, Tukey׳s post-hoc test only revealed a trend in favor of a better outcome for FR when compared to the other two groups. We also found an interaction between program pertinence and time when analysing the subdepressive symptoms, with BPII patients in FR showing a significant reduction when compared to the PSY group. Our results suggest that the FR appears to be effective in improving the overall functional outcome in BPII, as well as in reducing subdepressive symptoms.

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.

Cognitive dysfunction in bipolar disorder and schizophrenia: a systematic review of meta-analyses

Cognitive impairment is a core feature of schizophrenia (SZ) and bipolar disorder (BD). A neurocognitive profile characterized by widespread cognitive deficits across multiple domains in the context of substantial intellectual impairment, which appears to antedate illness onset, is a replicated finding in SZ. There is no specific neuropsychological signature that can facilitate the diagnostic differentiation of SZ and BD, notwithstanding, neuropsychological deficits appear more severe in SZ. The literature in this field has provided contradictory results due to methodological differences across studies. Meta-analytic techniques may offer an opportunity to synthesize findings and to control for potential sources of heterogeneity. Here, we performed a systematic review of meta-analyses of neuropsychological findings in SZ and BD. While there is no conclusive evidence for progressive cognitive deterioration in either SZ or BD, some findings point to more severe cognitive deficits in patients with early illness onset across both disorders. A compromised pattern of cognitive functioning in individuals at familiar and/or clinical risk to psychosis as well as in first-degree relatives of BD patients suggests that early neurodevelopmental factors may play a role in the emergence of cognitive deficits in both disorders. Premorbid intellectual impairment in SZ and at least in a subgroup of patients with BD may be related to a shared genetically determined influence on neurodevelopment.

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.

Outcome of cognitive performances in bipolar euthymic patients after a depressive episode: a longitudinal naturalistic study

BACKGROUND

Cognitive functions have been investigated across depressed, manic, hypomanic, mixed and euthymic episodes of bipolar disorder, but the stability or the progression of cognitive impairment is still under research.

OBJECTIVE

The purpose of the present study was to assess the outcome of cognitive functions in bipolar patients following a depressive episode, after a 6-month period in the absence of mood symptoms.

METHOD

63 bipolar patients were tested with a battery of neurocognitive tests both at baseline (during an acute depressive episode) and after 6 months of euthymia. The cognitive domains assessed included memory, attention, verbal fluency, processing speed and executive functions. Cognitive performances were compared with those of a control group (40 healthy control subjects), both in depression and in euthymia.

RESULTS

Patients scored worse than control subjects in several cognitive domains, both in depression and euthymia. The most impaired cognitive functions were executive functions and verbal memory. Between the two moments of assessment bipolar patients obtained a significant improvement in memory, verbal fluency, attention and information processing speed. Psychomotor speed showed no difference between depression and euthymia.

CONCLUSIONS

Bipolar patients showed impairment in several cognitive domains during depression. A certain degree of impairment remained even after the remission of the affective episode in relationship with the executive functions. Between depression and euthymia, bipolar patients showed important cognitive improvements.

Evaluation of cognitive function in bipolar disorder using the Brief Assessment of Cognition in Affective Disorders (BAC-A)

BACKGROUND

Although cognitive impairment is a core feature of bipolar disorder (BD) there is no instrument of choice for the assessment of bipolar patients. The aim of this study is to assess cognitive performance using the Brief Assessment of Cognition in Affective Disorders (BAC-A), a comprehensive test battery developed specifically for BD, and determine its suitability to estimate global functioning.

METHODS

The BAC-A was administered to 93 BD patients (M ± S.E: 35.18 ± 1.39 years) and 56 healthy controls (HC - M ± S.E: 36.17 ± 1.91 years). The scores of the BAC-A were combined in eight summary scores: visuomotor, immediate affective and non-affective memory, verbal fluency, delayed affective and non-affective memory, inhibition, and problem solving. Post hoc analyses were performed on subtests of the summary scores found to be significantly different between BD patients and HC. Correlational analyses explored the association between the Global Assessment of Functioning (GAF) score and cognitive functioning.

RESULTS

Compared to HC, BD patients showed a significant impairment in short-term non-affective memory and verbal fluency. Poorer performance in verbal memory and verbal fluency summary scores correlated positively with reduced GAF.

CONCLUSIONS

Our results are consistent with previous reports of verbal memory and verbal fluency impairment in BD. The deficits in short-term memory and semantic fluency may indicate inefficient learning strategies and/or difficulties in retrieving information. The BAC-A could be used to estimate global functioning in BD patients.

Effects of mood state on divided attention in patients with bipolar disorder: evidence for beneficial effects of subclinical manic symptoms

A relatively small number of studies have been dedicated to the differential effects of the current mood state on cognition in patients with a bipolar disorder (BD). The aim of the current study was to investigate the effect of current mood state on divided attention (DA) performance, and specifically examine possible beneficial effects of the (hypo-) manic state. Over a maximum period of 24 months, medication use, divided attention test (a subtest of the Test for Attentional Performance (TAP)) was assessed every 6 months in 189 outpatients with BD. Data were analyzed with multilevel regression analysis (i.e. linear mixed models). DA performance varied considerable over time within patients. Corrected for psychotropic medication a significant quadratic relationship between manic symptoms and DA performance was found, with mild hypomanic symptoms having a positive influence on divided attention scores and moderate to severe manic symptoms having a negative influence. No association between depressive symptoms and DA performance was found. In future research on mania and cognition as well as in the clinical practice both the beneficial and negative effects of mania should be taken into account.

Pathways between neurocognition, social cognition and emotion regulation in bipolar disorder

OBJECTIVE

Converging evidence suggests that in bipolar disorder (BD), social cognition and emotion regulation are affected by the capacity for effective neurocognitive function. Adaptive emotion regulation may also rely on intact social cognition, and it is possible that social cognition acts as a mediator in its relationship with neurocognition. We aimed to address this hypothesis by explicitly examining interrelationships among neurocognition, social cognition and emotion regulation in an out-patient sample meeting criteria for a DSM-IV-TR diagnosis of BD compared with controls.

METHOD

Fifty-one BD patients and 52 healthy controls completed a battery of tests assessing neurocognition, social cognition (emotion perception and theory of mind) and emotion regulation.

RESULTS

Path analysis revealed that in BD, neurocognition was associated with social cognition, but social cognition was not associated with emotion regulation as expected. In contrast, a component of social cognition was found to mediate the relationship between neurocognition and emotion regulation in healthy controls.

CONCLUSION

These findings highlight differences in the pattern of associations between neurocognition, social cognition and emotion regulation across BD patients and controls. In the present data, these results appear to indicate that neurocognitive and social cognitive abilities generally operate in isolation from emotion regulation in BD.

A meta-analysis of neuropsychological functioning in first-episode bipolar disorders

Broad neuropsychological deficits have been consistently demonstrated in well-established bipolar disorder. The aim of the current study was to systematically review neuropsychological studies in first-episode bipolar disorders to determine the breadth, extent and predictors of cognitive dysfunction at this early stage of illness through meta-analytic procedures. Electronic databases were searched for studies published between January 1980 and December 2013. Twelve studies met eligibility criteria (N = 341, mean age = 28.2 years), and pooled effect sizes (ES) were calculated across eight cognitive domains. Moderator analyses were conducted to identify predictors of between-study heterogeneity. Controlling for known confounds, medium to large deficits (ES ≥ 0.5) in psychomotor speed, attention and working memory, and cognitive flexibility were identified, whereas smaller deficits (ES 0.20-0.49) were found in the domains of verbal learning and memory, attentional switching, and verbal fluency. A medium to large deficit in response inhibition was only detected in non-euthymic cases. Visual learning and memory functioning was not significantly worse in cases compared with controls. Overall, first-episode bipolar disorders are associated with widespread cognitive dysfunction. Since euthymia was not associated with superior cognitive performance in most domains, these results indicate that even in the earliest stages of disease, cognitive deficits are not mood-state dependent. The current findings have important implications for whether cognitive impairments represent neurodevelopmental or neurodegenerative processes. Future studies need to more clearly characterise the presence of psychotic features, and the nature and number of previous mood episodes.

Biomarkers and clinical staging in psychiatry

Personalized medicine is rapidly becoming a reality in today's physical medicine. However, as yet this is largely an aspirational goal in psychiatry, despite significant advances in our understanding of the biochemical, genetic and neurobiological processes underlying major mental disorders. Preventive medicine relies on the availability of predictive tools; in psychiatry we still largely lack these. Furthermore, our current diagnostic systems, with their focus on well-established, largely chronic illness, do not support a pre-emptive, let alone a preventive, approach, since it is during the early stages of a disorder that interventions have the potential to offer the greatest benefit. Here, we present a clinical staging model for severe mental disorders and discuss examples of biological markers that have already undergone some systematic evaluation and that could be integrated into such a framework. The advantage of this model is that it explicitly considers the evolution of psychopathology during the development of a mental illness and emphasizes that progression of illness is by no means inevitable, but can be altered by providing appropriate interventions that target individual modifiable risk and protective factors. The specific goals of therapeutic intervention are therefore broadened to include the prevention of illness onset or progression, and to minimize the risk of harm associated with more complex treatment regimens. The staging model also facilitates the integration of new data on the biological, social and environmental factors that influence mental illness into our clinical and diagnostic infrastructure, which will provide a major step forward in the development of a truly pre-emptive psychiatry.

An empirical evaluation of the MATRICS Consensus Cognitive Battery in bipolar disorder

OBJECTIVES

There is a large body of evidence to indicate that neurocognitive impairments in bipolar disorder (BD) may represent viable endophenotypes; however, a standard consensus-based battery of cognitive tests used to measure them is yet to appear. There is potential for a neurocognitive battery which was developed for use in the related disorder, schizophrenia - the MATRICS Consensus Cognitive Battery (MCCB) - to provide a consistent measurement tool with a standard to which the cognitive capacity of BD can be compared to other disorders. However, its suitability for capturing neurocognitive impairment in BD cohorts is not well established. Moreover, neurocognitive tests recently recommended by the International Society for Bipolar Disorders (ISBD) for inclusion in a consensus neurocognitive battery for BD have not been evaluated in the context of the MCCB. An evaluation of (i) the clinical efficacy of the MCCB and (ii) the tests recommended by the ISBD in a BD cohort were the aims of the current study.

METHODS

A total of 50 patients with BD (mean age = 38 years) and 52 healthy controls (mean age = 34 years) completed all of the MCCB subtests, in addition to the well-recognized Trail Making Test-Part B and the Colour-Word Stroop.

RESULTS

Multivariate analyses of variance of the MCCB domains revealed a significant group effect for overall cognition, and significantly reduced patient performance on speed of processing, working memory, and visual and verbal learning. A second multivariate analysis of variance using a newly created composite score called executive function, comprising scores on an existing MCCB subtest in addition to TMT-B and Colour-Word Stroop, revealed significant differences on this domain as well. Subgroup analysis indicated that there were no differences in any domain score performance between symptomatic and euthymic patients, or bipolar I and II disorder patient groups.

CONCLUSIONS

Our findings suggest that the MCCB and two additionally recommended ISBD executive function measures form a promising consensus-based research tool for examining neurocognition in BD.

Using the Brief Assessment of Cognition in Schizophrenia (BACS) to assess cognitive impairment in older patients with schizophrenia and bipolar disorder

OBJECTIVES

A growing body of evidence suggests that impairment in cognitive functioning is an important clinical feature of both schizophrenia and bipolar disorder, and that these cognitive alterations worsen with age. Although cognitive assessments are increasingly becoming a part of research and clinical practice in schizophrenia, a standardized and easily administered test battery for elderly patients with bipolar disorder is still lacking. The Brief Assessment of Cognition in Schizophrenia (BACS) captures those domains of cognition that are the most severely affected in patients with schizophrenia and the most strongly correlated with functional outcome. The primary aim of our study was to investigate the clinical usefulness of the BACS in assessing cognitive functioning in elderly euthymic patients with bipolar disorder, and to compare their cognitive profile to that of elderly patients with schizophrenia.

METHODS

Elderly euthymic patients with bipolar disorder or schizophrenia were assessed using the BACS and a standard cognitive test battery.

RESULTS

Fifty-seven elderly patients (aged 60 years and older) with bipolar disorder (n = 42) or schizophrenia (n = 15) were invited to participate. All of the patients were assessed by the BACS as being cognitively impaired. The patients with bipolar disorder scored significantly higher on the global scale and the verbal memory and attention sub-scores of the BACS than the patients with schizophrenia.

DISCUSSION

The BACS appears to be a feasible and informative cognitive assessment tool for elderly patients with bipolar disorder. We believe that these preliminary results merit further investigation.

Cognitive effects of the ANK3 risk variants in patients with bipolar disorder and healthy individuals

BACKGROUND

Genetic variants within the ankyrin 3 gene (ANK3) have been identified as a risk factor for bipolar disorder. ANK3 influences action potential generation by clustering sodium gated channels and plays an integral role in neurotransmission. Thus, this gene may influence cognition, a process compromised in bipolar disorder. We investigated whether genetic variants of ANK3 would be associated with an array of cognitive functions in patients with bipolar disorder and healthy individuals.

METHODS

In a sample of 49 patients with bipolar disorder and 633 healthy subjects, we examined possible effects of 2 risk variants within ANK3, rs10994336 and rs10761482, on 7 neurocognitive domains.

RESULTS

Compared to healthy subjects, patients with bipolar disorder demonstrated significantly poorer performance on most of the cognitive domains examined. The risk C-allele of rs10761482 was significantly associated with worse performance on verbal comprehension, logical memory and processing speed in patients. This allele was significantly associated with worse performance on executive function and visual memory in healthy individuals. No significant association was observed between rs10994336 and cognition either in patients or healthy individuals.

LIMITATIONS

The sample size of patients with bipolar disorder was small, and most of the patients were on psychotropic medication.

CONCLUSIONS

These results indicate that a risk variant within ANK3 may have an impact on neurocognitive function, suggesting a mechanism by which ANK3 confers risk for bipolar disorder.

Neuropathological and neuromorphometric abnormalities in bipolar disorder: view from the medial prefrontal cortical network

The question of whether BD is primarily a developmental disorder or a progressive, neurodegenerative disorder remains unresolved. Here, we review the morphometric postmortem and neuroimaging literature relevant to the neuropathology of bipolar disorder (BD). We focus on the medial prefrontal cortex (mPFC) network, a key system in the regulation of emotional, behavioral, endocrine, and innate immunological responses to stress. We draw four main conclusions: the mPFC is characterized by (1) a decrease in volume, (2) reductions in neuronal size, and/or changes in neuronal density, (3) reductions in glial cell density, and (4) changes in gene expression. These data suggest the presence of dendritic atrophy of neurons and the loss of oligodendroglial cells in BD, although some data additionally suggest a reduction in the cell counts of specific subpopulations of GABAergic interneurons. Based on the weight of the postmortem and neuroimaging literature discussed herein, we favor a complex hypothesis that BD primarily constitutes a developmental disorder, but that additional, progressive, histopathological processes also are associated with recurrent or chronic illness. Conceivably BD may be best conceptualized as a progressive neurodevelopmental disorder.

Psychotherapy for Bipolar Disorder in Adults: A Review of the Evidence

Although pharmacotherapy is the mainstay of treatment for bipolar disorder, medication offers only partial relief for patients. Treatment with pharmacologic interventions alone is associated with disappointingly low rates of remission, high rates of recurrence, residual symptoms, and psychosocial impairment. Bipolar-specific therapy is increasingly recommended as an essential component of illness management. This review summarizes the available data on psychotherapy for adults with bipolar disorder. We conducted a search of the literature for outcome studies published between 1995 and 2013 and identified 35 reports of 28 randomized controlled trials testing individual or group psychosocial interventions for adults with bipolar disorder. These reports include systematic trials investigating the efficacy and effectiveness of individual psychoeducation, group psychoeducation, individual cognitive-behavioral therapy, group cognitive-behavioral therapy, family therapy, interpersonal and social rhythm therapy, and integrated care management. The evidence demonstrates that bipolar disorder-specific psychotherapies, when added to medication for the treatment of bipolar disorder, consistently show advantages over medication alone on measures of symptom burden and risk of relapse. Whether delivered in a group or individual format, those who receive bipolar disorder-specific psychotherapy fare better than those who do not. Psychotherapeutic strategies common to most bipolar disorder-specific interventions are identified.

Social cognition throughout the three phases of bipolar disorder: a state-of-the-art overview

Although it is now well documented that bipolar disorder (BD) often presents with cognitive deficits and suboptimal social adjustment, the social cognitive profile of the illness throughout its three phases remains unclear. An extensive search was conducted through the online databases EBSCO, PsychInfo, PubMed, ScienceDirect, and Wiley-Blackwell, covering the period between 1990 and 2012. Fifty-one studies comparing the social cognitive performance of bipolar patients with that of healthy controls were identified. Deficits in emotion recognition and theory of mind were found in manic, depressed, and euthymic bipolar subjects. Furthermore, altered face emotion recognition and brain-related abnormalities were noted both in euthymic patients and subjects at risk for BD. The influence of clinical and neurocognitive variables on the social cognitive performance of bipolar patients remains to be ascertained. Future directions for research are discussed.

A longitudinal study of cognition in asymptomatic and mildly symptomatic bipolar disorder patients

Bipolar disorder (BD) is characterized by cognitive deficits that impair patients' functioning and quality of life. Most of the earlier studies assessing changes in BD patients' cognitive functioning over time utilized a cross-sectional research design. The few longitudinal studies that were conducted tended to have methodological limitations such as very short follow-up periods, recruitment of acutely ill patients, and lack of assessment of practice effects. The current study aimed to assess changes over time in the cognitive functioning of typical BD outpatients. For this purpose, asymptomatic and mildly symptomatic BD outpatients were assessed at baseline and after two years (n=31). At baseline, the cognitive functioning of the BD patients was compared to that of gender- and age-matched healthy controls. Practice effects were estimated by re-assessing the controls one week after their first assessment. Compared to the controls, BD patients had deficits in psychomotor speed, sustained attention, and one domain of executive functioning (cognitive planning). No evidence was found of a decline in their cognitive functioning over the two year time interval. These findings support a developmental model of cognitive impairment in BD. Studies using longer follow-up periods and larger sample sizes, however, are needed before these conclusions can be stated confidently.

Neuropsychology, social cognition and global functioning among bipolar, schizophrenic patients and healthy controls: preliminary data

This study aimed to determine the extent of impairment in social and non-social cognitive domains in an ecological context comparing bipolar (BD), schizophrenic (SKZ) patients and healthy controls (HC). The sample was enrolled at the Department of Psychiatry of Policlinico Hospital, University of Milan; it includes stabilized SKZ patients (n = 30), euthymic bipolar patients (n = 18) and HC (n = 18). Patients and controls completed psychiatric assessment rating scales, the Brief Assessment of Cognition in Schizophrenia (BACS) and the Executive and Social Cognition Battery (ESCB) that contains both ecological tests of executive function and social cognition, in order to better detect cognitive deficits in patients with normal results in standard executive batteries. The three groups differed significantly for gender and substance abuse, however, the differences did not influence the results. BD patients showed less impairment on cognitive performance compared to SKZ patients, even in “ecological” tests that mimic real life scenarios. In particular, BD performed better than SKZ in verbal memory (p < 0.0038) and BACS symbol coding (p < 0.0043). Regarding the ESCB tests, in the Hotel task SKZ patients completed significantly less tasks (p < 0.001), showed a greater number of errors in Multiple Errands Test (MET-HV) (p < 0.0248) and a worse performance in Theory of Mind (ToM) tests (p < 0.001 for the Eyes test and Faux pas test). Both patients' groups performed significantly worse than HC. Finally, significant differences were found between the two groups in GAF scores, being greater among BD subjects (p < 0.001). GAF was correlated with BACS and ESCB scores showing the crucial role of cognitive and ecological performances in patients' global functioning.

Structural brain alterations in bipolar disorder II: a combined voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) study

BACKGROUND

Brain structural changes have been described in bipolar disorder (BP), but usually studies focused on both I and II subtypes indiscriminately and investigated changes in either brain volume or white matter (WM) integrity. We used combined voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) analysis to track changes in the grey matter (GM) and WM in the brains of patients affected by BPII, as compared to healthy controls.

METHODS

Using VBM and DTI, we scanned 20 DSM-IV-TR BPII patients in their euthymic phase and 21 healthy, age- and gender-matched volunteers with no psychiatric history.

RESULTS

VBM showed decreases in GM of BPII patients, compared to controls, which were diffuse in nature and most prominent in the right middle frontal gyrus and in the right superior temporal gurus. DTI showed significant and widespread FA reduction in BPII patients in all major WM tracts, including cortico-cortical association tracts.

LIMITATIONS

The small sample size limits the generalisability of our findings.

CONCLUSIONS

Reduced GM volumes and WM integrity changes in BPII patients are not prominent like those previously reported in bipolar disorder type-I and involve cortical structures and their related association tracts.

A quantitative review of neurocognition in euthymic late-life bipolar disorder

OBJECTIVES

A sizeable body of work has consistently documented that a number of euthymic mixed-age bipolar disorder subjects exhibit prominent impairments in a variety of cognitive domains. By contrast, knowledge about neuropsychological functioning in elderly patients is scant, despite being necessary for the adequate treatment of this population and the understanding of illness evolution. The aim of this study was to combine findings from the available literature in order to examine the pattern and extent of cognitive deficits in euthymic late-life bipolar disorder subjects.

METHODS

A literature search was conducted through the online databases PubMed, ScienceDirect, EBSCO, and Wiley-Blackwell, covering the period between January 1990 and April 2012. Effect sizes reflecting patient-control differences for 10 cognitive variables were extracted from selected investigations and combined by means of meta-analytical procedures.

RESULTS

No significant patient-control differences were found for global cognitive status as assessed with the Mini-Mental State Examination and the Clock Drawing Test. Significant overall effect sizes (Hedges' g) of between 0.61 and 0.88 were noted for sustained attention, digit span (forwards and backwards), delayed recall, serial learning, cognitive flexibility, and verbal fluency (phonemic and categorical).

CONCLUSIONS

The extent of cognitive dysfunction in euthymic late-life bipolar disorder subjects may be, on average, similar to that reported for remitted young adult patients. Larger effect sizes of impairment may be associated with late illness onset. Implications and future directions for research are proposed.

Modeling bipolar disorder suicidality

OBJECTIVES

To review the psychosocial, neuropsychological, and neurobiological evidence regarding suicide and bipolar disorder (BD), to enable the development of an integrated model that facilitates understanding, and to provide a useful framework for future research.

METHODS

A two-stage literature review was conducted. First, an electronic literature search was performed using key words (e.g., bipolar disorder, suicide risk, and neuroimaging) and standard databases (e.g., MEDLINE). Second, theoretical suicide models were reviewed, and their evidence base and relevance to BD were evaluated in order to determine a guiding theoretical framework for contextualizing suicide in BD.

RESULTS

Although accumulating clinical, cognitive, and neurobiological correlates of suicide have been identified in BD, extant research has been largely atheoretical. The Cry of Pain (CoP) and an adapted version of the model, the Schematic Appraisals Model of Suicide (SAMS), provide a useful schema for examining vulnerability to suicide in BD, by taking into account biopsychosocial determinants of suicidality. In combination, these also provide a model within which the neural correlates of suicide can be integrated.

CONCLUSIONS

The proposed Bipolar Suicidality Model (BSM) highlights the psychosocial precursors to suicidality in BD, while recognizing the key role of cognitive deficits and underlying functional neurobiological abnormalities. It usefully integrates our knowledge, and provides a novel perspective that is intended to meaningfully inform future research initiatives, and can lead to a better understanding of suicidality in bipolar disorder. Ultimately, it is hoped that it will facilitate the development of targeted interventions that diminish the risk of suicide in bipolar disorder.

Prediction of patient contacts by cognition in schizophrenia

OBJECTIVE

To investigate the correlations between cognitive function and clinical outcome variables.

METHOD

Patients diagnosed for the first time with schizophrenia between January 2004 and June 2010 were cognitively tested in conjunction with diagnostic procedures. Cognitive test data were connected to Danish healthcare registers and patients were followed in the registers from their first contact with psychiatric in- and outpatient care until October 2011.

RESULTS

Patients had impaired attention, processing speed and executive function as measured by Trail Making Test part B; their executive functions, as measured by the Wisconsin Card Sorting Test (WCST), and working memory, as measured by Rigshospitalet's digit span test, were unaffected as compared to norms. The admission rate, from schizophrenia diagnosis to the end of the study, was predicted by Trail Making Test part A, Rey's Auditory Verbal Learning Test (RAVLT), RAVLT (total learning), RAVLT (memory), d2 Test of Attention (total) and d2 type 2 error (error of commission), independent of gender, age and schizophrenia subtype. The length of hospitalization after the schizophrenia diagnosis was mainly determined by the schizophrenia subtype (schizophrenia simplex: incidence rate ratio (IRR) 0.24; 95% confidence interval (CI) 0.15-0.40, p < 0.001). Diagnosis was secondarily determined by deficits in attention and executive function, Trail Making Test part B, d2 Test of Attention (total), d2 type 1 error (error of omission), d2 type 2 error, and also by age and substance use disorder. The outpatient contact rate from schizophrenia diagnosis to the end of the study was predicted by d2 Test of Attention, Trail Making Test part A, and d2 type 2 error. The annual rate of criminal conviction, institutionalization and social retirement pension was mainly predicted by substance misuse.

CONCLUSION

Cognitive function only predicted hospitalization and outpatient contacts to a minor degree in a cohort of newly diagnosed patients with schizophrenia.

P50 sensory gating is a trait marker of the bipolar spectrum

Sensory gating deficit, assessed by a paired auditory stimulus paradigm (P50), has been reported as a stable marker of schizophrenia. The aim of this study was to explore if this neurophysiological disturbance also fulfilled stability criteria in the bipolar disorder (BD) spectrum bipolar, as state independence is one of the main points to be considered as a potential endophenotype of the illness. The P50 evoked potential was studied in 95 healthy controls and 126 bipolar euthymic patients. Euthymia was established according to Van Gorp's criteria. Bipolar I and II subtypes were analyzed separately. The influence of a lifetime history of psychoses was also evaluated in the clinical sample. P50 gating was deficitary in all the subsamples of patients relative to healthy comparison subjects. Bipolar I patients with and without a history of psychosis showed higher P50 ratios than the other subgroups of patients, although these differences were not significant. P50 alterations were mainly due to a deficit in the inhibition of the second wave (test wave or S2) amplitude.

CONCLUSIONS

The findings suggest that this inhibitory deficit can be considered characteristic of the illness and that the intensity of the gating abnormality varies according to the severity of BD.

Neurocognitive function in bipolar disorder: a comparison between bipolar I and II disorder and matched controls

BACKGROUND

Cognitive deficits have been documented in patients with bipolar disorder. Further, it has been suggested that the degree and type of cognitive impairment differ between bipolar I and bipolar II disorder, but data is conflicting and remains inconclusive. This study aimed to clarify the suggested differences in cognitive impairment between patients with bipolar I and II disorder in a relatively large, clinically stable sample while controlling for potential confounders.

METHODS

67 patients with bipolar I disorder, 43 with bipolar II disorder, and 86 randomly selected population-based healthy controls were compared. A number of neuropsychological tests were administered, assessing verbal and visual memory and executive functions. Patients were in a stable phase during testing.

RESULTS

Patients with bipolar type I and type II were cognitively impaired compared to healthy controls, but there were no statistically significant differences between the two subtypes. The strongest predictor of cognitive impairment within the patient group was current antipsychotic treatment.

CONCLUSIONS

The present study suggests that the type and degree of cognitive dysfunction is similar in bipolar I and II patients. Notably, treatment with antipsychotics - but not a history of psychosis - was associated with more severe cognitive impairment. Given that patients with bipolar I disorder are more likely to be on antipsychotic drugs, this might explain why some previous studies have found that patients with type I bipolar disorder are more cognitively impaired than those with type II.

Neurocognitive features in subgroups of bipolar disorder

OBJECTIVE

To examine which subgroups of DSM-IV bipolar disorder (BD) [BD type I (BD-I) or BD type II (BD-II), and subgroups based on history of psychosis, presenting polarity, and age at onset] differentiate best regarding neurocognitive measures.

METHODS

A total of 199 patients with BD were characterized by clinical and neurocognitive features. The distribution of subgroups in this sample was: BD-I, 64% and BD-II, 36%; 60% had a history of psychosis; 57% had depression as the presenting polarity; 61% had an early onset of BD, 25% had a mid onset, and 14% had a late onset. We used multivariate regression analyses to assess relationships between neurocognitive variables and clinical subgroups.

RESULTS

Both BD-I diagnosis and elevated presenting polarity were related to impairments in verbal memory, with elevated presenting polarity explaining more of the variance in this cognitive domain (22.5%). History of psychosis and BD-I diagnosis were both related to impairment in semantic fluency, with history of psychosis explaining more of the variance (11.6%).

CONCLUSION

Poor performance in verbal memory appears to be associated with an elevated presenting polarity, and poor performance in semantic fluency appears to be associated with a lifetime history of psychosis.