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

Trajectories of quality of life and cognition in different multimorbidity patterns: Evidence from SHARE

OBJECTIVES

The study aimed to observe the trajectory of quality of life (QoL) and cognition, and to a analyze the bidirectional association between cognition and QoL for diverse multimorbidity patterns.

METHODS

In total, 16,153 older participants age ≥50 years were included from the Survey of Health, Ageing and Retirement in Europe (SHARE). We used latent class analysis (LCA) to identify multimorbidity patterns in the baseline population. We used linear mixed models (LMM) to examine the trajectory of cognition and QoL in different multimorbidity patterns. A cross-lagged model was employed to analyze the bidirectional association between cognition and QoL in diverse multimorbidity patterns.

RESULTS

Latent class analysis identified four multimorbidity patterns: high and low comorbidity burden (HC and LC), cardiometabolic (CA), and osteoarthrosis (OS). The HC group had the poorest cognitive function and QoL (p for trend < 0.001). Delayed and immediate episodic memory in the OS group declined at a highest rate (p for trend < 0.001). Additionally, a bidirectional association between cognition and QoL was observed. The effect of cognitive function on QoL was relatively stronger than the reverse in the CA and LC groups.

CONCLUSIONS

The rate of decline in cognition and QoL over the time differs in diverse multimorbidity patterns, and patients with four or more chronic diseases should be specially considered. Notably, early monitoring of cognitive function and can help break the vicious cycle between cognitive deterioration and poor QoL in patients with OS or CA diseases.

Interactive relationships of Type 2 diabetes and bipolar disorder with cognition: evidence of putative premature cognitive ageing in the UK Biobank Cohort

Type 2 diabetes (T2D) is disproportionately prevalent in bipolar disorder (BD) and is associated with cognitive deficits in psychiatrically healthy cohorts. Whether there is an interaction effect between T2D and BD on cognition remains unclear. Using the UK Biobank, we explored interactions between T2D, BD and cognition during mid and later life; and examined age-related cognitive performance effects in BD as a function of T2D. Data were available for 1511 participants with BD (85 T2D), and 81,162 psychiatrically healthy comparisons (HC) (3430 T2D). BD and T2D status were determined by validated measures created specifically for the UK Biobank. Diagnostic and age-related associations between T2D status and cognition were tested using analyses of covariance or logistic regression. There was a negative association of T2D with visuospatial memory that was specific to BD. Processing speed and prospective memory performance were negatively associated with T2D, irrespective of BD diagnosis. Cognitive deficits were evident in BD patients with T2D compared to those without, with scores either remaining the same (processing speed) or improving (visuospatial memory) as a function of participant age. In contrast, cognitive performance in BD patients without T2D was worse as participant age increased, although the age-related trajectory remained broadly equivalent to the HC group. BD and T2D associated with cognitive performance deficits across the mid-life period; indicating comorbid T2D as a potential risk factor for cognitive dysfunction in BD. In comparison to BD participants without T2D and HCs, age-independent cognitive impairments in BD participants with comorbid T2D suggest a potential premature deterioration of cognitive functioning compared to what would normally be expected.

Relations of gray matter volume to dimensional measures of cognition and affect in mood disorders

Understanding the relationship between brain measurements and behavioral performance is an important step in developing approaches for early identification of any psychiatric difficulties and interventions to modify these challenges. Conventional methods to identify associations between regional brain volume and behavioral measures are not optimized, either in scale, scope, or specificity. To find meaningful associations between brain and behavior with greater sensitivity and precision, we applied data-driven factor analytic models to identify and extract individual differences in latent cognitive functions embedded across several computerized cognitive tasks. Furthermore, we simultaneously utilized a keyword-based neuroimaging meta-analytic tool (i.e., NeuroSynth), restricted atlas-parcel matching, and factor-analytic models to narrow down the scope of search and to further aggregate gray matter volume (GMV) data into empirical clusters. We recruited an early adult community cross-sectional sample (Total n = 177, age 18-30) that consisted of individuals with no history of any mood disorder (healthy controls, n = 44), those with remitted major depressive disorder (rMDD, n = 104), and those with a diagnosis of bipolar disorder currently in euthymic state (eBP, n = 29). Study participants underwent structural magnetic resonance imaging (MRI) scans and separately completed behavioral testing using computerized measures. Factor-analyzing five computerized tasks used to assess aspects of cognitive and affective processing resulted in seven latent dimensions: (a) Emotional Memory, (b) Interference Resolution, (c) Reward Sensitivity, (d) Complex Inhibitory Control, (e) Facial Emotion Sensitivity, (f) Sustained attention, and (g)Simple Impulsivity/Response Style. These seven dimensions were then labeled with specific keywords which were used to create neuroanatomical maps using NeuroSynth. These masks were further subdivided into GMV clusters. Using regression, we identified GMV clusters that were predictive of individual differences across each of the aforementioned seven cognitive dimensions. We demonstrate that a dimensional approach consistent with core principles of RDoC can be utilized to identify structural variability predictive of critical dimensions of human behavior.

Heterogeneity of psychosocial functioning in patients with bipolar disorder: Associations with sociodemographic, clinical, neurocognitive and biochemical variables

OBJECTIVE

This study aims to identify the functional heterogeneity in fully or partially remitted patients with bipolar disorder and explore the correlations between psychosocial functioning and sociodemographic, clinical, neurocognitive and biochemical variables.

METHODS

One hundred and forty fully or partially remitted patients with bipolar disorder (BD) and seventy healthy controls were recruited. The patients were grouped into different profiles based on the Functioning Assessment Short Test (FAST) domain scores by hierarchical cluster analysis. The characteristics of subgroups and the correlations between psychosocial functioning and sociodemographic, clinical, neurocognitive and biochemical variables in each cluster were then analyzed.

RESULTS

There were three subgroups in fully or partially remitted patients with BD: the lower functioning group (LF), performed global functioning impairments; the moderate functioning group (MF), presented selective impairments in functional domains; and the good functioning subgroup (GF), performed almost intact functioning. Among the three subgroups, there were differences in FAST domains, sociodemographic variables, clinical variables, some neurocognitive domains and several biochemical indexes.

CONCLUSIONS

The study successfully identified three functional subgroups. The characteristics of discrete subgroups and the specific clinical factors, neurocognitive domains and biochemical indexes that are correlated with functional subgroups will allow for making tailored interventions to promote functional recovery and improve the quality of life.

Age moderates the relationship between affective response inhibition and bipolar disorder in adults

BACKGROUND

Patients with bipolar disorder (BD) often have impairments in neurocognition, including affective processing and affective response inhibition. While studies suggest that cognitive control in general may decline with age in BD, less is known about age-related changes in response inhibition to emotionally salient information.

METHODS

258 participants with BD and 54 healthy controls, ages 18-70, completed the Cambridge Neuropsychological Test Automated Battery (CANTAB) Affective Go/No-Go task to assess affective response inhibition to positive and negative valenced stimuli. We examined the relationship between BD and affective response inhibition (number of commission and omission errors and reaction time), as well as a potential moderating effect of age, using mixed effects linear regression models.

RESULTS

The BD group made more omission and commission errors overall than the control group (p < 0.018). We observed a significant 3-way group-by-age-by-valence interaction for reaction time (p = 0.006). Within BD, a slower reaction time to negative than positive stimuli was found in middle and older age groups (p < 0.012), but not in the younger age group. No significant moderating effect of age was observed within the control group.

CONCLUSIONS

These cross-sectional findings indicate that compared with healthy controls, individuals with BD display differential and age-related effects in inhibition to emotionally salient information that is valence-dependent. The observed pattern of a switch in bias from negative to positive stimuli with age in BD may aid in our understanding of the progression of neurocognitive changes with aging in BD, as well as inform targeted treatments for cognitive symptoms.

A Lifespan Model of Interference Resolution and Inhibitory Control: Risk for Depression and Changes with Illness Progression

The cognitive processes involved in inhibitory control accuracy (IC) and interference resolution speed (IR) or broadly - inhibition - are discussed in this review, and both are described within the context of a lifespan model of mood disorders. Inhibitory control (IC) is a binary outcome (success or no for response selection and inhibition of unwanted responses) for any given event that is influenced to an extent by IR. IR refers to the process of inhibition, which can be manipulated by task design in earlier and later stages through use of distractors and timing, and manipulation of individual differences in response proclivity. We describe the development of these two processes across the lifespan, noting factors that influence this development (e.g., environment, adversity and stress) as well as inherent difficulties in assessing IC/IR prior to adulthood (e.g., cross-informant reports). We use mood disorders as an illustrative example of how this multidimensional construct can be informative to state, trait, vulnerability and neuroprogression of disease. We present aggregated data across numerous studies and methodologies to examine the lifelong development and degradation of this subconstruct of executive function, particularly in mood disorders. We highlight the challenges in identifying and measuring IC/IR in late life, including specificity to complex, comorbid disease processes. Finally, we discuss some potential avenues for treatment and accommodation of these difficulties across the lifespan, including newer treatments using cognitive remediation training and neuromodulation.

Weak associations between depressive symptom severity, depressive symptom clusters, and cognitive performance in young to middle-aged men without clinical depression

Evidence suggests different depressive symptoms are related to  specific aspects of cognition, especially in older adults. The current study extended this literature by examining depressive symptom severity, symptom clusters, and cognitive functioning in young-to-middle aged adults. A sample of 2,560 men (mean age = 38.12 ± 2.41 years) withvalid Minnesota Multiphasic Personality Inventories (MMPI) and completed cognitive measures was drawn from a Vietnam veterans study. Bootstrapped regressions examined relationships between cognitive performance, MMPI Depression  scores, and Harris-Lingoes depression subscales after covariate adjustments. Follow-up analyses investigated non-elevated and elevated depressive symptom groups. We found inverse relationships between specific subscales (Subjective Depression and Mental Dullness) and attentional control. No significant relationships were evident for total depressive symptoms or for the group analyses. Findings suggest weak associations between depressive symptoms and cognition in young to middle-aged men without clinical depression, which adds to the literature on inconsistent findings in depressive symptom-cognition relationships.

Quality of life in euthymic bipolar patients: A systematic review and meta-analysis

BACKGROUND

Patients with bipolar disorder, even euthymic, could suffer an impairment in their quality of life compared to healthy controls. Since no previous systematic review and meta-analysis has been conducted, the aim of the current study is to conduct a systematic review and meta-analysis of cross-sectional case-controlled studies on quality of life in adult euthymic Bipolar Disorder patients.

METHODS

A systematic review and meta-analysis that followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) was conducted. Major electronic databases were searched on August 2018 to assess the variables associated with quality of life in euthymic bipolar disorder patients. After selecting case-control studies, data collection, quality assessment and subsequently statistical analysis were done.

RESULTS

66 studies were finally selected for systematic review and meta-analysis. Four different quality of life instruments were used among the different studies. Effect size analysis showed that there were significant differences in quality of life outcomes between euthymic bipolar disorder patients and healthy controls (d=-0.922; SE=0.316; 95%CI=-1.541--0.303; p=.004), with lower quality of life in the euthymic patients. Furthermore, time since euthymia explained 15.62% of variability, and age of control group explained 29.6% of variability. No other moderators were statiscally significant.

LIMITATIONS

The instruments used were heterogeneous. Moreover, the role of other clinical moderators could not be included due to the lack of this information in most of the articles.

CONCLUSIONS

Quality of life is lower in euthymic bipolar patients than in healthy controls. However, longer time in euthymia is associated with better outcomes.

Interplay between pro-inflammatory cytokines, childhood trauma, and executive function in depressed adolescents

BACKGROUND

Pro-inflammatory cytokines have been linked to depression, early childhood trauma, and impairment in executive function in adults. Whether these links are present during adolescence, a time when vulnerability to depression is heightened, a point more proximal to childhood trauma, and a critical period of brain development, is not well understood.

METHOD

Serum levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor alpha (TNF-α) were measured in 70 adolescents aged 12-17, including 40 with a DSM-IV depressive disorder (DEP), a sub-set (n = 22) of whom reported a history of childhood trauma (DEP-T), and 30 healthy controls (HCs). Participants completed performance-based (Parametric Go/No-Go Task) and observer-rated (Behavior Rating Inventory of Executive Function) measures of executive function. Procedures were conducted at a subspecialty clinic (Dec 2015-June 2017).

RESULTS

IL-6 was elevated in DEP and DEP-T adolescents compared to controls (p = .014) and TNF-α was elevated in DEP participants only (p = .040) compared to controls, whereas no group differences were found in IL-1β (p = .829). Additionally, DEP-T participants demonstrated relative deficits in performance-based (p = .044) and observer-rated inhibitory control (p = .049) compared to controls. Across the whole sample, TNF-α was associated with performance-based (r = -0.25, p = .039) and observer-rated (r = 0.32, p = .009) inhibitory control deficits. In subgroup analyses, TNF-α was associated with increased observer-rated inhibitory deficits in DEP, and at the trend level, with reduced inhibitory control performance in DEP-T.

CONCLUSIONS

The current results suggest that inflammation may be a marker of disease processes in adolescent depression. Though longitudinal studies are needed, depressed adolescents with childhood trauma exposure appear to constitute a uniquely vulnerable group in terms of objective risk for executive dysfunction. Immune dysregulation may partly contribute to this risk.

Are affective temperaments determinants of quality of life in euthymic patients with bipolar disorder?

BACKGROUND

Bipolar disorder (BD) is a disabling illness that is associated with low quality of life (QoL). This low QoL goes further than mood episodes, which suggests that stable traits, such as affective temperaments, can cause functional impairment.

OBJECTIVE

Our study analyses the impact of affective temperaments on the Physical Component Summary (PCS) and Mental Component Summary (MCS) of QoL in euthymic BD patients.

METHODS

A multicentre study was conducted in 180 euthymic BD patients and 95 healthy controls. Firstly, statistical analyses were performed to compare QoL and affective temperaments between the two groups. Secondly, Adaptive Lasso Analysis was carried out to identify the potential confounding variables and select the affective temperaments as potential predictors on the PCS and MCS of QoL in BD patients, as well as the control group.

RESULTS

QoL scores in terms of PCS and MCS in BD patients were significantly lower than in healthy individuals. Whereas anxious temperament, anxiety disorder comorbidity, and age were the best predictors of PCS impairment in BD patients, anxious temperament, subclinical depressive symptoms, and age were the best predictors of MCS impairment.

LIMITATIONS

Further longitudinal studies with unaffected high-risk relatives are needed to examine the potential interaction between affective temperament and psychopathology.

CONCLUSIONS

Anxious temperament has an impact on QoL in BD in terms of both the physical component and the mental component. Systematic screening of temperament in BD would give clinicians better knowledge of QoL predictors. Further research should allow more individualized treatment of BD patients based on temperamental factors.

Assessing bipolar disorder in the older adult: the GERI-BD toolbox

INTRODUCTION

The evidence base regarding characteristics of older adults with bipolar disorder (BD) remains limited. The NIH-funded multicenter study Acute Pharmacotherapy of Late-Life Mania (GERI-BD) assessed various clinical domains before and during mood stabilizer treatment in older adults participating in a 9-week, double-blind randomized controlled trial. We describe the rationale for selecting these instruments.

METHODS

Domains and instruments were selected on the basis of the study design and the participants. The investigators' experience in clinical trials involving young adults with BD or older adults with major depressive disorder, along with open studies of older adults with BD, contributed to the selection process.

RESULTS

We identified domains and selected instruments that could be used to assess the participants given their diagnostic, treatment history, and medical and mood state characteristics. They were also intended to measure tolerability and efficacy and permit examination of potential moderating and mediating factors.

CONCLUSIONS

Decisions regarding the assessment domains to be included in the clinical trial highlight the challenges facing researchers studying drug treatments for older adults with BD, or more generally, mood disorders. We suggest that the domains and instruments selected by GERI-BD investigators constitute a "toolbox" that can be customized for other investigators. Copyright © 2017 John Wiley & Sons, Ltd.

Neuropsychological functioning, age, and medication adherence in bipolar disorder

Objectives

Poor adherence to medication is frequent in bipolar disorder (BD) and has been associated with several factors. To date, the relationship between low adherence and neuropsychological functioning in BD is still unclear. As age and neuropsychological functioning might have opposing influences on adherence, our aim was to investigate this link with a particular focus on the effect of age.

Methods

In a cross-sectional study, we included 353 patients divided into two age-groups (16–46; 47–71) from a French cohort diagnosed with BD (type I, II, NOS) and strictly euthymic. All patients had a standardized clinical and neuropsychological assessment and were categorized as high (n = 186) or low (n = 167) adherent based on their score from the Medication Adherence Rating Scale. Clinical information was collected based on a standardized interview and clinical validated scales. Neuropsychological performances were evaluated with an established standardized neuropsychological battery for bipolar disorder patients. After univariate analysis, neuropsychological and clinical predictors of low adherence were included in two age-specific stepwise multiple logistic regressions.

Results

A smaller number of hospitalizations (OR = 0.846, p = 0.012), a shorter illness duration (OR = 0.937, p = 0.003) and higher adverse effects (OR = 1.082, p<0.001) were associated with a greater risk of low adherence in the younger patients. In the older patients, low adherence was also predicted by a smaller number of hospitalizations (OR = 0.727, p = 0.008) and higher adverse effects (OR = 1.124, p = 0.005). Interestingly poor inhibition performance was also a significant predictor of low adherence in older patients (OR = 0.924, p = 0.030).

Conclusions

We found an age-specific relationship between cognitive functioning and adherence in patients with BD. Poor inhibition performances predicted low adherence in older patients only. Our results highlight the need to provide age-adapted therapeutic interventions to improve adherence in patients with BD.

The impact of chronic psychiatric disorders on cognitive decline

OBJECTIVES

Based on seemingly contradictory results in the existing literature, the objective of our study was to investigate whether older individuals suffering from chronic psychiatric disorders show a more rapid decline in cognitive performances than their non-psychiatric counterparts, or if the pattern of decline through older age is similar in both groups.

METHOD

A total of 820 older adults were selected from the Ageing Multidisciplinary Investigation (AMI) cohort study, which studies health-related issues of people over 65 years old living in rural areas. Among them, 30 suffer from chronic psychiatric disorders. Cognition was assessed with four neuropsychological tests: the Mini-Mental State Examination, the Digit Symbol Substitution Test, the Free and Cued Selective Reminding test and the Isaacs Set Test. Linear mixed models were used to compare the evolution of cognitive performances in the two groups between baseline and the four-year follow-up.

RESULTS

Despite lower performances at baseline, the pattern of cognitive decline of the psychiatric group is similar to that of the control group.

CONCLUSION

As suggested by this study conducted in rural communities, community-dwelling people suffering from chronic psychiatric disorders should not be considered at greater risk of age-related accelerated cognitive decline than the non-psychiatric older population.

Functional Impairment in Older Adults With Bipolar Disorder

Data describing bipolar disorder in older adults people are scarce, particularly with regard to functional status. This observational, comparative study assessed psychosocial functioning in 33 euthymic older adults with bipolar disorder compared with 30 healthy controls. In addition, we evaluated the association between clinical variables and poor functioning in the patient group. The mean age of the group was 68.70 years. Patients with bipolar disorder experienced poorer psychosocial functioning (19.15 ± 11.36) than healthy controls (5.17 ± 3.72; p = 0.0001), as assessed using the Functioning Assessment Short Test. Significant differences between the groups were found for specific domains of functioning: autonomy, occupational functioning, cognitive functioning, financial issues, and interpersonal relationships (p = 0.0001, respectively). The largest variation was observed in overall functioning (Cohen's d = 0.63). The number of previous hospitalizations was strongly associated with poor overall functioning (F = 7.217, p = 0.002). Older patients with bipolar disorder had a greater functional impairment than the healthy control group. Implementation of novel rehabilitation models is critical to help patients manage their illness.

Cognitive flexibility: A trait of bipolar disorder that worsens with length of illness

INTRODUCTION

Deficits in cognitive flexibility, a difficulty altering thoughts and behavioral responses in a changing environment, are found in individuals with bipolar disorder (BD) and are associated with poor social and work functioning. However, the current literature is inconsistent in clarifying the long-term nature of these deficits for those with BD. We administered a common task of cognitive flexibility, the Wisconsin Card Sorting Task (WCST) and accounted for demographics, clinical, and cognitive features of BD, to determine the state versus trait characteristics of these deficits.

METHOD

The Wisconsin Card Sorting Test (WCST) was administered to 154 adults with BD and 95 healthy controls twice, one year apart.

RESULTS

The main findings show that cognitive inflexibility is a trait feature of BD, independent of clinical features, that may modestly worsen over time due to the presence of certain demographic, cognitive, and functional features of the disorder. In addition, improvements in WCST performance over an extended period of time in both those with and those without already existing cognitive flexibility deficits indicate potential practice effects.

CONCLUSIONS

These findings suggest that the implementation of early interventions before the illness progresses could potentially prevent further cognitive impairment, mitigate functional outcomes, and improve the quality of life of the individual with BD.

Influence of cognitive reserve on neuropsychological functioning in bipolar disorder: Findings from a 5-year longitudinal study

OBJECTIVES

The present study examined the 5-year longitudinal course of cognitive functioning in a large sample of well-characterized patients with bipolar disorder (BP), compared to healthy controls (HCs), and the influence of cognitive reserve factors (e.g., education and IQ) on cognitive change over time.

METHODS

Participants included 159 individuals diagnosed with BP and 54 HCs recruited as part of a longitudinal naturalistic study of BP who had completed neuropsychological testing at the time of their enrollment and again 5 years later.

RESULTS

The overall relative rate of change did not differ between the BP and HC groups. In total, 46.5% of the BP group and 37% of the HC group showed evidence of decline on at least one measure over time. T-test analyses did not find differences between BP 'decliners' and 'non-decliners' in cognitive reserve variables. However, we found that higher baseline intellectual ability was associated with more stability in cognitive test scores over time for the BP group. Results of linear regression modeling revealed that lower verbal IQ and education were related to increased cognitive decline in specific domains in the BP group.

CONCLUSIONS

This study has explored the influence of cognitive reserve on preservation of specific cognitive abilities over time in BP. The BP group did not demonstrate accelerated cognitive decline over 5 years compared to the HC group. Although the trajectory of cognitive change over time was similar between BP patients and HCs, higher overall intellectual ability may be a protective factor against cognitive decline, particularly for BP patients.

Validity of a common quality of life measurement in homeless individuals with bipolar disorder and schizophrenia

OBJECTIVE

To provide new evidence regarding the validity, reliability, sensitivity to change and acceptability of a schizophrenia (SCZ) quality of life measurement (S-QoL 18) in homeless people with bipolar disorder (BPD).

METHODS

This multi-centre prospective study was conducted in the following 4 French cities: Lille, Marseille, Paris and Toulouse. In addition to the S-QoL 18, data on sociodemographic information, disease severity using the Modified Colorado Symptom Index (MCSI), recovery using the Recovery Assessment Scale (RAS) and QoL using the Short-Form Health Survey (SF-36) were collected. The S-QoL 18 was tested for construct validity, reliability, external validity, sensitivity to change and acceptability.

RESULTS

In total, 216 homeless patients with BPD participated in this study. The eight-factor structure of the S-QoL 18 was confirmed by confirmatory factor analysis (RMSEA=0.058, CFI=0.98, TLI=0.966). The scalability was satisfactory, with INFIT statistics within an acceptable range (from 0.77 to 1.20). The internal consistency (from 0.43 to 0.76) and reliability coefficients (Cronbach's alpha from 0.65 to 0.86) were satisfactory for all dimensions. The external validity testing revealed that the S-QoL 18 dimension scores were significantly correlated with the MCSI, the RAS and the SF-36 scores. The percentage of missing data for the dimensions (<15%) and sensitivity to change were satisfactory.

CONCLUSIONS

These results demonstrate adequate acceptability and psychometric properties of the S-QoL 18 among homeless patients with BPD. The S-QoL 18 can be a common instrument for measuring QoL in homeless people with SCZ and BD.

Similar Trajectory of Executive Functioning Performance over 5 years among individuals with Bipolar Disorder and Unaffected Controls using Latent Growth Modeling

OBJECTIVE

Executive Functioning (EF) deficits in bipolar disorder (BD) are commonly present regardless of mood state and therefore are considered core features of the illness. However, very little is known about the temporal stability of these deficits. We examined the natural course of EF over a five year period in BD and healthy control (HC) samples.

METHOD

Using a 5-year longitudinal cohort, 91 individuals with BD and 17 HC were administered a battery of neuropsychological tests that captured four main areas of EF: Processing Speed with Interference Resolution, Verbal Fluency with Processing Speed, Inhibitory Control, and Conceptual Reasoning and Set Shifting. Evaluations occurred at study entry, one, and five years later.

RESULTS

Latent Growth Curve Modeling demonstrated that the BD group performed significantly worse in all EF areas than the HC group. Changes in EF from baseline to 5-year follow-up were similar across both diagnostic groups. Older age at baseline, above and beyond education and diagnosis, was associated with worse initial performance in EF. Being of older age was associated with greater decline in Processing Speed with Interference Resolution, and Verbal Fluency with Processing Speed. Higher education was marginally associated with a smaller declining slope for Processing Speed with Interference Resolution.

CONCLUSIONS

Executive functioning deficits in BD persist over time, and in the context of normative age-related decline, may place individuals at greater risk for cognitive disability as the disease progresses. Age and having a BD diagnosis together, however, do not accelerate executive functioning decline over time.

The double burden of age and major depressive disorder on the cognitive control network

Poor cognitive control (CC) is common among older individuals with major depressive disorder (OMDD). At the same time, studies of CC in OMDD with fMRI are relatively limited and often have small samples. The present study was conducted to further examine poor CC in OMDD with early onset depression, as well as to investigate the interactive effects of MDD and aging on cognitive control. Twenty OMDD, 17 older never-depressed comparisons (ONDC), 16 younger adults with MDD (YMDD), and 18 younger never-depressed comparisons (YNDC) participated. All participants completed the Go level of the Parametric Go/No-Go Test, which requires sustained attention and inhibitory control while undergoing functional MRI (fMRI). YNDC were faster in reaction times (RTs) to go targets relative to the other 3 groups, and the YMDD group was faster than the OMDD group. fMRI effects of both age and diagnosis were present, with greater activation in MDD, and in aging. Additionally, the interaction of age and MDD was also significant, such that OMDD exhibited greater recruitment of fronto-subcortical regions relative to older comparisons. These results are consistent with prior research reporting that OMDD recruit more fronto-striatal regions in order to perform at the same level as their never-depressed peers, here on a task of sustained attention and inhibitory control. There may be an interaction of cognitive aging and depression to create a double burden on the CC network in OMDD, including possible fronto-striatal compensation during CC that is unique to OMDD, as younger MDD individuals do not show this pattern.

Decreased Fronto-Limbic Activation and Disrupted Semantic-Cued List Learning in Major Depressive Disorder

OBJECTIVES

Individuals with major depressive disorder (MDD) demonstrate poorer learning and memory skills relative to never-depressed comparisons (NDC). Previous studies report decreased volume and disrupted function of frontal lobes and hippocampi in MDD during memory challenge. However, it has been difficult to dissociate contributions of short-term memory and executive functioning to memory difficulties from those that might be attributable to long-term memory deficits.

METHODS

Adult males (MDD, n=19; NDC, n=22) and females (MDD, n=23; NDC, n=19) performed the Semantic List Learning Task (SLLT) during functional magnetic resonance imaging. The SLLT Encoding condition consists of 15 lists, each containing 14 words. After each list, a Distractor condition occurs, followed by cued Silent Rehearsal instructions. Post-scan recall and recognition were collected. Groups were compared using block (Encoding-Silent Rehearsal) and event-related (Words Recalled) models.

RESULTS

MDD displayed lower recall relative to NDC. NDC displayed greater activation in several temporal, frontal, and parietal regions, for both Encoding-Silent Rehearsal and the Words Recalled analyses. Groups also differed in activation patterns in regions of the Papez circuit in planned analyses. The majority of activation differences were not related to performance, presence of medications, presence of comorbid anxiety disorder, or decreased gray matter volume in MDD.

CONCLUSIONS

Adults with MDD exhibit memory difficulties during a task designed to reduce the contribution of individual variability from short-term memory and executive functioning processes, parallel with decreased activation in memory and executive functioning circuits. Ecologically valid long-term memory tasks are imperative for uncovering neural correlates of memory performance deficits in adults with MDD.

Multivariate pattern analysis strategies in detection of remitted major depressive disorder using resting state functional connectivity

Understanding abnormal resting-state functional connectivity of distributed brain networks may aid in probing and targeting mechanisms involved in major depressive disorder (MDD). To date, few studies have used resting state functional magnetic resonance imaging (rs-fMRI) to attempt to discriminate individuals with MDD from individuals without MDD, and to our knowledge no investigations have examined a remitted (r) population. In this study, we examined the efficiency of support vector machine (SVM) classifier to successfully discriminate rMDD individuals from healthy controls (HCs) in a narrow early-adult age range. We empirically evaluated four feature selection methods including multivariate Least Absolute Shrinkage and Selection Operator (LASSO) and Elastic Net feature selection algorithms. Our results showed that SVM classification with Elastic Net feature selection achieved the highest classification accuracy of 76.1% (sensitivity of 81.5% and specificity of 68.9%) by leave-one-out cross-validation across subjects from a dataset consisting of 38 rMDD individuals and 29 healthy controls. The highest discriminating functional connections were between the left amygdala, left posterior cingulate cortex, bilateral dorso-lateral prefrontal cortex, and right ventral striatum. These appear to be key nodes in the etiopathophysiology of MDD, within and between default mode, salience and cognitive control networks. This technique demonstrates early promise for using rs-fMRI connectivity as a putative neurobiological marker capable of distinguishing between individuals with and without rMDD. These methods may be extended to periods of risk prior to illness onset, thereby allowing for earlier diagnosis, prevention, and intervention.

Neurodevelopmental origins of bipolar disorder: iPSC models

Bipolar disorder (BP) is a chronic neuropsychiatric condition characterized by pathological fluctuations in mood from mania to depression. Adoption, twin and family studies have consistently identified a significant hereditary component to BP, yet there is no clear genetic event or consistent neuropathology. BP has been suggested to have a developmental origin, although this hypothesis has been difficult to test since there are no viable neurons or glial cells to analyze, and research has relied largely on postmortem brain, behavioral and imaging studies, or has examined proxy tissues including saliva, olfactory epithelium and blood cells. Neurodevelopmental factors, particularly pathways related to nervous system development, cell migration, extracellular matrix, H3K4 methylation, and calcium signaling have been identified in large gene expression and GWAS studies as altered in BP. Recent advances in stem cell biology, particularly the ability to reprogram adult somatic tissues to a pluripotent state, now make it possible to interrogate these pathways in viable cell models. A number of induced pluripotent stem cell (iPSC) lines from BP patient and healthy control (C) individuals have been derived in several laboratories, and their ability to form cortical neurons examined. Early studies suggest differences in activity, calcium signaling, blocks to neuronal differentiation, and changes in neuronal, and possibly glial, lineage specification. Initial observations suggest that differentiation of BP patient-derived neurons to dorsal telencephalic derivatives may be impaired, possibly due to alterations in WNT, Hedgehog or Nodal pathway signaling. These investigations strongly support a developmental contribution to BP and identify novel pathways, mechanisms and opportunities for improved treatments.

Neuroprogression and Cognitive Functioning in Bipolar Disorder: A Systematic Review

Bipolar disorder (BD) has been associated with impairments in a range of cognitive domains including attention, verbal learning, and mental flexibility. These deficits are increased during the acute phases of the illness and worsen over the course of BD. This review will examine the literature in relation to potential mechanisms associated with cognitive decline in BD. Scopus (all databases), Pubmed, and Ovid Medline were systematically searched with no language or year restrictions, up to January 2015, for human studies that collected cross-sectional and longitudinal cognitive data in adults with BD and matched healthy controls (HC). Selected search terms were "bipolar," "cognitive," "aging," "illness duration," "onset," and "progression." Thirty-nine studies satisfied the criteria for consideration. There is evidence that cognitive function in BD is negatively associated with features of illness progression such as number of mood episodes, illness duration, and hospitalizations. Aging does not appear to affect cognitive functioning to a greater extent than in HC. Furthermore, the small number of longitudinal studies in this field does not allow to reaching firm conclusion in terms of which sub-populations would be more prone to cognitive decline in BD. The decline in cognitive abilities over the course of the BD seems to be associated with the number of episodes and number of hospitalizations. No meaningful interaction of age and bipolar disorder has been found in terms of cognitive decline. Future large-scale longitudinal studies are necessary to confirm these findings and assist in the development of preventive interventions in vulnerable individuals.