Apathy and cognitive performance in older adults with depression

Effectiveness of single-session therapy for adult common mental disorders: a systematic review

BACKGROUND

Common mental disorders (CMDs) impose significant socioeconomic impacts on the global community. Nevertheless, over 50% of individuals with CMDs do not receive proper treatment, indicating that the current treatment modalities do not adequately tackle this issue. Since single-session therapy (SST) is a potential method for reducing the treatment gap, it is crucial to evaluate its effectiveness. Therefore, this systematic review aimed to evaluate the effectiveness of SST on CMD symptoms in adults.

METHODS

This systematic review included randomised and non-randomised studies assessing the clinical effectiveness of SST on CMD symptoms in adults. English-written, peer-reviewed studies or dissertations were included, while grey literature was excluded. MEDLINE, Embase, PsycINFO, and Cochrane's CENTRAL were searched on December 13, 2022, from their inception dates. The risk of bias in the included studies was evaluated using RoB 2 and ROBINS-I. A narrative synthesis was performed. This systematic review was registered in the PROSPERO database on July 6, 2022 (CRD42022343925).

RESULTS

Six randomised and three non-randomised studies were included after screening 2,130 records. Three non-randomised studies with a "critical" or "serious" risk of bias were excluded from the synthesis. Therefore, six randomised trials involving 298 participants were included in the synthesis. Four out of six studies had a "high" risk of bias. The participants had non-severe symptoms at baseline, and three intervention types (behavioural activation, DBT, and solution-focused psychotherapy) were evaluated. Five of six studies showed positive results for depression, with only one reporting a positive result for anxiety.

CONCLUSIONS

SST may be effective in improving CMD symptoms in adults, particularly depression. However, there is a limit to deriving definite conclusions due to a high risk of bias in included studies, insufficient sample size and research volume. Further research exploring the characteristics of clients who can benefit from SST is required to facilitate its widespread use.

Cognitive, Disability, and Treatment Outcome Implications of Symptom-Based Phenotyping in Late-Life Depression

OBJECTIVE

Late-life depression is associated with substantial heterogeneity in clinical presentation, disability, and response to antidepressant treatment. We examined whether self-report of severity of common symptoms, including anhedonia, apathy, rumination, worry, insomnia, and fatigue were associated with differences in presentation and response to treatment. We also examined whether these symptoms improved during treatment with escitalopram.

DESIGN

Eighty-nine older adults completed baseline assessments, neuropsychological testing and providing self-reported symptom and disability scales. They then entered an 8-week, placebo-controlled randomized trial of escitalopram, and self-report scales were repeated at the trial's end. Raw symptom scale scores were combined into three standardized symptom phenotypes and models examined how symptom phenotype severity was associated with baseline measures and depression improvement over the trial.

RESULTS

While rumination/worry appeared independent, severity of apathy/anhedonia and fatigue/insomnia were associated with one another and with greater self-reported disability. Greater fatigue/insomnia was also associated with slower processing speed, while rumination/worry was associated with poorer episodic memory. No symptom phenotype severity score predicted a poorer overall response to escitalopram. In secondary analyses, escitalopram did not improve most phenotypic symptoms more than placebo, aside for greater reductions in worry and total rumination severity.

CONCLUSION

Deeper symptom phenotype characterization may highlight differences in the clinical presentation of late-life depression. However, when compared to placebo, escitalopram did not improve many of the symptoms assessed. Further work is needed to determine whether symptom phenotypes inform longer-term course of illness, and which treatments may best benefit specific symptoms.

The Role of Apathy in Spontaneous Verbal and Nonverbal Behaviors: A Transdiagnostic Pilot Study in Neurodegeneration

BACKGROUND

Apathy, characterized by a quantifiable reduction in motivation or goal-directed behavior, is a multidimensional syndrome that has been observed across many neurodegenerative diseases.

OBJECTIVE

To develop a novel task measuring spontaneous action initiation (ie, a nonverbal equivalent to spontaneous speech tasks) and to investigate the association between apathy and executive functions such as the voluntary initiation of speech and actions and energization (ie, ability to initiate and sustain a response).

METHOD

We compared the energization and executive functioning performance of 10 individuals with neurodegenerative disease and clinically significant apathy with that of age-matched healthy controls (HC). We also investigated the association between self-reported scores on the Apathy Evaluation Scale (AES) and performance on energization tasks.

RESULTS

The individuals with apathy made significantly fewer task-related actions than the HC on the novel spontaneous action task, and their scores on the AES were negatively correlated with spontaneous task-related actions, providing preliminary evidence for the task's construct validity. In addition, the individuals with apathy performed more poorly than the HC on all of the energization tasks, regardless of task type or stimulus modality, suggesting difficulty in sustaining voluntary responding over time. Most of the tasks also correlated negatively with the AES score. However, the individuals with apathy also performed more poorly on some of the executive function tasks, particularly those involving self-monitoring.

CONCLUSION

Our work presents a novel experimental task for measuring spontaneous action initiation-a key symptom of apathy-and suggests a possible contribution of apathy to neuropsychological deficits such as poor energization.

An analytical pathway of consumption expenditure with neighborhood deprivation and depression on cognitive health among elderly in India: A moderated mediation approach

BACKGROUND

This study aims to find the linkage between neighborhood deprivation and cognition with depression as a mediating factor while economic condition as a moderator.

METHODS

We have used the recent baseline wave-1 data of Longitudinal Aging Study in India (LASI), 2017-2018. The study was restricted to 60 and above population, consisting of males (14,931) and females (16,533). We have used moderated mediating model to understand the relationship between deprivation (X), cognition (Y) mediated through depression (M), moderated by economic condition (W), while controlling all possible confounders.

RESULTS

Neighborhood deprivation was positively associated with depression (β: 0.12; SE: 0.01) and inversely linked to cognition (β: -0.4; SE: 0.02). Deprivation had a strong indirect effect on cognition that was mediated by depression. Further, interaction of depression (M) and economic condition (W) was negatively associated (β = -0.03; SE: 0.01) with cognition (Y), indicating that lower economic section being more depressed with lower cognitive function.

LIMITATIONS

The study failed to capture other mental health aspects like stress and anxiety using the Depression, Anxiety and Stress Scale-21 items (DASS-21).

CONCLUSIONS

This study has found a link between higher economic condition with low deprivation and depression. Older individuals with better financial situation have improved cognitive level than their counterparts, who are also depressed. This study provides an opportunity to conduct future research on cognitive health in the face of population aging in India.

Executive failure hypothesis explains the trait-level association between motivation and mind wandering

Mind wandering (MW) is commonly observable in daily life. Early studies established an association between motivation and MW at the trait level using a questionnaire survey. Considering that the mechanism of state-level association between them is known, this study was conducted to replicate the trait-level association and determine its possible mechanisms. Two independent samples were analysed using several questionnaires, which included motivation and MW. General one- and multi-dimensional scales were administered for both variables. Besides the successful replication of the significant association between motivation and MW at the trait level, we found that people with low levels of executive function experience high rates of spontaneous MW. This finding indicates that the underlying mechanism of trait-level association is the executive failure hypothesis, which postulates that a failure of executive control during task-related objectives evokes MW. Further, the motivation–MW relationship exhibits a different psychological basis at the state and trait levels.

Dynamics of cognitive action control in late-life depression during action selection

INTRODUCTION

Late-Life Depression (LLD) is characterized by deficits in cognitive control. We investigated the effect of LLD on a subset of cognitive control functions, the Cognitive Action Control (CAC), distinguishing on-line and adaptive control.

METHODS

We compared LLD subjects (n = 31) and Healthy Controls (HC, n = 31) on their performance in a Simon task. The online congruency effect and adaptive effect were compared for reaction times (RT) and accuracy rates between the groups using mixed models. We applied distributional analyses of RT to differentiate the strength of impulsive action selection and the proficiency of selective action suppression. Finally, we measured correlations between the performances on the task and clinical scores of the LLD group.

RESULTS

LLD had increased error rates in congruent trials compared to HC. Conversely, the adaptive CAC was equivalent between the groups. Distributional analyses showed that the fastest actions were less led by pertinent information in LLD. This phenomenon was found exclusively for congruent trials preceded by non-congruent trials. On the other hand, LLD patients, when they take time, were better than HC to suppress selectively non-relevant information. No difference was observed for adaptation to the preceding condition. No association between behavioral measurements and clinical scores were found.

CONCLUSION

Our results suggest that LLD participants have a specific cognitive disturbance of CAC, showing less facilitation than HC in congruent situations. We propose that this originates in a difficulty in LLD patients in disengaging their attention from conflict situations, which is consistent with a biased CAC to aversive stimuli in depression.

The impact of apathy on cognitive performance in the elderly

OBJECTIVES

To examine the impact of apathy on cognitive performance in the elderly following the conceptual principles proposed by Marin1 and Stuss et al2 and to determine the role of the symptoms of apathy in different cognitive domains.

METHODS

Cross-sectional study with a cohort of healthy elderly subjects over 55 years old (n = 140). One hundred forty healthy-elderly subjects (aged 79.24 ± 8.6 years old) were recruited from 12 day centers in Northern Spain. Participants underwent a neuropsychological battery, which evaluated Mini Mental State Examination (MMSE), attention, processing speed, verbal fluency, visual and verbal memory, working memory, and executive functioning. Apathy was assessed by the Lille Apathy Rating Scale (LARS), which is composed of four factors: intellectual curiosity, emotion, action initiation, and self-awareness. Correlation and linear regression analyses were performed.

RESULTS

In the correlational analysis, the LARS total score correlated negatively with global cognition, verbal fluency, and visual and verbal memory. The intellectual curiosity factor correlated negatively with all cognitive domains except attention. The emotion factor correlated negatively with visual memory. No correlation was found between the action initiation and self-awareness factors or any of the cognitive variables. Multiple stepwise regression analysis showed that symptoms of apathy explained cognitive performance in attention, processing speed, verbal fluency, visual and verbal memory, working memory, executive functioning, and MMSE.

CONCLUSIONS

Apathy was significantly associated with cognitive performance, especially with the intellectual curiosity factor. Our results suggest that specific symptoms of apathy contribute differently to individual cognitive domains.

Apathy: a neurocircuitry model based on frontotemporal dementia

Apathy is a symptom shared among many neurological and psychiatric disorders. However, the underlying neurocircuitry remains incompletely understood. Apathy is one of the core features of behavioural variant frontotemporal dementia (bvFTD), a neurodegenerative disease presenting with heterogeneous combinations of socioaffective symptoms and executive dysfunction. We reviewed all neuroimaging studies of apathy in frontotemporal dementia (FTD) attempting to refine a neurocircuitry model and inform clinical definitions. Levels of apathy have been consistently shown to correlate with the severity of executive dysfunctions across a wide range of diseases, including FTD. Some authors view 'energisation'-the loss of which is central in apathy-as a core executive function. Apathy in FTD is most robustly associated with atrophy, hypometabolism and/or hypoperfusion in the dorsolateral prefrontal cortex, the anterior and middle cingulate cortex, the orbitofrontal cortex and the medial and ventromedial superior frontal gyri. Data also suggest that abnormalities in connecting white matter pathways and functionally connected more posterior cortical areas could contribute to apathy. There is a lack of consistency across studies due to small samples, lenient statistical thresholds, variable measurement scales and the focus on apathy as a unitary concept. Integrating findings across studies, we revise a neurocircuitry model of apathy divided along three subcomponents (cognition/planning, initiation, emotional-affective/motivation) with specific neuroanatomical and cognitive substrates. To increase consistency in clinical practice, a recommendation is made to modify the bvFTD diagnostic criteria of apathy/inertia. More generally, we argue that bvFTD constitutes a disease model to study the neurocircuitry of complex behaviours as a 'lesion-based' approach to neuropsychiatric symptoms observed across diagnostic categories.

Symptoms of Apathy Independently Predict Incident Frailty and Disability in Community-Dwelling Older Adults

OBJECTIVE

Although depressive symptoms are widely recognized as a predictor of functional decline among older adults, little is known about the predictive utility of apathy in this population. We prospectively examined apathy symptoms as predictors of incident slow gait, frailty, and disability among non-demented, community-dwelling older adults.

METHODS

We examined 2 independent prospective cohort studies-the LonGenity study (N = 625, 53% women, mean age = 75.2 years) and the Central Control of Mobility in Aging (CCMA) study (N = 312, 57% women, mean age = 76.4 years). Individuals were recruited from 2008 to 2014. Apathy was assessed using 3 items from the Geriatric Depression Scale. Slow gait was defined as 1 standard deviation or more below age- and sex-adjusted mean values, frailty was defined using the Cardiovascular Health Study criteria, and disability was assessed with a well-validated disability scale.

RESULTS

The prevalence of apathy was 20% in the LonGenity cohort and 26% in the CCMA cohort. The presence of apathy at baseline, independent of depressive symptoms (besides apathy), increased the risk of developing incident slow gait (hazard ratio [HR] = 2.10; 95% CI, 1.36-3.24; P = .001), frailty (HR = 2.86; 95% CI, 1.96-4.16; P < .001), and disability (HR = 3.43; 95% CI, 1.73-6.79; P < .001) in the pooled sample. These associations remained significant when accounting for demographics, medical illnesses, and cognitive function.

CONCLUSIONS

Apathy is associated with increased risk of developing slow gait, frailty, and disability, independent of other established risk factors, in non-demented older adults. Apathy should be screened for as a potentially preventable cause of functional decline in clinical psychiatric settings.

The Parkinson's Active Living (PAL) Program

BACKGROUND

Apathy, one of the most common neuropsychiatric symptoms in Parkinson's disease (PD), has been associated with reduced daily functioning, cognition, treatment compliance, quality of life, and increased caregiver burden and distress, among other outcomes.

OBJECTIVES

The purpose of the present study was to develop and gather pilot data on the feasibility, acceptability, and efficacy of the Parkinson's Active Living (PAL) program, to our knowledge, the first behavioral treatment specifically designed to target apathy in patients with PD. The Parkinson's Active Living is a primarily telephone-based, 6-week activity scheduling and monitoring intervention that incorporates external cueing to target disease-related self-generational deficits to reduce levels of apathy in nondemented, highly apathetic patients with PD.

METHODS

Participants aged 44 to 86 years (mean = 66, SD [standard deviation] = 10.7) ranging in disease duration from <1 to 23 years with elevated apathy (Apathy Evaluation Scale >35) were enrolled in a 1-arm trial and tested at 3 time points (baseline, posttest, and 1-month follow-up).

RESULTS

Feasibility aspects (ie, acceptability, demand, implementation, practicality, adaptation, integration, and expansion) and efficacy of PAL program are reported. Matched pairs t tests showed a medium to large effect of treatment on patient apathy (52% showing ≥1 SD improvement), depression (33% showing ≥1 SD improvement), and quality of life at posttest, with improvements in apathy and depression maintained at follow-up.

CONCLUSIONS

The program may hold promise as an effective nonpharmacological intervention for apathy in PD. Implications and future directions are discussed. Randomized controlled trials are needed.

Late-life depression symptom dimensions and cognitive functioning in the Longitudinal Aging Study Amsterdam (LASA)

BACKGROUND

Depression often co-occurs in late-life in the context of declining cognitive functions, but it is not clear whether specific depression symptom dimensions are differentially associated with cognitive abilities.

METHODS

The study sample comprised 3107 community-dwelling older adults from the Longitudinal Aging Study Amsterdam (LASA). We applied a Multiple Indicators Multiple Causes (MIMIC) model to examine the association between cognitive abilities and latent dimensions of the Center for Epidemiologic Studies Depression Scale (CES-D), while accounting for differential item functioning (DIF) due to age, gender and cognitive function levels.

RESULTS

A factor structure consisting of somatic symptoms, positive affect, depressed affect, and interpersonal difficulties fitted the data well. Higher levels of inductive reasoning were significantly associated with lower levels of depressed affect and somatic symptoms, whereas faster processing speed was significantly associated with lower levels of somatic symptoms. DIF due to age and gender was found, but the magnitude of the effects was small and did not alter substantive conclusions.

LIMITATIONS

Due to the cross-sectional context of this investigation, the direction of influence between depression symptom levels and cognitive function levels cannot be established. Furthermore, findings are relevant to non-clinical populations, and they do not clarify whether certain DIF effects may be found only at high or low levels of depression.

CONCLUSIONS

Our findings suggest differential associations between late-life depression dimensions and cognitive abilities in old age, and point towards potential etiological mechanisms that may underline these associations. These findings carry implications for the prognosis of cognitive outcomes in depressed older adults.

Behavior, neuropsychology and fMRI

Cognitive neuroscientists in the late 20th century began the task of identifying the part(s) of the brain concerned with normal behavior as manifest in the psychological capacities as affective powers, reasoning, behaving purposively and the pursuit of goals, following introduction of the 'functional magnetic resonance imaging' (fMRI) method for identifying brain activity. For this research program to be successful two questions require satisfactory answers. First, as the fMRI method can currently only be used on stationary subjects, to what extent can neuropsychological tests applicable to such stationary subjects be correlated with normal behavior. Second, to what extent can correlations between the various neuropsychological tests on the one hand, and sites of brain activity determined with fMRI on the other, be regarded as established. The extent to which these questions have yet received satisfactory answers is reviewed, and suggestions made both for improving correlations of neuropsychological tests with behavior as well as with the results of fMRI-based observations.

A novel strategy for dissecting goal-directed action and arousal components of motivated behavior with a progressive hold-down task

Motivation serves 2 important functions: It guides actions to be goal-directed, and it provides the energy and vigor required to perform the work necessary to meet those goals. Dissociating these 2 processes with existing behavioral assays has been a challenge. In this article, we report a novel experimental strategy to distinguish the 2 processes in mice. First, we characterize a novel motivation assay in which animals must hold down a lever for progressively longer intervals to earn each subsequent reward; we call this the progressive hold-down (PHD) task. We find that performance on the PHD task is sensitive to both food deprivation level and reward value. Next, we use a dose of methamphetamine (METH) 1.0 mg/kg, to evaluate behavior in both the progressive ratio (PR) and PHD tasks. Treatment with METH leads to more persistent lever pressing for food rewards in the PR. In the PHD task, we found that METH increased arousal, which leads to numerous bouts of hyperactive responding but neither increases nor impairs goal-directed action. The results demonstrate that these tools enable a more precise understanding of the underlying processes being altered in manipulations that alter motivated behavior.

The effects of pharmacological modulation of the serotonin 2C receptor on goal-directed behavior in mice

RATIONALE

Impaired goal-directed motivation represents a debilitating class of symptoms common to psychological disorders including schizophrenia and some affective disorders. Despite the known negative impact of impaired motivation, there are currently no effective pharmacological interventions to treat these symptoms.

OBJECTIVES

Here, we evaluate the effectiveness of the serotonin 2C (5-HT2C) receptor selective ligand, SB242084, as a potential pharmacological intervention for enhancing goal-directed motivation in mice. The studies were designed to identify not only efficacy but also the specific motivational processes that were affected by the drug treatment.

METHODS

We tested subjects following treatment with SB242084 (0.75 mg/kg) in several operant lever pressing assays including the following: a progressive ratio (PR) schedule of reinforcement, an effort-based choice task, a progressive hold down task (PHD), and various food intake tests.

RESULTS

Acute SB242084 treatment leads to an increase in instrumental behavior. Using a battery of behavioral tasks, we demonstrate that the major effect of SB242084 is an increase in the amount of responses and duration of effort that subjects will make for food rewards. This enhancement of behavior is not the result of non-specific hyperactivity or arousal nor is it due to changes in food consumption.

CONCLUSIONS

Because of this specificity of action, we suggest that the 5-HT2C receptor warrants further attention as a novel therapeutic target for treating pathological impairments in goal-directed motivation.

The hippocampus and executive functions in depression

BACKGROUND

The relationship between depression, hippocampus (HC), and executive dysfunctions seems complex and has been the focus of research. Recent evidence indicates a possible role of HC in executive dysfunction seen in depression. No such studies on Indian population have been done.

AIM

To look for changes in HC and executive functions in depression.

SETTINGS AND DESIGN

A cross-sectional analytical controlled study. Sample size 50 (controls 50).

MATERIALS AND METHODS

Hippocampal volume and executive dysfunction was measured using structural magnetic resonance imaging (MRI) and Wisconsin Card Sorting Test (WCST), respectively. Findings on these two parameters were compared between depressives and healthy matched controls as well as between first episode (FE) and recurrent depressives and across the severity of depression (mild, moderate, and severe).

STATISTICAL ANALYSIS

Statistical Package for Social Sciences (SPSS) version 17 was used for analysis. Normally distributed continuous variables were analyzed with independent t-tests. Analysis of variance (ANOVA) was used for multiple comparisons. Categorical data were compared with χ(2) or Fisher's exact test. Clinical correlations were conducted using Pearson correlations.

RESULT

Depressed patients had a smaller left (Lt) hippocampal volume as well as poor performance on several measures of executive functions. Smaller hippocampal volume was found even in FE. Those who had a past burden of depressive illness had an even smaller hippocampal volume. No direct correlation was found between the HC volume and cognitive dysfunction.

CONCLUSION

Depressive illness appears to be toxic to the HC. The relationship between HC and executive dysfunction in depression may be indirect through its functional connections.

Apathy: who cares? A concept analysis

Apathy has been identified as an independent clinical syndrome. As prevalent and problematic as it is in the field of neuropsychiatry, there is no fully accepted definition of apathy. In this study, a concept analysis utilizing Rodgers' evolutionary approach was performed. CINAHL Plus with Full Text was searched, and altogether 36 publications were identified for the concept analysis. Our study shows that psychometric scales may have resulted in an inappropriate diagnosis of depression instead of apathy. As a whole, the literature showed that apathy was defined in comparison to depression as well as altered motivation, emotionality, activity, interest, and initiative. We discuss the advances in the development of apathy as an evolutionary concept. Consistent with Rodgers' evolutionary method, these findings are not an endpoint.

The salience network in the apathy of late-life depression

OBJECTIVE

Apathy is prevalent in late-life depression and predicts poor response to antidepressants, chronicity of depression, disability, and greater burden to caregivers. However, little is known about its neurobiology. Salience processing provides motivational context to stimuli. The aim of this study was to examine the salience network (SN) resting-state functional connectivity (rsFC) pattern in elderly depressed subjects with and without apathy.

METHODS

Resting-state functional MRI data were collected from 16 non-demented, non-MCI, elderly depressed subjects and 10 normal elderly subjects who were psychotropic-free for at least 2 weeks. The depressed group included 7 elderly, depressed subjects with high comorbid apathy and 9 with low apathy. We analyzed the rsFC patterns of the right anterior insular cortex (rAI), a primary node of the SN.

RESULTS

Relative to non-apathetic depressed elderly, depressed elderly subjects with high apathy had decreased rsFC of the rAI to dorsal anterior cingulate and to subcortical/limbic components of the SN. Depressed elderly subjects with high apathy also exhibited increased rsFC of the rAI to right dorsolateral prefrontal cortex and right posterior cingulate cortex when compared to non-apathetic depressed elderly.

CONCLUSIONS

Elderly depressed subjects with high apathy display decreased intrinsic rsFC of the SN and an altered pattern of SN rsFC to the right DLPFC node of the central executive network when compared to elderly non-apathetic depressed and normal, elderly subjects. These results suggest a unique biological signature of the apathy of late-life depression and may implicate a role for the rAI and SN in motivated behavior.

Neuroanatomical correlates of apathy in late-life depression and antidepressant treatment response

BACKGROUND

Apathy is a prominent feature of geriatric depression that predicts poor clinical outcomes and hinders depression treatment. Yet little is known about the neurobiology and treatment of apathy in late-life depression. This study examined apathy prevalence in a clinical sample of depressed elderly, response of apathy to selective serotonin reuptake inhibitor (SSRI) treatment, and neuroanatomical correlates that distinguished responders from non-responders and healthy controls.

METHODS

Participants included 45 non-demented, elderly with major depression and 43 elderly comparison individuals. After a 2-week single-blind placebo period, depressed participants received escitalopram 10mg daily for 12 weeks. The Apathy Evaluation Scale (AES) and 24-item Hamilton Depression Rating Scale (HDRS) were administered at baseline and 12 weeks. MRI scans were acquired at baseline for concurrent structural and diffusion tensor imaging of anterior cingulate gray matter and associated white matter tracts.

RESULTS

35.5% of depressed patients suffered from apathy. This declined to 15.6% (p<0.1) following treatment, but 43% of initial sufferers continued to report significant apathy. Improvement of apathy with SSRI was independent of change in depression but correlated with larger left posterior subgenual cingulate volumes and greater fractional anisotropy of left uncinate fasciculi.

LIMITATIONS

Modest sample size, no placebo control, post-hoc secondary analysis, use of 1.5T MRI scanner

CONCLUSIONS

While prevalent in geriatric depression, apathy is separable from depression with regards to medication response. Structural abnormalities of the posterior subgenual cingulate and uncinate fasciculus may perpetuate apathetic states by interfering with prefrontal cortical recruitment of limbic activity essential to motivated behavior.

Heterogeneity of late-life depression: relationship with cognitive functioning

BACKGROUND

Late-life depression is a heterogeneous disorder, whereby cognitive impairments are often observed. This study examines which clinical characteristics and symptom dimensions of late-life depression are especially impacting on specific cognitive domains.

METHODS

Cross-sectional data of 378 depressed and 132 non-depressed older adults between 60-93 years, from the Netherlands Study of Depression in Older adults (NESDO) were used. Depressed older adults were recruited from both inpatient and outpatient mental healthcare institutes and general practices, and diagnosed according to DSM-IV-TR criteria. Multivariable associations were examined with depression characteristics (severity, onset, comorbidity, psychotropic medication) and symptom dimensions as independent variables and cognitive domains (episodic memory, processing speed, interference control, working memory) as dependent variables.

RESULTS

Late-life depression was associated with poorer cognitive functioning. Within depressed participants, higher severity of psychopathology and having a first depressive episode was associated with poorer cognitive functioning. The use of tricyclic antidepressants, serotonergic and noradrenergic working antidepressants, and benzodiazepines was associated with worse cognitive functioning. Higher scores on the mood dimension were associated with poorer working memory and processing speed, whereas higher scores on a motivational and apathy dimension were associated with poorer episodic memory and processing speed.

CONCLUSIONS

Heterogeneity in late-life depression may lead to differences in cognitive functioning. Higher severity and having a first depressive episode was associated with worse cognitive performance. Additionally, different domains of cognitive functioning were associated with specific symptom dimensions. Our findings on the use of psychotropic medication suggest that close monitoring on cognitive side effects is needed.

The independent contributions of cognitive impairment and neuropsychiatric symptoms to everyday function in older adults

The everyday functional capacities of older adults are determined by multiple factors. The primary goal of the present study was to evaluate whether apathy and depression have unique influences on degree of functional impairment, independent of the effects of specific cognitive impairments. Participants included 344 older adults (199 normal, 87 with MCI, 58 with dementia). The Everyday Cognition (ECog) scales were used to measure both global and domain-specific functional abilities. Neuropsychiatric symptoms of depression and apathy were measured by the Neuropsychiatric Inventory (NPI), and specific neuropsychological domains measured included episodic memory and executive functioning. Results indicated that worse memory and executive function, as well as greater depression and apathy, were all independent and additive determinants of poorer functional abilities. Apathy had a slightly more restricted effect than the other variables across the specific functional domains assessed. Secondary analysis suggested that neuropsychiatric symptoms may be more strongly associated with everyday function within cognitively normal and MCI groups, while cognitive impairment is more strongly associated with everyday function in dementia. Thus, a somewhat different set of factors may be associated with functional status across various clinical groups.

Exploring social cognition in patients with apathy following acquired brain damage

Background

Research on cognition in apathy has largely focused on executive functions. To the best of our knowledge, no studies have investigated the relationship between apathy symptoms and processes involved in social cognition. Apathy symptoms include attenuated emotional behaviour, low social engagement and social withdrawal, all of which may be linked to underlying socio-cognitive deficits.

Methods

We compared patients with brain damage who also had apathy symptoms against similar patients with brain damage but without apathy symptoms. Both patient groups were also compared against normal controls on key socio-cognitive measures involving moral reasoning, social awareness related to making judgements between normative and non-normative behaviour, Theory of Mind processing, and the perception of facial expressions of emotion. We also controlled for the likely effects of executive deficits and depressive symptoms on these comparisons.

Results

Our results indicated that patients with apathy were distinctively impaired in making moral reasoning decisions and in judging the social appropriateness of behaviour. Deficits in Theory of Mind and perception of facial expressions of emotion did not distinguish patients with apathy from those without apathy.

Conclusion

Our findings point to a possible socio-cognitive profile for apathy symptoms and provide initial insights into how socio-cognitive deficits in patients with apathy may affect social functioning.

Convergence and divergence of neuroanatomic correlates and executive task performance in healthy controls and psychiatric participants

The associations between brain matter volume in the cerebral cortex and set shifting and attentional control as operationalized by the Wisconsin Card Sort Test (WCST) and Condition Three of the Delis-Kaplan version of the Color Word Interference Test (CWIT) were investigated in 15 healthy controls and 16 heterogeneously diagnosed psychiatric patients with self-control problems using voxel based morphometry. Both groups underwent standardized magnetic resonance imaging and neuropsychological assessment. WCST and CWIT variables, and a composite, were regressed across the whole brain. Although CWIT performance levels were the same in both groups, neuroanatomic correlates for the psychiatric participants invoked the left hemisphere language system, but the bilateral dorsal attention system in the healthy controls. On its own, no neuroanatomic correlates were observed for the WCST. But when part of a composite with CWIT, neuroanatomic correlates in the dorsal attention system emerged for the psychiatric participants. Psychometric combinations of manifest executive task variables may best represent higher level latent neuro-cognitive control systems. Factor analytic studies of neuropsychological test performances suggest the constructs being measured are the same across psychiatric and non-diagnosed participants, however, imaging modalities indicate the relevant neural architecture can vary by group.

Measuring life space in older adults with mild-to-moderate Alzheimer's disease using mobile phone GPS

BACKGROUND

As an indicator of physical and cognitive functioning in community-dwelling older adults, there is increasing interest in measuring life space, defined as the geographical area a person covers in daily life. Typically measured through questionnaires, life space can be challenging to assess in amnestic dementia associated with Alzheimer's disease (AD). While global positioning system (GPS) technology has been suggested as a potential solution, there remains a lack of data validating GPS-based methods to measure life space in cognitively impaired populations.

OBJECTIVE

The purpose of the study was to evaluate the construct validity of a GPS system to provide quantitative measurements of global movement for individuals with mild-to-moderate AD.

METHODS

Nineteen community-dwelling older adults with mild-to-moderate AD (Mini-Mental State Examination score 14-28, age 70.7 ± 2.2 years) and 33 controls (CTL; age 74.0 ± 1.2 years) wore a GPS-enabled mobile phone during the day for 3 days. Measures of geographical territory (area, perimeter, mean distance from home, and time away from home) were calculated from the GPS log. Following a log-transformation to produce symmetrical distributions, group differences were tested using two-sample t tests. Construct validity of the GPS measures was tested by examining the correlation between the GPS measures and indicators of physical function [steps/day, gait velocity, and Disability Assessment for Dementia (DAD)] and affective state (Apathy Evaluation Scale and Geriatric Depression Scale). Multivariate regression was performed to evaluate the relative strength of significantly correlated factors.

RESULTS

GPS-derived area (p < 0.01), perimeter (p < 0.01), and mean distance from home (p < 0.05) were smaller in the AD group compared to CTL. The correlation analysis found significant associations of the GPS measures area and perimeter with all measures of physical function (steps/day, DAD, and gait velocity; p < 0.01), symptoms of apathy (p < 0.01), and depression (p < 0.05). Multivariate regression analysis indicated that gait velocity and dependence were the strongest variables associated with GPS measures.

CONCLUSION

This study demonstrated that GPS-derived area and perimeter: (1) distinguished mild-to-moderate AD patients from CTL and (2) were strongly correlated with physical function and affective state. These findings confirm the ability of GPS technology to assess life space behaviour and may be particularly valuable to continuously monitor functional decline associated with neurodegenerative disease, such as AD.

Negative correlation between affective symptoms and prefrontal activation during a verbal fluency task: a near-infrared spectroscopy study

Only a few studies have examined the relationships between affective symptoms, cognitive function (e.g. verbal fluency), quality of life (QOL), and brain activation in a nonclinical population. The aim of the present study was to assess these relationships and examine the underlying cortical mechanisms in a nonclinical population. Fifty-two healthy male volunteers were assessed for depressive symptoms using the Zung Self-Rating Depression Scale (SDS), for apathy using the Apathy Scale, and QOL using the Medical Outcomes Study short-form 36-item questionnaire (SF36). The volunteers also performed a verbal fluency test (VFT) while hemoglobin concentration changes were assessed on the surface of the frontal cortex using 24-channel near-infrared spectroscopy (NIRS). The SDS and Apathy Scale scores showed significant negative correlations with the scores of most of the SF36 subscales. Frontal activation had a significant negative correlation with the SDS scores and the Apathy Scale. These results suggest that the degree of affective symptoms is associated with a lower QOL in a nonclinical population, and that cortical hypoactivation during a VFT measured by NIRS may objectively identify individuals with a high degree of affective symptoms.

Correlates of cognitive impairment in older Vietnamese

OBJECTIVES

This study examined correlates of cognitive functioning and possible cognitive impairment among older adults living in Da Nang, Vietnam and surrounding rural areas.

METHODS

The analytic sample consisted of 489 adults, 55 and older stratified by gender, age, and residence in a rural or urban area. The sample was 46% rural, 44% women, with a mean age of 69.04. Interviews were conducted in individuals' homes by trained interviewers. The dependent variable was a Vietnamese version of the mini mental status examination (MMSE). A multiple linear regression was run with the MMSE continuous scores reflecting cognitive functioning, while a binary logistic regression was conducted with an education-adjusted cut-off score reflecting possible cognitive impairment. Age, gender, education, material hardship, depressive symptoms Center for Epidemiologic Studies - Depression Scale, war injury, head trauma, diabetes, cardiovascular and cerebrovascular disease conditions served as correlates, controlling for marital status and rural/urban residence.

RESULTS

About 33% of the sample scored below the standard cutoff of 23 on the MMSE. However, only 12.9% of the sample would be considered impaired using the education-adjusted cut-off score. Cognitive functioning and possible cognitive impairment as indicated by MMSE scores were significantly associated with being older, completing fewer years of education, and material hardship. Gender, depressive symptoms, and cerebrovascular disease were associated with cognitive functioning, but not cognitive impairment.

CONCLUSION

These results show that social characteristics, physical illness, and mental health are associated with cognitive functioning. The study also raises questions about the need for standardization of screening measures on Vietnamese populations.

Apathy symptoms modulate motivational decision making on the Iowa gambling task

Background

The present study represents an initial attempt to assess the role of apathy in motivated decision making on the Iowa Gambling Task. Clinical descriptions of patients with apathy highlight deficits in the cognitive, emotional and behavioural aspects of goal directed activity, yet standard neurocognitive tests of these measures fail to demonstrate reliable sensitivity to the disorder. Available research suggests the Iowa Gambling Task is a robust test of complex emotional socio-executive processes involved in motivational decision making, which can analogue real-world goal-directed behaviour.

Methods

We ask whether performance on the Iowa Gambling Task can distinguish brain damaged patients with apathy symptoms from 1) brain damaged patients without apathy and 2) neurologically intact controls. Overall, 22 healthy adults and 29 brain damaged patients took part in this study.

Results

Brain damaged patients with apathy were distinctively impaired on the Iowa Gambling Task compared to both non-apathetic brain damaged patients and neurologically intact healthy controls. On the other hand, standard measures for the cognitive control of behaviour failed to show this sensitivity.

Conclusions

Our results demonstrated that the Iowa Gambling Task is sensitive to the presence of apathy symptoms. We discuss these findings in terms of neurocognition deficits in apathy and the related implications for rehabilitation and clinical intervention.

Relationships between behavioral syndromes and cognitive domains in Alzheimer disease: the impact of mood and psychosis

OBJECTIVES

Behavioral disturbances occur in nearly all Alzheimer disease (AD) patients together with an array of cognitive impairments. Prior investigations have failed to demonstrate specific associations between them, suggesting an independent, rather than shared, pathophysiology. The objective of this study was to reexamine this issue using an extensive cognitive battery together with a sensitive neurobehavioral and functional rating scale to correlate behavioral syndromes and cognitive domains across the spectrum of impairment in dementia.

DESIGN

Cross-sectional study of comprehensive cognitive and behavioral ratings in subjects with AD and mild cognitive impairment.

SETTING

Memory disorders research center.

PARTICIPANTS

Fifty subjects with AD and 26 subjects with mild cognitive impairment; and their caregivers.

MEASUREMENTS

Cognitive rating scales administered included the Mini-Mental State Examination; the Modified Mini-Mental State Examination; the Boston Naming Test; the Benton Visual Retention Test; the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychology Assessment; the Controlled Oral Word Test; the Wechsler Memory Scale logical memory I and logical memory II task; the Wechsler Memory Scale-Revised digit span; the Wechsler Adult Intelligence Scale-Revised digit symbol task; and the Clock Drawing Task together with the Clinical Dementia Rating Scale and the Neuropsychiatric Inventory.

RESULTS

Stepwise regression of cognitive domains with symptom domains revealed significant associations of mood with impaired executive function/speed of processing (Δr = 0.22); impaired working memory (Δr = 0.05); impaired visual memory (Δr = 0.07); and worsened Clinical Dementia Rating Scale (Δr = 0.08). Psychosis was significantly associated with impaired working memory (Δr = 0.13).

CONCLUSIONS

Mood symptoms appear to impact diverse cognitive realms and to compromise functional performance. Among neuropsychological indices, the unique relationship between working memory and psychosis suggests a possible common underlying neurobiology.

The Neurocognitive Phenotype of Apathy following Acquired Brain Damage

Apathy is one of the most common neuropsychiatric sequelae of acquired brain damage. The disorder is usually defined in terms of observed deficits in motivation related behavioural, emotional, and cognitive aspects of goal directed activity. Most neuropsychological research on apathy has focused primarily on its associated neurocognitive correlates; particularly those related to executive dysfunction, or its association with other clinical syndromes like depression. Results from these studies have been mixed, probably reflecting the use of different neuropsychiatric samples and assessment tools, or reflecting the differences in the conceptualisation of apathy across studies. In this study we ask whether performance on ‘standard’ executive tests would distinguish brain-damaged patients with apathy symptoms from those without apathy. To potentially strengthen the power of the possible relationships between apathy and executive function we included brain-injured patients with varied aetiologies, and used a much broader range of ‘executive function’ tests than in previous studies. Results indicate that the Tower of Hanoi puzzle is sensitive to apathy symptoms. Patients with apathy symptoms were significantly impaired on the task compared to non-apathetic patients. Performance on the Wisconsin Card Sorting test, the Hayling and Brixton tests, and the Stroop test failed to show this distinction. We discuss these findings and their implications for treatment and rehabilitation.

The relationship between computer experience and computerized cognitive test performance among older adults

OBJECTIVE

This study compared the relationship between computer experience and performance on computerized cognitive tests and a traditional paper-and-pencil cognitive test in a sample of older adults (N = 634).

METHOD

Participants completed computer experience and computer attitudes questionnaires, three computerized cognitive tests (Useful Field of View (UFOV) Test, Road Sign Test, and Stroop task) and a paper-and-pencil cognitive measure (Trail Making Test). Multivariate analysis of covariance was used to examine differences in cognitive performance across the four measures between those with and without computer experience after adjusting for confounding variables.

RESULTS

Although computer experience had a significant main effect across all cognitive measures, the effect sizes were similar. After controlling for computer attitudes, the relationship between computer experience and UFOV was fully attenuated.

DISCUSSION

Findings suggest that computer experience is not uniquely related to performance on computerized cognitive measures compared with paper-and-pencil measures. Because the relationship between computer experience and UFOV was fully attenuated by computer attitudes, this may imply that motivational factors are more influential to UFOV performance than computer experience. Our findings support the hypothesis that computer use is related to cognitive performance, and this relationship is not stronger for computerized cognitive measures. Implications and directions for future research are provided.

Vascular burden and cognitive functioning in depressed older adults

BACKGROUND

Vascular burden is known to contribute to geriatric depression and cognitive impairment. The objective of our study was to evaluate the relationship between vascular burden and pattern of cognitive impairment in older adults with depression.

METHODS

Ninety-four community-dwelling older adults (mean age = 70.8 years; SD = 7.63) diagnosed with major depression were recruited to participate in the tai chi complementary use study aimed to improve antidepressant response to an antidepressant medication. All participants received comprehensive evaluations of depression, apathy, and vascular risk factors, and completed a battery of cognitive measures of memory, cognitive control, verbal fluency, and attention.

RESULTS

The severity of vascular burden was significantly correlated with depression severity and impaired performance on measures of cognitive control (i.e., inhibition/mental flexibility), and attention, but not memory or verbal fluency. Neither the severity of comorbid apathy nor medical illness burden was related to cognitive impairment.

CONCLUSIONS

Vascular burden in older depressed adults contributes to cognitive impairment, particularly in domains of attention and cognitive control. Our findings suggest that aggressive treatment of vascular risk factors may reduce risk for further cognitive decline in depressed older adults.

Poor dissociation of patient-evaluated apathy and depressive symptoms

Apathy has traditionally been conceptualised as part of depression. The appropriateness of this conceptualisation has now been questioned, with the realization that apathy constitutes a distinct neuropsychiatric condition, with separate rehabilitation and patient-care implications to depression. Research on the relationship between apathy and depression has, however, produced mixed results. One reason for this inconsistency may lie behind who does the apathy evaluation. In this study we investigated whether the relationship between apathy and depression would differ when apathy was evaluated by the patients or an informant. A total of 49 brain damaged patients were assessed on self- and informant-rated Apathy Evaluation Scales. The relationship between the apathy scores and depressive symptoms was then investigated. Patient-rated, and not informant-rated apathy significantly correlated with depression. We discuss the implication of these results on the relationship between the two neuropsychiatric conditions and also in relation to the utility of patient self-evaluations in apathy.

Deterministic learning and attempted suicide among older depressed individuals: cognitive assessment using the Wisconsin Card Sorting Task

BACKGROUND

Late-life suicide is an under-investigated public health problem. Among the putative vulnerabilities for this complex multifactorial behaviour are deficits in cognitive control, an ability to integrate and prioritize multiple cognitive processes in order to flexibly adapt behaviour and meet situational demands. We investigated cognitive control during rule learning in a complex and changing environment in older individuals with suicide attempts of varying lethality.

METHOD

Ninety-three participants over the age of 60 (30 healthy controls, 29 depressed never suicidal, 20 low-lethality suicide attempters, 14 high-lethality suicide attempters) underwent structured clinical and cognitive assessments. Participants then completed the Wisconsin Card Sorting Test (WCST), a well-studied task of cognitive control during rule learning.

RESULTS

High-lethality attempters demonstrated a pattern of deficits involving poor conceptual reasoning, perseverative errors and total errors. Compared to low-lethality attempters and healthy controls, high-lethality attempters demonstrated poor conceptual reasoning, as well as increased rates of perseverative errors and total errors. Compared to non-suicidal depressed participants, high-lethality attempters also made more conceptual errors.

CONCLUSION

High-lethality suicide attempts among older people are associated with impaired cognitive control during rule learning as detected by the WCST. Our data suggest that impairment in cognitive control during rule learning may represent a vulnerability distinct from the impulsive diathesis, typically manifesting in young, low-lethality attempters. This vulnerability may contribute to the high incidence of serious or, often, fatal suicidal acts in old age.

Depressive symptoms and apathy are associated with psychomotor slowness and frontal activation

Affective symptoms, such as depression and apathy, and cognitive dysfunction, such as psychomotor slowness, are known to have negative impacts on the quality of life (QOL) of patients with mental and physical diseases. However, the relationships among depressive symptoms, apathy, psychomotor slowness, and QOL in a non-clinical population are unclear. The aim of the present study was to assess these relationships and examine the underlying cortical mechanisms in a non-clinical population. Fifty-two healthy male volunteers were assessed for depressive symptoms using the Zung Self-rating Depression Scale (SDS), for apathy measured using the Apathy Scale, and QOL using the Short-Form 36 item questionnaire (SF36). The volunteers also performed the Trail Making Test Part A (TMT-A) while undergoing assessment of hemoglobin concentration changes in the frontal cortical surface using 24-channel near-infrared spectroscopy (NIRS). The scores of the SDS and Apathy Scale showed significant negative correlations with the scores of most of subscales of the SF36. In addition, the SDS score had a significant positive correlation with the time to complete the TMT-A. Further, activation of several frontal cortical areas had a significant positive correlation with the scores of the SDS and Apathy Scale. These results suggest that the degree of depressive symptoms and apathy are associated with a lower QOL in a non-clinical population and that cortical hyperactivation during a psychomotor task measured by NIRS may identify objectively individuals with a high degree of depressive symptoms and apathy.

Differential diagnosis between dementia and psychiatric disorders: Diagnostic criteria and supplementary exams. Recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology

In 2005, the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology published recommendations for the diagnosis of Alzheimer's disease These recommendations were updated following a review of evidence retrieved from national and international studies held on PUBMED, SCIELO and LILACS medical databases. The main aims of this review article are as follows:

1) to present the evidence found on Brazilian (LILACS, SCIELO) and International (MEDLINE) databases from articles published up to May 2011, on the differential diagnosis of these psychiatric disorders and dementia, with special focus on Dementia due to Alzheimer's and vascular dementia, including a review of supplementary exams which may facilitate the diagnostic process; and

2) to propose recommendations for use by clinicians and researchers involved in diagnosing patients with dementia.

Differential diagnosis between dementia and other neuropsychiatric disorders should always include assessments for depression, delirium, and use of psychoactive substances, as well as investigate the use of benzodiazepines, anti-epileptics and pattern of alcohol consumption.

Are gerontological nurses apathetic about apathy in older adults

Despite its serious health consequences, apathy in older adults is often underrecognized by gerontological nurses and other health care professionals. Within this article, we discuss what apathy is and present a review of the literature and research. Two frameworks emerging from the literature search-one regarding rehabilitation and the other illness-are introduced as ways in which apathy may be conceptualized and addressed. Using these frameworks, implications for gerontological nurses are outlined.

Differential effects of deep TMS of the prefrontal cortex on apathy and depression

BACKGROUND

Apathy is one hallmark of major depression (MDD). It is distinguished by lack of emotion, whereas other aspects of depression involve considerable emotional distress. Investigating both apathy and depression may increase the degree of treatment efficacy for both ailments together and apart.

OBJECTIVE

Evaluate the differential effects of deep transcranial magnetic stimulation (DTMS) over the prefrontal cortex (PFC) on apathy and other aspects of depression in patients suffering from a depressive episode.

METHODS

Fifty-four treatment-resistant MDD patients were evaluated with the Hamilton Rating Scale for Depression (HRSD), and then treated with DTMS. Apathy-related items from HRSD (ApHRSD) were compared with the remaining items from HRSD (DepHRSD). Antidepressant medications were withdrawn and active DTMS treatment was administered at 20 Hz, 5 days a week for 4 weeks. Changes in HRSD were recorded. Primary efficacy time point was 1 week after the end of active treatment.

RESULTS

At screening, ApHRSD distribution was unimodal (moderate apathy), with low correlation (r = 0.17) between ApHRSD and DepHRSD. After treatment, a third had remitted apathy, and the correlation between ApHRSD and DepHRSD had dramatically increased (r = 0.83). Severe ApHRSD (≥ 7) at screening correlated with nonremission for both ApHRSD (R(2) = 0.1993, P = .0012) and DepHRSD (R(2) = 0.0860, P = .0334).

CONCLUSIONS

DTMS over the PFC improved both apathy and depression similarly. However, DTMS did not lead to MDD remission if ApHRSD at screening was ≥ 7 of 12. Further investigation using a larger sample will determine whether screening apathy at baseline could be used to predict efficacy of DTMS in MDD patients.

Clinical factors that predict cognitive function in patients with major depression

OBJECTIVES

To compare the performance of depressed patients to healthy control subjects on discrete cognitive domains derived from factor analysis and to examine the factors that may influence the performance of depressed patients on cognitive domains in a large sample.

METHODS

We compared the cognitive performance of 149 patients with major depression to 104 healthy control subjects using multivariate ANCOVA. We used principal component factor analysis to group the cognitive variables into cognitive domains. Finally, we conducted regression analysis to examine the contribution of predictor factors to the cognitive domains that were impaired in the depressed group.

RESULTS

Verbal memory and speed of processing were impaired in depressed patients, compared with healthy control subjects. Patient IQ, duration of depressive illness, and number of hospitalizations significantly contributed to the performance of patients on verbal memory and speed of processing. The severity of mood symptoms did not correlate with performance on any cognitive domain.

CONCLUSIONS

Understanding the factors that predict cognitive performance of patients with depression may provide an insight into the processes by which depression leads to cognitive dysfunction. Our study showed that premorbid IQ and factors related to burden of illness are strong independent predictors of cognitive dysfunction in patients with major depression.

Impaired sustained attention and executive dysfunction: bipolar disorder versus depression-specific markers of affective disorders

OBJECTIVE

To identify neurocognitive measures that could be used as objective markers of bipolar disorder.

METHODS

We examined executive function, sustained attention and short-term memory as neurocognitive domains in 18 participants with bipolar disorder in euthymic state (Beuth), 14 in depressed state (Bdep), 20 with unipolar depression (Udep) and 28 healthy control participants (HC). We conducted four-group comparisons followed by relevant post hoc analyses.

RESULTS

Udep and Bdep, but not Beuth showed impaired executive function (p=0.045 and p=0.046, respectively). Both Bdep and Beuth, but not Udep, showed impaired sustained attention (p=0.001 and p=0.045, respectively). The four groups did not differ significantly on short-term memory. Impaired sustained attention and executive dysfunction were not associated with depression severity, duration of illness and age of illness onset. Only a small number of abnormal neurocognitive measures were associated with medication in Bdep and Beuth.

CONCLUSION

Impaired sustained attention appears specific to bipolar disorder and present in both Beuth and Bdep; it may represent an objective marker of bipolar disorder. Executive dysfunction by contrast, appears to be present in Udep and Bdep and likely represents a marker of depression.