Intermediate: cognitive phenotypes in bipolar disorder

Functional characteristics of control adaptation in intermodal sensory processing

The present work investigated functional characteristics of control adjustments in intermodal sensory processing. Subjects performed an interference task that involved simultaneously presented visual and auditory stimuli which were either congruent or incongruent with respect to their response mappings. In two experiments, trial-by-trial sequential congruency effects were analysed for specific conditions that allowed ruling out "non-executive" contributions of stimulus or response priming to the respective RT fluctuations. In Experiment 1, conflict adaptation was observed in an oddball condition in which interference emanates from a task-irrelevant and response-neutral low-frequency stimulus. This finding characterizes intermodal control adjustments to be based - at least partly - on increased sensory selectivity, which is able to improve performance in any kind of interference condition which shares the same or overlapping attentional requirements. In order to further specify this attentional mechanism, Experiment 2 defined analogous conflict adaptation effects in non-interference unimodal trials in which just one of the two stimulus modalities was presented. Conflict adaptation effects in unimodal trials exclusively occurred for unimodal task-switch trials but not for otherwise equivalent task repetition trials, which suggests that the observed conflict-triggered control adjustments mainly consist of increased distractor inhibition (i.e., down-regulation of task-irrelevant information), while attributing a negligible role to target amplification (i.e., enhancement of task-relevant information) in this setup. This behavioral study yields a promising operational basis for subsequent neuroimaging investigations to define brain activations and connectivities which underlie the adaptive control of attentional selection.

Shared dimensions of performance and activation dysfunction in cognitive control in females with mood disorders

Major depressive disorder and bipolar disorder share symptoms that may reflect core mood disorder features. This has led to the pursuit of intermediate phenotypes and a dimensional approach to understand neurobiological disruptions in mood disorders. Executive dysfunction, including cognitive control, may represent a promising intermediate phenotype across major depressive disorder and bipolar disorder. This study examined dimensions of cognitive control in women with major depressive disorder or bipolar disorder in comparison to healthy control subjects using two separate, consecutive experiments. For Experiment 1, participants completed a behavioural cognitive control task (healthy controls = 150, major depressive disorder = 260, bipolar disorder = 202; age range 17-84 years). A sample of those participants (healthy controls = 17, major depressive disorder = 19, and bipolar disorder = 16) completed a similar cognitive control task in an event-related design functional magnetic resonance imaging protocol for Experiment 2. Results for Experiment 1 showed greater impairments on the cognitive control task in patients with mood disorders relative to healthy controls (P < 0.001), with more of those in the mood disorder group falling into the 'impaired' range when using clinical cut-offs (<5th percentile). Experiment 2 revealed only a few areas of shared activation differences in mood disorder greater than healthy controls. Activation analyses using performance as a regressor, irrespective of diagnosis, revealed within and extra-network areas that were more active in poor performers. In summary, performance and activation during cognitive control tasks may represent an intermediate phenotype for mood disorders. However, cognitive control dysfunction is not uniform across women with mood disorders, and activation is linked to performance more so than disease. These findings support subtype and dimensional approaches to understanding risk and expression of mood disorders and are a promising area of inquiry, in line with the Research Domain Criteria initiative of NIMH.

Implicit motor learning in bipolar disorder

OBJECTIVES

A growing number of publications describe cerebellar abnormalities in patients with bipolar disorder (BD). The aim of the following paper was to examine the functional aspects of that issue by focusing on implicit learning - a cognitive function with significant cerebellar underpinnings.

METHODS

27 patients with BD and 26 healthy controls (HC), matched for age and sex took part in the study. Implicit motor learning was assessed by the serial reaction time task (SRTT), in which participants were unconsciously learning a sequence of motor reactions. The indicators of procedural learning were the decrease of reaction time (RT) across the repetition of the sequence and the rebound of RT when the sequence changed into a random set of stimuli.

RESULTS

BD patients did not present any indicators of the implicit learning, their RT increased across repetitions of the sequence and it decreased when the sequence changed to random. Contrary, in the control group RT decreased across the sequence repetitions and increased when the stimuli begun to appear randomly.

LIMITATIONS

A low subject count and a non-drug naïve patients group, medicated with atypical antipsychotic and mood stabilizers, are the most significant limitations of this study.

CONCLUSIONS

BD patients did not acquire procedural knowledge while performing the task, whereas HC did. To our knowledge this is the first study that shows the impairment of implicit motor learning in patients with BD. This indicates the possible cerebellar dysfunction in this disease and may provide a new neuropsychiatric approach to bipolar disorder.

Cognitive control of gaze in bipolar disorder and schizophrenia

The objective of the present study was to compare two components of executive functioning, response monitoring and inhibition, in bipolar disorder (BP) and schizophrenia (SZ). The saccadic countermanding task is a translational paradigm optimized for detecting subtle abnormalities in response monitoring and response inhibition. We have previously reported countermanding performance abnormalities in SZ, but the degree to which these impairments are shared by other psychotic disorders is unknown. 18 BP, 17 SZ, and 16 demographically matched healthy controls (HC) participated in a saccadic countermanding task. Performance on the countermanding task is approximated as a race between movement generation and inhibition processes; this model provides an estimate of the time needed to cancel a planned movement. Response monitoring was assessed by the reaction time (RT) adjustments based on trial history. Like SZ patients, BP patients needed more time to cancel a planned movement. The two patient groups had equivalent inhibition efficiency. On trial history-based RT adjustments, however, we found a trend towards exaggerated trial history-based slowing in SZ compared to BP. Findings have implications for understanding the neurobiology of cognitive control, for defining the etiological overlap between schizophrenia and bipolar disorder, and for developing pharmacological treatments of cognitive impairments.

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.

Emotion regulation strategies can predict task-switching abilities in euthymic bipolar patients

This study examined task-switching abilities and emotion regulation strategies in euthymic bipolar patients (EBP). Forty EBP and 40 healthy individuals performed face categorization tasks where they switched between emotion and non-emotion (i.e., gender) features among faces and completed emotion regulation questionnaire (Gross and John, 2003). Subject groups showed substantial differences in task-switching abilities and emotion regulation strategies: (1) there was a dissociation between emotion and gender classification in EBP. The switch cost was larger [i.e., higher reaction times (RTs) on switch as compared to no-switch trials] for gender categorization as compared to the emotion categorization task. In contrast, such asymmetries were absent among healthy participants. The differential pattern of task switching reflected functional disturbances in frontotemporal neural system and an attentional bias to emotion features of the faces in EBP. This suggests that when a euthymic bipolar patient is preoccupied with emotion recognition, an instruction to perform gender categorization results in greater cost on RTs. (2) In contrast to healthy individuals, EBP reported more frequent use of emotion suppression and lesser use of cognitive reappraisal as emotion regulation strategy. (3) Emotion regulation was found to be a significant predictor of task-switching abilities. It is argued that task switching deficits rely on maladaptive emotion regulation strategies in EBP specifically when tasks of emotional significance are involved.

Openness predicts cognitive functioning in bipolar disorder

OBJECTIVES

Openness to experience (O) is a well-established personality factor and is associated with cognitive performance. Little is known about the personality-cognitive relationship in bipolar disorder, an illness with significant variability in mood. Cognitive evaluation is essential in psychopathology assessment as it may reflect underlying disease processes and psychosocial functional capacity. Screening using a proxy personality variable may identify those in need of comprehensive cognitive testing. We hypothesized that O and measures of cognition would associate in both the Bipolar Disorder (BD) and healthy control (HC) samples, whereas neuroticism and extraversion would correlate with cognition only in the BD sample.

METHODS

Data from a longitudinal study of BD were used to study the association between personality factors and cognitive measures of attention, executive functioning, memory and fine motor skills. Regression analyses were used to determine the variables that account for the association between personality and cognition.

RESULTS

Aspects of O explained significant cognitive variance (~5%) in both groups; this persisted when demographic variables (including BD versus HC status) were considered. Neuroticism and extraversion did not consistently correlate with cognitive performance in either group.

LIMITATIONS

There were more females in the HC group who were slightly younger compared to the BD group. We lack direct measures of positive affect, and there is a reliance on a single measure of personality.

CONCLUSIONS

BD Individuals scoring low on self-reported Openness are potential candidates for more comprehensive cognitive assessments (which represent a limited resource).

Dietary intake and plasma metabolomic analysis of polyunsaturated fatty acids in bipolar subjects reveal dysregulation of linoleic acid metabolism

Polyunsaturated fatty acids (PUFA) profiles associate with risk for mood disorders. This poses the hypothesis of metabolic differences between patients and unaffected healthy controls that relate to the primary illness or are secondary to medication use or dietary intake. However, dietary manipulation or supplementation studies show equivocal results improving mental health outcomes. This study investigates dietary patterns and metabolic profiles relevant to PUFA metabolism, in bipolar I individuals compared to non-psychiatric controls. We collected seven-day diet records and performed metabolomic analysis of fasted plasma collected immediately after diet recording. Regression analyses adjusted for age, gender and energy intake found that bipolar individuals had significantly lower intake of selenium and PUFAs, including eicosapentaenoic acid (EPA) (n-3), docosahexaenoic acid (DHA) (n-3), arachidonic acid (AA) (n-6) and docosapentaenoic acid (DPA) (n-3/n-6 mix); and significantly increased intake of the saturated fats, eicosanoic and docosanoic acid. Regression analysis of metabolomic data derived from plasma samples, correcting for age, gender, BMI, psychiatric medication use and dietary PUFA intake, revealed that bipolar individuals had reduced 13S-HpODE, a major peroxidation product of the n-6, linoleic acid (LA), reduced eicosadienoic acid (EDA), an elongation product of LA; reduced prostaglandins G2, F2 alpha and E1, synthesized from n-6 PUFA; and reduced EPA. These observations remained significant or near significant after Bonferroni correction and are consistent with metabolic variances between bipolar and control individuals with regard to PUFA metabolism. These findings suggest that specific dietary interventions aimed towards correcting these metabolic disparities may impact health outcomes for individuals with bipolar disorder.

The double burden of age and disease on cognition and quality of life in bipolar disorder

OBJECTIVE

Bipolar disorder (BPD) and normal aging are known to impact cognitive skills and health-related quality of life (HRQOL). This study investigated how aging and disease interact in predicting cognitive and psychosocial outcomes.

METHODS

Eight cognitive and ten subjective HRQOL domain ratings were measured. Subjects included 80 young (18-29 years) and late middle-aged (50-65 years) BPD patients in the euthymic phase and 70 age-equivalent healthy comparison participants.

RESULTS

An age X disease interaction was detected in three domains of cognitive functioning that reflect emotion processing, processing speed, and executive functioning skills, with BPD patients in the older group performing most poorly. There was a double burden of aging and disease on reported ability to perform physical tasks. However, regardless of age, disease status was associated with lower ratings of HRQOL in the psychosocial/affective sphere and the majority of cognitive domains. Post hoc analyses revealed that number of years ill was positively associated with select HRQOL ratings in older, but not younger BPD adults.

CONCLUSIONS

These findings may stimulate future longitudinal study of cognition and quality of life in BPD patients across the life span, focusing on additive and interactive effects of aging and disease burden, which could culminate in developing more effective treatment and rehabilitation strategies for this traditionally challenging to treat population.

Common and disease-specific dysfunctions of brain systems underlying attentional and executive control in schizophrenia and bipolar disorder

Schizophrenia and bipolar disorder broadly overlap in multiple areas involving clinical phenomenology, genetics, and neurobiology. Still, the investigation into specific elementary (sub-)processes of executive functioning may help to define clear points of distinction between these categorical diagnoses to validate the nosological dichotomy and, indirectly, to further elucidate their pathophysiological underpinnings. In the present behavioral study, we sought to separate common from diagnosis-specific deficits in a series of specific elementary sub-functions of executive processing in patients with schizophrenia and bipolar disorder. For our purpose, we administered a modern and multi-purpose neuropsychological task paradigm to equal-sized and matched groups of schizophrenia patients, patients with bipolar disorder, and healthy control subjects. First, schizophrenia patients compared to the bipolar group exhibited a more pronounced deficit in general measures of task performance comprising both response speed and accuracy. Additionally, bipolar patients showed increased advance task preparation, i.e., were better able to compensate for response speed deficits when longer preparation intervals were provided. Set-shifting, on the other hand, was impaired to a similar degree in both patient groups. Finally, schizophrenia patients exhibited a specific deficit in conflict processing (inhibitory control) and the shielding of task-relevant processing from distraction (i.e., attentional maintenance). The present investigation suggests that specific neuropsychological measures of elementary executive functions may represent important points of dissociation between schizophrenia and bipolar disorder, which may help to differentiate the pathophysiological underpinnings of these major psychiatric disorders. In this context, the present findings highlight the measures of inhibitory control and attentional maintenance as promising candidates.

Investigating facial affect processing in psychosis: a study using the Comprehensive Affective Testing System

Facial affect processing (FAP) deficits in schizophrenia (SZ) and bipolar disorder (BD) have been widely reported; although effect sizes vary across studies, and there are limited direct comparisons of the two groups. Further, there is debate as to the influence of both psychotic and mood symptoms on FAP. This study aimed to address these limitations by recruiting groups of psychosis patients with either a diagnosis of SZ or BD and comparing them to healthy controls (HC) on a well validated battery of four FAP subtests: affect discrimination, name affect, select affect and match affect. Overall, both groups performed more poorly than controls in terms of accuracy. In SZ, this was largely driven by impairments on three of the four subtests. The BD patients showed impaired performance specifically on the match affect subtest, a task that had a high cognitive load. FAP performance in the psychosis patients was correlated with severity of positive symptoms and mania. This study confirmed that FAP deficits are a consistent finding in SZ that occur independent of task specific methodology; whilst FAP deficits in BD are more subtle. Further work in this group is needed to replicate these results.

Dissociating effects of spatial learning from locomotor activity for ouabain-induced bipolar disorder-like rats

Whether ouabain, a Na+ - and K+-activated adenosine triphosphatase inhibitor, mimics cognitive impairments that can be dissociated from motor effects in the bipolar disorder-like animal model remains unclear. Ouabain and the vehicle aCSF were microinjected into the left lateral ventricle immediately, after 4h, and after 24h. The results showed that (a) locomotion responses of the Immediate group were significantly decreased compared to those of the aCSF group, particularly the first five minutes. (b) The ouabain-treated rats have longer latency and total distance traveled in the water maze task; however, the velocity was not affected for the ouabain group. (c) The analysis of covariance showed that the latency time (but not the total distance traveled and velocity) of the ouabain group was more impaired than that of the aCSF group, regardless of omitting total distance traveled and cross movement in the open field test. The latency might be more sensitive than the distance traveled and the velocity for assessing spatial learning. Dissociating the spatial learning from the movement may allow testing drug treatments of cognitive deficits independent of locomotor effects associated with bipolar disorder.

ECOLOGICALLY VALID LONG-TERM MOOD MONITORING OF INDIVIDUALS WITH BIPOLAR DISORDER USING SPEECH

Speech patterns are modulated by the emotional and neurophysiological state of the speaker. There exists a growing body of work that computationally examines this modulation in patients suffering from depression, autism, and post-traumatic stress disorder. However, the majority of the work in this area focuses on the analysis of structured speech collected in controlled environments. Here we expand on the existing literature by examining bipolar disorder (BP). BP is characterized by mood transitions, varying from a healthy euthymic state to states characterized by mania or depression. The speech patterns associated with these mood states provide a unique opportunity to study the modulations characteristic of mood variation. We describe methodology to collect unstructured speech continuously and unobtrusively via the recording of day-to-day cellular phone conversations. Our pilot investigation suggests that manic and depressive mood states can be recognized from this speech data, providing new insight into the feasibility of unobtrusive, unstructured, and continuous speech-based wellness monitoring for individuals with BP.

Metabolic syndrome in bipolar disorder and schizophrenia: dietary and lifestyle factors compared to the general population

OBJECTIVE

Since a poor diet is often cited as a contributor to metabolic syndrome for subjects diagnosed with bipolar disorder and schizophrenia, we sought to examine dietary intake, cigarette smoking, and physical activity in these populations and compare them with those for the general population.

METHODS

Individuals diagnosed with bipolar disorder (n = 116) and schizophrenia (n = 143) were assessed for dietary intake, lifestyle habits, and metabolic syndrome and compared to age-, gender-, and race-matched subjects from the National Health and Nutrition Examination Survey (NHANES) 1999-2000. Additionally, matched subgroups within the patient populations were compared to elicit any differences.

RESULTS

As expected, the metabolic syndrome rate was higher in the samples with bipolar disorder (33%) and schizophrenia (47%) compared to matched NHANES controls (17% and 11%, respectively), and not different between the patient groups. Surprisingly, both subjects with bipolar disorder and those with schizophrenia consumed fewer total calories, carbohydrates and fats, as well as more fiber (p < 0.03), compared to NHANES controls. No dietary or activity differences between patient participants with and without metabolic syndrome were found. Subjects with schizophrenia had significantly lower total and low-density cholesterol levels (p < 0.0001) compared to NHANES controls. Subjects with bipolar disorder smoked less (p = 0.001), exercised more (p = 0.004), and had lower body mass indexes (p = 0.009) compared to subjects with schizophrenia.

CONCLUSIONS

Counter to predictions, few dietary differences could be discerned between schizophrenia, bipolar disorder, and NHANES control groups. The subjects with bipolar disorder exhibited healthier behaviors than the patients with schizophrenia. Additional research regarding metabolic syndrome mechanisms, focusing on non-dietary contributions, is needed.

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.

Transcripts involved in calcium signaling and telencephalic neuronal fate are altered in induced pluripotent stem cells from bipolar disorder patients

Bipolar disorder (BP) is a chronic psychiatric condition characterized by dynamic, pathological mood fluctuations from mania to depression. To date, a major challenge in studying human neuropsychiatric conditions such as BP has been limited access to viable central nervous system tissue to examine disease progression. Patient-derived induced pluripotent stem cells (iPSCs) now offer an opportunity to analyze the full compliment of neural tissues and the prospect of identifying novel disease mechanisms. We have examined changes in gene expression as iPSC derived from well-characterized patients differentiate into neurons; there was little difference in the transcriptome of iPSC, but BP neurons were significantly different than controls in their transcriptional profile. Expression of transcripts for membrane bound receptors and ion channels was significantly increased in BP-derived neurons compared with controls, and we found that lithium pretreatment of BP neurons significantly altered their calcium transient and wave amplitude. The expression of transcription factors involved in the specification of telencephalic neuronal identity was also altered. Control neurons expressed transcripts that confer dorsal telencephalic fate, whereas BP neurons expressed genes involved in the differentiation of ventral (medial ganglionic eminence) regions. Cells were responsive to dorsal/ventral patterning cues, as addition of the Hedgehog (ventral) pathway activator purmorphamine or a dorsalizing agent (lithium) stimulated expression of NKX2-1 (ventral identity) or EMX2 (dorsal) in both groups. Cell-based models should have a significant impact on our understanding of the genesis and therefore treatment of BP; the iPSC cell lines themselves provide an important resource for comparison with other neurodevelopmental disorders.

Benzodiazepines, benzodiazepine-like drugs, and typical antipsychotics impair manual dexterity in patients with schizophrenia

Impaired dexterity is a major psychomotor deficit reported in patients with schizophrenia. In the present study, the Purdue pegboard test was used to compare the manual dexterity in patients with schizophrenia and healthy controls. We also examined the influence of antipsychotics, benzodiazepines, and benzodiazepine-like drugs on manual dexterity. Subjects were 93 patients with schizophrenia and 93 healthy controls, matched for sex and age distributions. Control subjects scored significantly higher on all scores of Purdue pegboard than patients with schizophrenia. Age, PANSS negative symptom scale, typical antipsychotic dose, and use of benzodiazepines and/or benzodiazepine-like drugs were negatively correlated with the pegboard scores in patients with schizophrenia. The present results indicate that patients with schizophrenia have impaired gross and fine fingertip dexterity compared to healthy controls. The use of typical antipsychotics and benzodiazepines and/or benzodiazepine-like drugs, but not atypical antipsychotics, had significant negative impact on dexterity in patients with schizophrenia. Psychiatrists should be aware that some psychotropic medications may enhance the disability caused by the impairment of dexterity in patients with schizophrenia.

Investigating affective prosody in psychosis: a study using the Comprehensive Affective Testing System

Affective prosody is substantially impaired in schizophrenia, yet little is known about affective prosody in bipolar disorder (BD). The aim of this study was to examine affective prosody performance in schizophrenia, schizoaffective disorder and BD on a newly released standardised assessment to further our understanding of BD performance. Fifty-four schizophrenia, 11 schizoaffective and 43 BD patients were compared with 112 healthy controls (HC) on four affective prosody subtests of the Comprehensive Affective Testing System (CATS). Schizophrenia patients showed a 10% reduction in accuracy on two subtests compared to HC. BD showed a trend for performance intermediary to schizophrenia and HC; and schizoaffective patients performed more like HC on these four affective prosody measures. Severity of current auditory hallucination, across all patients, was related to task performance on three of the measures. These data confirm that schizophrenia and BD have reduced affective prosody performance, with deficits in BD being less pronounced than schizophrenia. The schizoaffective results in this study should be interpreted with caution due to small sample size.

Emotion perception and executive functioning predict work status in euthymic bipolar disorder

Functional recovery, including return to work, in Bipolar Disorder (BD) lags behind clinical recovery and may be incomplete when acute mood symptoms have subsided. We examined impact of cognition on work status and underemployment in a sample of 156 Euthymic-BD and 143 controls (HC) who were divided into working/not working groups. Clinical, health, social support, and personality data were collected, and eight cognitive factors were derived from a battery of neuropsychological tests. The HC groups outperformed the BD groups on seven of eight cognitive factors. The working-BD group outperformed the not working-BD group on 4 cognitive factors composed of tasks of emotion processing and executive functioning including processing speed and set shifting. Emotion processing and executive tasks were predictive of BD unemployment, after accounting for number of mood episodes. Four cognitive factors accounted for a significant amount of the variance in work status among the BD participants. Results indicate that patients with BD who are unemployed/unable to work exhibit greater difficulties processing emotional information and on executive tasks that comprise a set shifting or interference resolution component as compared to those who are employed, independent of other factors. These cognitive and affective factors are suggested as targets for treatment and/or accommodations.

Affect recognition across manic and euthymic phases of bipolar disorder in Han-Chinese patients

Patients with bipolar disorder (BD) have affect recognition deficits. Whether affect recognition deficits constitute a state or trait marker of BD has great etiopathological significance. The current study aims to explore the interrelationships between affect recognition and basic neurocognitive functions for patients with BD across different mood states, using the Diagnostic Analysis of Non-Verbal Accuracy-2, Taiwanese version (DANVA-2-TW) as the index measure for affect recognition. To our knowledge, this is the first study examining affect recognition deficits of BPD across mood states in the Han Chinese population. Twenty-nine manic patients, 16 remitted patients with BD, and 40 control subjects are included in the study. Distinct association patterns between affect recognition and neurocognitive functions are demonstrated for patients with BD and control subjects, implicating alternations in emotion associated neurocognitive processing. Compared to control subjects, manic patients but not remitted subjects perform significantly worse in the recognition of negative emotions as a whole and specifically anger, after adjusting for differences in general intellectual ability and basic neurocognitive functions. Affect recognition deficit may be a relatively independent impairment in BD rather than consequences arising from deficits in other basic neurocognition. The impairments of manic patients in the recognition of negative emotions, specifically anger, may further our understanding of core clinical psychopathology of BD and have implications in treating bipolar patients across distinct mood phases.

Is aberrant functional connectivity a psychosis endophenotype? A resting state functional magnetic resonance imaging study

BACKGROUND

Schizophrenia and bipolar disorder share overlapping symptoms and risk genes. Shared aberrant functional connectivity is hypothesized in both disorders and in relatives.

METHODS

We investigated resting state functional magnetic resonance imaging in 70 schizophrenia and 64 psychotic bipolar probands, their respective first-degree relatives (n = 70 and 52), and 118 healthy subjects. We used independent component analysis to identify components representing various resting state networks and assessed spatial aspects of functional connectivity within all networks. We first investigated group differences using five-level, one-way analysis of covariance (ANCOVA), followed by post hoc t tests within regions displaying ANCOVA group differences and correlation of such functional connectivity measures with symptom ratings to examine clinical relationships.

RESULTS

Seven networks revealed abnormalities (five-level one-way ANCOVA, family-wise error correction p < .05): A) fronto-occipital, B) midbrain/cerebellum, C) frontal/thalamic/basal ganglia, D) meso/paralimbic, E) posterior default mode network, F) fronto-temporal/paralimbic and G) sensorimotor networks. Abnormalities in networks B and F were unique to schizophrenia probands. Furthermore, abnormalities in networks D and E were common to both patient groups. Finally, networks A, C, and G showed abnormalities shared by probands and their relative groups. Negative correlation with Positive and Negative Syndrome Scale negative and positive scores were found in regions within network C and F respectively, and positive correlation with Positive and Negative Syndrome Scale negative scores was found in regions in network D among schizophrenia probands only.

CONCLUSIONS

Schizophrenia, psychotic bipolar probands, and their relatives share both unique and overlapping within-network brain connectivity abnormalities, revealing potential psychosis endophenotypes.

Sleep quality during euthymia in bipolar disorder: the role of clinical features, personality traits, and stressful life events

Background

Poor sleep quality is known to precede the onset of mood episodes and to be associated with poor treatment outcomes in bipolar disorder (BD). We sought to identify modifiable factors that correlate with poor sleep quality in BD independent of residual mood symptoms.

Methods

A retrospective analysis was conducted to assess the association between the Pittsburgh Sleep Quality Index and clinical variables of interest in euthymic patients with DSM-IV BD (n = 119) and healthy controls (HC; n = 136) participating in the Prechter Longitudinal Study of Bipolar Disorder. Multivariable linear regression models were constructed to investigate the relationship between sleep quality and demographic and clinical variables in BD and HC participants. A unified model determined independent predictors of sleep quality.

Results and discussion

Euthymic participants with BD and HC differed in all domains. The best fitting unified multivariable model of poor sleep quality in euthymic participants with BD included rapid cycling (β = .20, p = .03), neuroticism (β = .28, p = 2 × 10⁻³), and stressful life events (β = .20, p = .02). Poor sleep quality often persists during euthymia and can be a target for treatment. Clinicians should remain vigilant for treating subjective sleep complaints independent of residual mood symptoms in those sensitive to poor sleep quality, including individuals with high neuroticism, rapid cycling, and recent stressful life events. Modifiable factors associated with sleep quality should be targeted directly with psychosocial or somatic treatment. Sleep quality may be a useful outcome measure in BD treatment studies.

Is the non-verbal behavioural emotion-processing profile of bipolar disorder impaired? A critical review

OBJECTIVE

Growing evidence suggests that patients with bipolar disorder (BD) are impaired in their ability to process non-verbal emotion, although few comprehensive reviews of the behavioural literature exist, and there has been little consideration of methodological issues that may account for discrepant empirical findings. This review examines the behavioural facial, prosodic and multimodal processing literature in BD and discusses methodological issues in the context of this evidence.

METHOD

Major computer databases including Google Scholar and PsychINFO were consulted to conduct a comprehensive review of quantitative behavioural differences in the emotion-processing literature in BD. Articles were accepted only if the target population sample met criteria for a DSM-III, DSM-IV or ICD-10 diagnosis, and they contained a healthy control group.

RESULTS

The current literature suggests that facial emotion processing is impaired, and there is preliminary evidence for some behavioural impairment in the processing of emotional prosody.

CONCLUSION

The specificity or generalisability of impairments in facial emotion processing and the effects of mood state are unclear. Similarly, the lack of clarity around the impact of auditory processes on emotional prosody processing warrants a comprehensive examination of the auditory profile in BD.

C9ORF72 expansion in a family with bipolar disorder

OBJECTIVE

To investigate the role in bipolar disorder of the C9ORF72 hexanucleotide repeat expansion responsible for frontotemporal lobe dementia and amyotrophic lateral sclerosis.

METHODS

Eighty-nine subjects from a previously described panel of individuals with bipolar disorder ascertained for genetic studies were screened to detect expansion of the C9ORF72 repeat. One two-generation family with bipolar disorder and an expanded repeat was characterized in depth using molecular diagnostics, imaging, histopathology, and neurological and neuropsychological evaluation.

RESULTS

One proband, with the typical clinical presentation of bipolar disorder, carried an expanded C9ORF72 allele of heterogeneous length between 14 and 20 kilobases (kb) as assessed by Southern blot. The expanded allele was inherited from a parent with atypical, late onset clinical features of bipolar disorder, who subsequently progressed to frontotemporal lobe dementia. The expansion in peripheral blood of the parent ranged from 8.5 to 20 kb. Cultured lymphoblastoid cells from this parent exhibited a homogeneous expansion of only 8.5 kb.

CONCLUSIONS

The disease course in the two generations described here demonstrates that expansion of the C9ORF72 may be associated with a form of bipolar disorder that presents clinically with classic phenomenology and progression to neurodegenerative disease. The frequency in our bipolar disorder cohort was only 1%, indicating that C9ORF72 is not a major contributor to bipolar disorder. DNA from cultured cells may be biased towards shorter repeats and nonrepresentative of the endogenous C9ORF72 expansion.

Genetic and neurocognitive foundations of emotion abnormalities in bipolar disorder

INTRODUCTION

Bipolar Disorder (BD) is a serious mood disorder, the aetiology of which is still unclear. The disorder is characterised by extreme mood variability in which patients fluctuate between markedly euphoric, irritable, and elevated states to periods of severe depression. The current research literature shows that BD patients demonstrate compromised neurocognitive ability in addition to these mood symptoms. Viable candidate genes implicated in neurocognitive and socioemotional processes may explain the development of these core emotion abnormalities. Additionally, links between faulty neurocognition and impaired socioemotional ability complement genetic explanations of BD pathogenesis. This review examines associations between cognition indexing prefrontal neural regions and socioemotional impairments including emotion processing and regulation. A review of the effect of COMT and TPH2 on these functions is also explored.

METHODS

Major computer databases including PsycINFO, Google Scholar, and Medline were consulted in order to conduct a comprehensive review of the genetic and cognitive literature in BD.

RESULTS

This review determines that COMT and TPH2 genetic variants contribute susceptibility to abnormal prefrontal neurocognitive function which oversees the processing and regulation of emotion. This provides for greater understanding of some of the emotional and cognitive symptoms in BD.

CONCLUSIONS

Current findings in this direction show promise, although the literature is still in its infancy and further empirical research is required to investigate these links explicitly.

A unique emotional processing profile of euthymic bipolar disorder? A critical review

OBJECTIVES

To undertake a critical review of the literature on emotional processing (EP) in bipolar patients in remission. This literature review focuses on a number of dimensions of EP including facial emotion recognition, emotional memory, affective theory of mind (ToM), affective attention and affective auditory information processing.

METHODS

A systematic search was conducted through PsychINFO and Medline databases to obtain relevant literature. Studies that include behavioural measures of EP were included.

RESULTS

The findings from this review demonstrate that bipolar disorder (BD) patients continue to exhibit some EP deficits during euthymic phases. A number of factors believed to contribute to such findings have been highlighted.

CONCLUSIONS

This review has shed light on some of the conflicting findings reported in the literature and thus offers a more comprehensive profile of euthymic bipolar patients' EP abilities. This information could enrich clinicians' therapeutic efforts to minimise relapse by attending to euthymic bipolar patients' specific emotional processing difficulties.

Greater executive and visual memory dysfunction in comorbid bipolar disorder and substance use disorder

Measures of cognitive dysfunction in Bipolar Disorder (BD) have identified state and trait dependent metrics. An influence of substance abuse (SUD) on BD has been suggested. This study investigates potential differential, additive, or interactive cognitive dysfunction in bipolar patients with or without a history of SUD. Two hundred fifty-six individuals with BD, 98 without SUD and 158 with SUD, and 97 Healthy Controls (HC) completed diagnostic interviews, neuropsychological testing, and symptom severity scales. The BD groups exhibited poorer performance than the HC group on most cognitive factors. The BD with SUD exhibited significantly poorer performance than BD without SUD in visual memory and conceptual reasoning/set-shifting. In addition, a significant interaction effect between substance use and depressive symptoms was found for auditory memory and emotion processing. BD patients with a history of SUD demonstrated worse visual memory and conceptual reasoning skills above and beyond the dysfunction observed in these domains among individuals with BD without SUD, suggesting greater impact on integrative, gestalt-driven processing domains. Future research might address longitudinal outcome as a function of BD, SUD, and combined BD/SUD to evaluate neural systems involved in risk for, and effects of, these illnesses.

Reduced emotion processing efficiency in healthy males relative to females

This study examined sex differences in categorization of facial emotions and activation of brain regions supportive of those classifications. In Experiment 1, performance on the Facial Emotion Perception Test (FEPT) was examined among 75 healthy females and 63 healthy males. Females were more accurate in the categorization of fearful expressions relative to males. In Experiment 2, 3T functional magnetic resonance imaging data were acquired for a separate sample of 21 healthy females and 17 healthy males while performing the FEPT. Activation to neutral facial expressions was subtracted from activation to sad, angry, fearful and happy facial expressions. Although females and males demonstrated activation in some overlapping regions for all emotions, many regions were exclusive to females or males. For anger, sad and happy, males displayed a larger extent of activation than did females, and greater height of activation was detected in diffuse cortical and subcortical regions. For fear, males displayed greater activation than females only in right postcentral gyri. With one exception in females, performance was not associated with activation. Results suggest that females and males process emotions using different neural pathways, and these differences cannot be explained by performance variations.

Differential executive functioning performance by phase of bipolar disorder

OBJECTIVE

This study examined the influence of illness phase on executive functioning performance using factor-derived cognitive scores in a cross-sectional design.

METHODS

Healthy control (HC) subjects (n = 57), and euthymic (E-BD) (n = 117), depressed (D-BD) (n = 73), and hypomanic/mixed (HM/M-BD) (n = 26) patients with bipolar disorder (BD) were evaluated using executive functioning measures (Wisconsin Card Sorting Test, Trail Making Test-Parts A and B, Verbal Fluency, Parametric Go/No-Go, Stroop, and Digit Symbol) comprising Conceptual Reasoning and Set-Shifting (CRSS), Processing Speed with Interference Resolution (PSIR), Verbal Fluency and Processing Speed (VFPS), and Inhibitory Control (IC) factor scores.

RESULTS

Two of the four executive functioning factors were significantly different between groups based upon phase of illness. The HM/M group was significantly worse than both of the other BD groups and the HC group in IC. The VFPS factor was sensitive to the active phase of BD, with the HM/M-BD and D-BD groups worse than HC. Extending our prior work, the PSIR factor, and now the CRSS factor were significantly worse in BD relative to HC, irrespective of phase of illness.

CONCLUSIONS

Phase of illness had differential cognitive profiles in executive functioning factors, even after considering and excluding the impact of clinical features, illness characteristics, medications, and demographics. Consolidating executive functioning tasks into reliable factor scores provides unique information to measure and define cognitive deficiencies throughout phases of BD, and to measure intermediate phenotypes in BD, and may aid in tracking and clarifying treatment focus.

Abnormal anterior cingulate cortical activity during emotional n-back task performance distinguishes bipolar from unipolar depressed females

BACKGROUND

Depression in the context of bipolar disorder (BDd) is often misdiagnosed as unipolar disorder depression (UDd) leading to poor clinical outcomes for many bipolar sufferers. We examined neural circuitry supporting emotion regulation in females with either BDd or UDd as a first stage toward identifying biomarkers that may differentiate BDd from UDd.

METHOD

Fifty-seven females aged 18-45 years participated in this study: 23 with UDd, 18 with bipolar disorder type I depression (BDId) and 16 healthy females. During 3-T functional magnetic resonance imaging (fMRI), the participants performed an emotional face n-back (EFNBACK) task, that is an n-back task with high (2-back) and low (0-back) memory load conditions flanked by two positive, negative or neutral face distracters. This paradigm examines executive control with emotional distracters-emotion regulation.

RESULTS

High memory load with neutral face distracters elicited greater bilateral and left dorsal anterior midcingulate cortex (dAMCC) activity in UDd than in healthy and BDId females respectively, and greater bilateral putamen activity in both depressed groups versus healthy females. High memory load with happy face distracters elicited greater left putamen activity in UDd than in healthy females. Psychotropic medication was associated with greater putamen activity to these contrasts in UDd females.

CONCLUSIONS

During high memory load with neutral face distracters, elevated dAMCC activity in UDd suggests abnormal recruitment of attentional control circuitry to maintain task performance, whereas elevated putamen activity unrelated to psychotropic medication in BDId females may suggest an attentional bias toward ambiguous neutral face distracters. Differential patterns of functional abnormalities in neural circuitry supporting attentional control during emotion regulation, especially in the dAMCC, is a promising neuroimaging measure to distinguish UDd from BDId in females.

Neuropsychological performance in bipolar I, bipolar II and unipolar depression patients: a longitudinal, naturalistic study

BACKGROUND

It has been suggested that cognitive deficits existed in mood disorders. Nevertheless, whether neuropsychological profiles differ three main subtypes of mood disorder (Bipolar I, Bipolar II and UP) remain understudied because most current studies include either mixed samples of bipolar I and bipolar II patients or mixed samples of different states of the illness. The main aim of the present study is to determine whether, or to some extent, specific cognitive domains could differentiate the main subtypes of mood disorders in the depressed and clinically remitted status.

METHOD

Three groups of bipolar I (n=92), bipolar II (n=131) and unipolar depression (UP) patients (n=293) were tested with a battery of neuropsychological tests both at baseline (during a depressive episode) and after 6 weeks of treatment, contrasting with 202 healthy controls on cognitive performance. The cognitive domains include processing speed, attention, memory, verbal fluency and executive function.

RESULTS

At the acute depressive state, the three patient groups (bipolar I, bipolar II and UP) showed cognitive dysfunction in processing speed, memory, verbal fluency and executive function but not in attention compared with controls. Post comparisons revealed that bipolar I depressed patients performed significantly worse in verbal fluency and executive function than bipolar II and UP depressed patients. No difference was found between bipolar II and UP depressed patients except for the visual memory. After 6 weeks of treatment, clinically remitted bipolar I and bipolar II patients only displayed cognitive impairment in processing speed and visual memory. Remitted UP patients showed cognitive impairment in executive function in addition to processing speed and visual memory. The three remitted patient groups scored similarly in processing speed and visual memory.

LIMITATION

Clinically remitted patients were just recovered from a major depressive episode after 6 weeks of treatment and in relatively unstable state.

CONCLUSION

Bipolar I, bipolar II and UP patients have a similar pattern of cognitive impairment during the state of acute depressive episode, but bipolar I patients experience greater impairment than bipolar II and UP patients. In clinical remission, both bipolar and UP patients show cognitive deficits in processing speed and visual memory, and executive dysfunction might be a status-maker for bipolar disorder, but a trait-marker for UP.

More severe impairment of manual dexterity in bipolar disorder compared to unipolar major depression

BACKGROUND

Mood disorders are associated with various neurocognitive deficits. However, few studies have reported the impairment of motor dexterity in unipolar depression and bipolar disorder. In the present study, manual dexterity was compared between unipolar major depression, bipolar disorder, and healthy controls.

METHODS

Manual dexterity was assessed by the Purdue pegboard test in 98 patients with unipolar major depression, 48 euthymic or depressed patients with bipolar disorder, and 158 healthy controls, matched for age and gender.

RESULTS

Compared to healthy controls, sum of the scores of right, left, and both hands subtests (R+L+B) was significantly lower in both patients with unipolar depression and bipolar disorder (P=0.0034 and P<0.0001, respectively). Furthermore, R+L+B was significantly lower in bipolar disorder compared to unipolar depression (P=0.0016). Lithium dose and chlorpromazine equivalent dose of antipsychotics were significantly negatively correlated with some of the subtest scores. On the other hand, depression severity did not significantly correlate with any of the subtest scores. Difference in R+L+B between unipolar depression and bipolar disorder remained statistically significant even after controlling for gender, age, lithium dose, and chlorpromazine equivalent dose (P=0.0028). Limitations Bipolar patients during manic episode were not included in the study.

CONCLUSIONS

Gross movement dexterity was impaired in both patients with unipolar depression and bipolar disorder. The severity of impairment was significantly greater in patients with bipolar disorder. The functional difference between unipolar and bipolar patients may suggest different pathological conditions between the two depressive disorders.

Identifying a cognitive impairment subgroup in adults with mood disorders

BACKGROUND

We hypothesized that only a minority of patients with mood disorders have measurable cognitive impairment, and this minority drives the small-to-medium effect sizes detected in group studies. Removal of this minority from group statistical analyses will illustrate that the majority appear to have broadly normal cognitive functioning.

METHODS

Participants were adults between the ages of 20 and 54, including 659 healthy control subjects, 84 unmedicated outpatients diagnosed with depression, 59 outpatients diagnosed with depression who were on medications at the time of the evaluation, and 43 outpatients with bipolar disorder. All completed the CNS Vital Signs computerized cognitive screening battery.

RESULTS

The prevalence rates of low cognitive test scores were calculated for the healthy control subjects and the patients with mood disorders. Having two scores at or below the 5th percentile occurred in 31.2% of the patients and only 8.2% of the control subjects [χ(2)(1)=66.67, p<.0001; Odds Ratio=5.1, 95% CI=3.4-7.7]. For the control subjects, this low false positive rate for cognitive impairment was maintained across age groups, sexes, and education levels. A larger proportion of patients with bipolar disorder (41.9%) than patients with depression (27.1-28.6%) met this criterion for cognitive impairment.

CONCLUSIONS

This study suggests that cognitive impairment associated with mood disorders is limited to a minority of patients with the majority being broadly cognitively normal. Future research should determine if this identified subgroup has neuroanatomical, neurophysiological, or neuroendocrine abnormalities. Cognitive screening tools of this type might be useful in selecting participants for studies.

Modality-specific alterations in the perception of emotional stimuli in Bipolar Disorder compared to Healthy Controls and Major Depressive Disorder

OBJECTIVES

Affect identification accuracy paradigms have increasingly been utilized to understand psychiatric illness including Bipolar Disorder (BD) and Major Depressive Disorder (MDD). This investigation focused on perceptual accuracy in affect identification in both visual and auditory domains among patients with BD, relative to Healthy Controls (HC) and patients with MDD. Demographic and clinical variables, in addition to medications were also investigated.

METHOD

The visual Facial Emotion Perception Test (FEPT) and auditory Emotional Perception Test (EPT) were administered to adults with BD (n=119) and MDD (n=78) as well as HC (n=66).

RESULTS

Performance on the FEPT was significantly stronger than on the EPT irrespective of group. Performance on the EPT did not significantly differentiate the groups. On the FEPT, BD samples had the greatest difficulty relative to HC in identification of sad and fearful faces. BD participants also had greater difficulty identifying sad faces relative to MDD participants though not after controlling for severity of illness factors. For the BD (but not MDD) sample several clinical variables were also correlated with FEPT performance.

CONCLUSIONS

The findings suggest that disruptions in identification of negative emotions such as sadness and fear may be a characteristic trait of BD. However, this effect may be moderated by greater illness severity found in our BD sample.