Lewy Bodies, Vascular Risk Factors, and Subcortical Arteriosclerotic Leukoencephalopathy, but not Alzheimer Pathology, are Associated with Development of Psychosis in Alzheimer's Disease

Unraveling the Potential Underlying Mechanisms of Mild Behavioral Impairment: Focusing on Amyloid and Tau Pathology

The emergence of sustained neuropsychiatric symptoms (NPS) among non-demented individuals in later life, defined as mild behavioral impairment (MBI), is linked to a higher risk of cognitive decline. However, the underlying pathophysiological mechanisms remain largely unexplored. A growing body of evidence has shown that MBI is associated with alterations in structural and functional neuroimaging studies, higher genetic predisposition to clinical diagnosis of Alzheimer's disease (AD), as well as amyloid and tau pathology assessed in the blood, cerebrospinal fluid, positron-emission tomography (PET) imaging and neuropathological examination. These findings shed more light on the MBI-related potential neurobiological mechanisms, paving the way for the development of targeted pharmacological approaches. In this review, we aim to discuss the available clinical evidence on the role of amyloid and tau pathology in MBI and the potential underlying pathophysiological mechanisms. Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, disruption of neurotrophic factors, such as the brain-derived neurotrophic factor (BDNF), abnormal neuroinflammatory responses including the kynurenine pathway, dysregulation of transforming growth factor beta (TGF-β1), epigenetic alterations including micro-RNA (miR)-451a and miR-455-3p, synaptic dysfunction, imbalance in neurotransmitters including acetylcholine, dopamine, serotonin, gamma-aminobutyric acid (GABA) and norepinephrine, as well as altered locus coeruleus (LC) integrity are some of the potential mechanisms connecting MBI with amyloid and tau pathology. The elucidation of the underlying neurobiology of MBI would facilitate the design and efficacy of relative clinical trials, especially towards amyloid- or tau-related pathways. In addition, we provide insights for future research into our deeper understanding of its underlying pathophysiology of MBI, and discuss relative therapeutic implications.

Psychosis in Alzheimer's disease is associated with specific changes in brain MRI volume, cognition and neuropathology

Psychosis in Alzheimer's Disease (AD) is prevalent and indicates poor prognosis. However, the neuropathological, cognitive and brain atrophy patterns underlying these symptoms have not been fully elucidated. In this study, we evaluated 178 patients with AD neuropathological change (ADNC) and ante-mortem volumetric brain magnetic resonance imaging (MRI). Presence of psychosis was determined using the Neuropsychiatric Inventory Questionnaire. Clinical Dementia Rating Sum-of-boxes (CDR-SB) was longitudinally compared between groups with a follow-up of 3000 days using mixed-effects multiple linear regression. Neuropsychological tests closest to the time of MRI and brain regional volumes were cross-sectionally compared. Psychosis was associated with lower age of death, higher longitudinal CDR-SB scores, multi-domain cognitive deficits, higher neuritic plaque severity, Braak stage, Lewy Body pathology (LB) and right temporal lobe regional atrophy. Division according to the presence of LB showed differential patterns of AD-typical pathology, cognitive deficits and regional atrophy. In conclusion, psychosis in ADNC with and without LB has clinical value and associates with subgroup patterns of neuropathology, cognition and regional atrophy.

Neuropsychiatric Manifestations in Alzheimer's Disease Patients: Genetics and Treatment Options

BACKGROUND

Alzheimer's disease (AD) is characterized by neuropsychiatric symptoms (NPS), which cause great misery to those with dementia and those who care for them and may lead to early institutionalization.

OBJECTIVE

The present systematic review aims to discuss the various aspects of Alzheimer's, including treatment options.

METHODS

The databases Embase, PubMed, and Web of Science were searched to collect data.

RESULTS

Incipient cognitive deterioration is commonly accompanied by these early warning signals of neurocognitive diseases. The neurobiology of NPSs in Alzheimer's disease, as well as particular symptoms, including psychosis, agitation, apathy, sadness, and sleep disorders, will be examined in this review. For NPSs in Alzheimer's disease, clinical trial designs, as well as regulatory issues, were also addressed. A fresh wave of research, however, is helping to push the discipline ahead. For medication development and repurposing, we highlight the most recent results in genetics, neuroimaging, and neurobiology. Even though identifying and treating psychosis in adults with dementia is still a challenging endeavor, new options are coming up that give the field fresh focus and hope. Conclsuion: It can be concluded from the complete literature survey that Alzheimer's-related psychosis as well as other symptoms that are not psychotic, have made significant progress in the last decade. These milestones in the development of safer, more effective treatments have been achieved as a consequence of great focus on non-pharmacological interventions like DICE or WHELD; the investigation into ways to improve existing drugs like aripiprazole, risperidone, amisulpride, and Escitalopram for safer precision-based treatment; and the development of a clinical trial program for pimavanserin.

Under-Diagnosis of Dementia with Lewy Bodies in Individuals Racialized as Black: Hypotheses Regarding Potential Contributors

Dementia with Lewy bodies (DLB) is one of the most common degenerative dementias after Alzheimer's disease (AD) dementia. DLB is under-diagnosed across populations but may be particularly missed in older Black adults. The object of this review was to examine key features of DLB and potential associations with race in order to hypothesize why DLB may be under-diagnosed in Black adults in the U.S. In terms of dementia, symptoms associated with high rates of co-pathology (e.g., AD, vascular disease) in older Black adults may obscure the clinical picture that might suggest Lewy body pathology. Research also suggests that clinicians may be predisposed to give AD dementia diagnoses to Black adults, potentially missing contributions of Lewy body pathology. Hallucinations in Black adults may be misattributed to AD or primary psychiatric disease rather than Lewy body pathology. Research on the prevalence of REM sleep behavior in diverse populations is lacking, but REM sleep behavior disorder could be under-diagnosed in Black adults due to sleep patterns or reporting by caregivers who are not bed partners. Recognition of parkinsonism could be reduced in Black adults due to clinician biases, cultural effects on self-report, and potentially underlying differences in the frequency of parkinsonism. These considerations are superimposed on structural and systemic contributions to health (e.g., socioeconomic status, education, structural racism) and individual-level social exposures (e.g., social interactions, discrimination). Improving DLB recognition in Black adults will require research to investigate reasons for diagnostic disparities and education to increase identification of core symptoms in this population.

Neurodegenerative pathologies associated with behavioral and psychological symptoms of dementia in a community-based autopsy cohort

In addition to the memory disorders and global cognitive impairment that accompany neurodegenerative diseases, behavioral and psychological symptoms of dementia (BPSD) commonly impair quality of life and complicate clinical management. To investigate clinical-pathological correlations of BPSD, we analyzed data from autopsied participants from the community-based University of Kentucky Alzheimer's Disease Research Center longitudinal cohort (n = 368 research volunteers met inclusion criteria, average age at death 85.4 years). Data assessing BPSD were obtained approximately annually, including parameters for agitation, anxiety, apathy, appetite problems, delusions, depression, disinhibition, hallucinations, motor disturbance, and irritability. Each BPSD was scored on a severity scale (0-3) via the Neuropsychiatric Inventory Questionnaire (NPI-Q). Further, Clinical Dementia Rating (CDR)-Global and -Language evaluations (also scored on 0-3 scales) were used to indicate the degree of global cognitive and language impairment. The NPI-Q and CDR ratings were correlated with neuropathology findings at autopsy: Alzheimer's disease neuropathological changes (ADNC), neocortical and amygdala-only Lewy bodies (LBs), limbic predominant age-related TDP-43 encephalopathy neuropathologic changes (LATE-NC), primary age-related tauopathy (PART), hippocampal sclerosis, and cerebrovascular pathologies. Combinations of pathologies included the quadruple misfolding proteinopathy (QMP) phenotype with co-occurring ADNC, neocortical LBs, and LATE-NC. Statistical models were used to estimate the associations between BPSD subtypes and pathologic patterns. Individuals with severe ADNC (particularly those with Braak NFT stage VI) had more BPSD, and the QMP phenotype was associated with the highest mean number of BPSD symptoms: > 8 different BPSD subtypes per individual. Disinhibition and language problems were common in persons with severe ADNC but were not specific to any pathology. "Pure" LATE-NC was associated with global cognitive impairment, apathy, and motor disturbance, but again, these were not specific associations. In summary, Braak NFT stage VI ADNC was strongly associated with BPSD, but no tested BPSD subtype was a robust indicator of any particular "pure" or mixed pathological combination.

The neural signatures of psychoses in Alzheimer's disease: a neuroimaging genetics approach

Psychoses in Alzheimer's disease (AD) are associated with worse prognosis. Genetic vulnerability for schizophrenia (SCZ) may drive AD-related psychoses, yet its impact on brain constituents is still unknown. This study aimed to investigate the association between polygenic risk scores (PRSs) for SCZ and psychotic experiences (PE) and grey matter (GM) volume in patients with AD with (AD-PS) and without (AD-NP) psychosis. Clinical, genetic and T1-weighted MRI data for 800 participants were extracted from the ADNI database: 203 healthy controls, 121 AD-PS and 476 AD-NP. PRSs were calculated using a Bayesian approach and analysed at ten p-value thresholds. Standard voxel-based morphometry was used to process MRI data. Logistic regression models including both PRSs for SCZ and PE, and an AD-PRS were used to predict psychosis in AD. Associations between PRSs and GM volume were investigated in the whole sample and the three groups independently. Only the AD-PRS predicted psychosis in AD. Inconsistent associations between the SCZ-PRS and PE-PRS and GM volumes were found across groups. The SCZ-PRS was negatively associated with medio-temporal/subcortical volumes and positively with medial/orbitofrontal volumes in the AD-PS group. Only medio-temporal areas were more atrophic in the AD-PS group, while there was no significant correlation between psychosis severity and GM volume. Although not associated with psychoses, the SCZ-PRS was correlated with smaller medio-temporal and larger orbitofrontal volumes in AD-PS. Similar alterations have also been observed in SCZ patients. This finding suggest a possible disconnection between these regions associated with psychoses in more advanced AD.

Accelerated atrophy in dopaminergic targets and medial temporo-parietal regions precedes the onset of delusions in patients with Alzheimer's disease

People with Alzheimer's disease (AD) and delusions have worse quality of life and prognosis. However, early markers of delusions have not been identified yet. The present study investigated whether there are any detectable differences in grey matter (GM) volume and cognitive changes in the year before symptom onset between patients with AD who did and did not develop delusions. Two matched samples of AD patients, 63 who did (PT-D) and 63 who did not develop delusions (PT-ND) over 1 year, were identified from the Alzheimer's Disease Neuroimaging Initiative database. The Neuropsychiatric Inventory (NPI) was used to assess the presence of delusions. Sixty-three additional matched healthy controls (HC) were selected. Repeated-measures ANCOVA models were used to investigate group-by-time effects on the volume of selected GM regions of interest and on cognitive performance. No neurocognitive differences were observed between patient groups prior to symptom onset. Greater episodic memory decline and GM loss in bilateral caudate nuclei, medio-temporal and midline cingulo-parietal regions were found in the PT-D compared with the PT-ND group. A pattern of faster GM loss in brain areas typically affected by AD and in cortical and subcortical targets of dopaminergic pathways, paralleled by worsening of episodic memory and behavioural symptoms, may explain the emergence of delusions in patients with AD.

Mild behavioral impairment is associated with progression to Alzheimer's disease: A clinicopathological study

INTRODUCTION

Mild behavioral impairment (MBI) is characterized by later-life emergence of neuropsychiatric symptoms. Investigating its relationship with progression to Alzheimer's disease (AD) would provide insight on its importance as a predictor of AD.

METHODS

Cognitively normal participants (N = 11,372) from the National Alzheimer's Coordinating Center were stratified by MBI status, using the Neuropsychiatric Inventory-Questionnaire. We investigated whether MBI and its domains were predictors of progression to clinically-diagnosed AD. MBI as a predictor of progression to neuropathology-confirmed AD was also investigated in those with neuropathological data.

RESULTS

Six percent (N = 671) of participants progressed to AD. MBI (N = 2765) was a significant predictor of progression to clinically-diagnosed (hazard ratio [HR] = 1.75) and neuropathology-confirmed AD (HR = 1.59). MBI domains were also associated with clinically-diagnosed AD, with psychosis having the greatest effect (HR = 6.49).

DISCUSSION

These findings support the biological underpinnings of MBI, emphasizing the importance of later life behavioral changes in dementia detection and prognostication.

A Multimodal Neuroimaging and Neuropsychological Study of Visual Hallucinations in Alzheimer’s Disease

Background: Hallucinations in Alzheimer’s disease (AD) have been linked to more severe cognitive and functional decline. However, research on visual hallucinations (VH), the most common type of hallucinations in AD, is limited. Objective: To investigate the cognitive and cerebral macrostructural and metabolic features associated with VH in AD. Methods: Twenty-four AD patients with VH, 24 with no VH (NVH), and 24 cognitively normal (CN) matched controls were selected from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database. Differences in regional gray matter (GM) volumes and cognitive performance were investigated with whole brain voxel-based morphometry analyses of MRI structural brain scans, and analyses of neuropsychological tests. Glucose metabolic changes were explored in a subsample of patients who had FDG-PET scans available. Results: More severe visuoconstructive and attentional deficits were found in AD VH compared with NVH. GM atrophy and hypometabolism were detected in occipital and temporal areas in VH patients in comparison with CN. On the other hand, NVH patients had atrophy and hypometabolism mainly in temporal areas. No differences in GM volume and glucose metabolism were found in the direct comparison between AD VH and NVH. Conclusion: In addition to the pattern of brain abnormalities typical of AD, occipital alterations were observed in patients with VH compared with CN. More severe visuoconstructive and attentional deficits were found in AD VH when directly compared with NVH, and might contribute to the emergence of VH in AD.

Psychosis as a Treatment Target in Dementia: A Roadmap for Designing Interventions

Psychotic phenomena are among the most severe and disruptive symptoms of dementias and appear in 30% to 50% of patients. They are associated with a worse evolution and great suffering to patients and caregivers. Their current treatments obtain limited results and are not free of adverse effects, which are sometimes serious. It is therefore crucial to develop new treatments that can improve this situation. We review available data that could enlighten the future design of clinical trials with psychosis in dementia as main target. Along with an explanation of its prevalence in the common diseases that cause dementia, we present proposals aimed at improving the definition of symptoms and what should be included and excluded in clinical trials. A review of the available information regarding the neurobiological basis of symptoms, in terms of pathology, neuroimaging, and genomics, is provided as a guide towards new therapeutic targets. The correct evaluation of symptoms is transcendental in any therapeutic trial and these aspects are extensively addressed. Finally, a critical overview of existing pharmacological and non-pharmacological treatments is made, revealing the unmet needs, in terms of efficacy and safety. Our work emphasizes the need for better definition and measurement of psychotic symptoms in dementias in order to highlight their differences with symptoms that appear in non-dementing diseases such as schizophrenia. Advances in neurobiology should illuminate the development of new, more effective and safer molecules for which this review can serve as a roadmap in the design of future clinical trials.

Associations Between Neuropsychiatric Symptoms and Neuropathological Diagnoses of Alzheimer Disease and Related Dementias

IMPORTANCE

Understanding associations of Alzheimer disease (AD) and related dementias (ADRD) pathologies with common neuropsychiatric symptoms (NPS) may have implications for diagnosis and management.

OBJECTIVE

To evaluate ADRD neuropathological diagnoses and NPS without consideration of clinical diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study evaluated 1808 brains from 39 sites in the US National Alzheimer Coordinating Center v. 10 collection for participants among whom the Neuropsychiatric Inventory Questionnaire (NPIQ) was administered annually. Brain autopsy diagnoses of AD, Lewy body disease (LBD), cerebral amyloid angiopathy, frontotemporal lobar degeneration, cerebrovascular disease, hippocampal sclerosis, and no known pathology were examined. Autopsy data collected from January 2012 to January 2018 were deidentified and compiled into the publicly available v. 10 database. Data were analyzed from February 2021 to August 2021.

MAIN OUTCOMES AND MEASURES

The primary outcome was NPIQ domain score, if present at any time point, and mean NPIQ domain score during follow-up was secondary. Associations of ADRD diagnoses with 12 NPIQ symptom domains were examined in regression analyses, correcting for multiple comparisons.

RESULTS

The study sample of 1808 adults had a mean (SD) age of 80.0 (11.0) years, and 987 participants (54.6%) were male. Apathy was the most prevalent NPS, reaching 80% (203 of 254 individuals) in those with hippocampal sclerosis. Cerebrovascular disease showed few NPS associations. Frontotemporal lobar degeneration was associated with increased apathy, increased disinhibition, and decreased psychosis and agitation compared with AD. Hippocampal sclerosis was associated with increased apathy (odds ratio, 2.60; 95% CI; 1.86-3.66, false discovery rate controlled P < .001) and disinhibition (odds ratio, 2.15; 95% CI, 1.63-2.84; false discovery rate controlled P < .001). In multiple regression analyses that included concomitant neuropathologies, the main findings remained. More severe pathology was consistently associated with increased NPS (eg, LBD was associated with an increase in hallucinations from brain stem [β, 0.23; 95% CI, 0.07-0.76; P = .02] to limbic [β, 1.69; 95% CI, 1.27-2.27; P < .001] to neocortical [β, 4.49; 95% CI, 3.27-6.16; P < .001] pathology). Hallucinations were more common in participants with AD and LBD (168 of 534 [31.5%]) compared with those with AD without LBD (152 of 704 [21.6%]) and those with LBD without AD (23 of 119 [19.6%]).

CONCLUSIONS AND RELEVANCE

In this cohort study of 1808 brains from the US National Alzheimer Coordinating Center, patients with LBD and AD showed a higher prevalence of hallucinations compared with those with LBD without AD. Neuropsychiatric symptom criteria of apathy and disinhibition in behavioral variant frontotemporal lobar degeneration were supported in this study. In hippocampal sclerosis, the findings of increased apathy and disinhibition merit further investigation. Severity of neuropathology was associated with NPS severity, indicating that NPS may reflect underlying ADRD pathology and highlighting the importance of diagnosing and treating NPS.

Psychosis in Alzheimer disease - mechanisms, genetics and therapeutic opportunities

Psychosis is a common and distressing symptom in people with Alzheimer disease, and few safe and effective treatments are available. However, new approaches to symptom assessment and treatment are beginning to drive the field forward. New nosological perspectives have been provided by incorporating the emergence of psychotic symptoms in older adults - even in advance of dementia - into epidemiological and neurobiological frameworks as well as into diagnostic and research criteria such as the International Psychogeriatric Association criteria for psychosis in neurocognitive disorders, the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART) research criteria for psychosis in neurodegenerative disease, and the ISTAART criteria for mild behavioural impairment. Here, we highlight the latest findings in genomics, neuroimaging and neurobiology that are informing approaches to drug discovery and repurposing. Current pharmacological and non-pharmacological treatment options are discussed, with a focus on safety and precision medicine. We also explore trial data for pimavanserin, a novel agent that shows promise for the treatment of psychosis in people with dementia, and discuss existing agents that might be useful but need further exploration such as escitalopram, lithium, cholinesterase inhibitors and vitamin D. Although the assessment and management of psychosis in people with dementia remain challenging, new opportunities are providing direction and hope to the field.

Neuropsychiatric symptoms and cerebrovascular risk in non-demented elders: cross-sectional study using the mild behavioural impairment checklist (MBI-C)

BACKGROUND

Neuropsychiatric symptoms (NPS) may represent early clinical manifestations of evolving brain diseases. Studies underpin the occurrence of NPS in the context of mild cognitive impairment (MCI) and prodromal Alzheimer's disease, where symptoms referred to as 'mild behavioural impairment' (MBI) have been shown to predict conversion to dementia and to hasten cognitive/functional decline. However, the association between NPS and cerebrovascular risk factors has been poorly investigated, despite the high prevalence of the latter among individuals with MCI. The aim of the present study was to investigate the association between MBI and cerebrovascular risk in a clinical sample of non-demented elders.

METHODS

Sixty-five MCI and 15 cognitively unimpaired older adults were cross-sectionally assessed with the Mild Behavioural Impairment Checklist (MBI-C), using the cut-off score > 6.5 to define positive screening. Participants were submitted to the Hachinski Ischaemic Score (HIS) to account for cerebrovascular symptoms, vascular risk, and related comorbidities. Neuroimaging scans (magnetic resonance imaging and/or 18F-fluorodeoxyglucose-positron emission tomography) and apolipoprotein E genotype were obtained.

RESULTS

Positive associations were found between total MBI-C scores and increasing number of comorbidities present (0-2 comorbidities), but not with three comorbidities. Two domains of the MBI-C-impulse dyscontrol and social inappropriateness-followed the same trend of the MBI-C total score, with higher scores with the increasing numbers of comorbidities. No significant associations were found between MBI symptoms and HIS or cerebrovascular burden in neuroimaging assessment.

CONCLUSION

We found weak associations between MBI-C total score and the presence of comorbidities with cerebrovascular risk, but not with structural or functional neuroimaging abnormalities or HIS. This finding may represent that the presence of comorbidities adds limited risk to the occurrence of MBI in this sample of non-demented elders.

TAR DNA-Binding Protein 43 Is Associated with Rate of Memory, Functional and Global Cognitive Decline in the Decade Prior to Death

Background:

Transactive response DNA-binding protein of 43 kDa (TDP-43) is associated with memory impairment and overall cognitive decline. It is unclear how TDP-43 contributes to the rate of clinical decline.

Objective:

To determine whether cross-sectional and longitudinal cognitive and functional decline are associated with anatomical distribution of TDP-43 in the brain.

Methods:

Longitudinal clinical-neuropathologic autopsy cohort study of 385 initially cognitively normal/mildly impaired older adults prospectively followed until death. We investigated how TDP-43, amyloid-β (Aβ), tau neurofibrillary tangles (NFT), Lewy body disease (LBD), age, sex, and genetics are associated with clinical scores and rates of their longitudinal decline.

Results:

Of 385 participants, 260 (68%) had no TDP-43, 32 (8%) had TDP-43 limited to amygdala, and 93 (24%) had TDP-43 in the hippocampus and beyond. Higher TDP-43 and Braak NFT stages independently were associated with faster decline in global cognition, functional performance measured by Clinical Dementia Rating scale, and naming and episodic memory, whereas older age was associated with slower rate of cognitive, psychiatric, and functional decline. Cross-sectionally the following associations were found: higher TDP-43 and Braak NFT - worse performance; higher Aβ burden - worse global cognition, more behavioral changes, the latter also with higher LBD; older age - worse naming, lower frequency of behavioral changes; female sex - more impaired naming and better preserved episodic memory. There were no genetic associations.

Conclusion:

The association of TDP-43 distribution with decline in cognitive and functional performance suggests that TDP-43 is playing a role in the clinical progression to dementia. Further characterization of clinical features associated with TDP-43 can facilitate establishment of antemortem diagnosis.

Prevalence and Associated Factors of Visual Hallucinations in Patients with Vascular Cognitive Impairment

Visual hallucinations (VHs) are striking features for dementia, especially dementia with Lewy bodies (DLB). We aimed to study the frequency and associated factors of VH in vascular cognitive impairment (VCI) and investigate the feasibility of clinically diagnosing the mixed pathology of VCI with DLB. This is a multicentre registration study. A consecutive series of VCI patients with and without dementia were enrolled. Frequency of VH and associated factors, including age, gender, education, disease severity, DLB clinical features, vascular risk factors, cognitive function, and neuropsychiatric symptoms, were compared between VCI with VH (VH+) and without VH (VH-). Among the 1281 patients analysed, 155 (12.1%) had VH. The VH+ group was older (t = 5.07; p < 0.001), was more likely to be female (χ ² = 13.46; p < 0.001), and has a higher clinical dementia rating (χ ² = 70.51; p < 0.001). After adjusting for age, gender, and disease severity, the VH+ group had poorer cognition and more severe neuropsychiatric symptoms. The VH+ group was more associated with DLB features in fluctuating cognition (OR = 2.48; p < 0.001), parkinsonism (OR = 1.85; p = 0.001), rapid eye movement (REM) behavioral disorder (OR = 4.56; p < 0.001), and ≧2 DLB core features (OR = 26.01; p < 0.001). VCI patients with VH tend to have more severe dementia, neuropsychiatric symptoms, and poorer cognitive function. Additionally, highly associated with clinical DLB features in VCI with VH raised the possibility of mixed pathology with DLB in this group. More than two core features in VCI might help in diagnosing a mixed pathology with DLB.

Relevance of 5-HT2A Receptor Modulation of Pyramidal Cell Excitability for Dementia-Related Psychosis: Implications for Pharmacotherapy

Psychosis occurs across a wide variety of dementias with differing etiologies, including Alzheimer's dementia, Parkinson's dementia, Lewy body dementia, frontotemporal dementia, and vascular dementia. Pimavanserin, a selective serotonin 5-HT_2A receptor (5-HT_2AR) inverse agonist, has shown promising results in clinical trials by reducing the frequency and/or severity of hallucinations and delusions and the risk of relapse of these symptoms in patients with dementia-related psychosis. A literature review was conducted to identify mechanisms that explain the role of 5-HT_2ARs in both the etiology and treatment of dementia-related psychosis. This review revealed that most pathological changes commonly associated with neurodegenerative diseases cause one or more of the following events to occur: reduced synaptic contact of gamma aminobutyric acid (GABA)-ergic interneurons with glutamatergic pyramidal cells, reduced cortical innervation from subcortical structures, and altered 5-HT_2AR expression levels. Each of these events promotes increased pyramidal cell hyperexcitability and disruption of excitatory/inhibitory balance, facilitating emergence of psychotic behaviors. The brain regions affected by these pathological changes largely coincide with areas expressing high levels of 5-HT_2ARs. At the cellular level, 5-HT_2ARs are most highly expressed on cortical glutamatergic pyramidal cells, where they regulate pyramidal cell excitability. The common effects of different neurodegenerative diseases on pyramidal cell excitability together with the close anatomical and functional connection of 5-HT_2ARs to pyramidal cell excitability may explain why suppressing 5-HT_2AR activity could be an effective strategy to treat dementia-related psychosis.

The Role of EEG in the Diagnosis, Prognosis and Clinical Correlations of Dementia with Lewy Bodies-A Systematic Review

Despite improvements in diagnostic criteria for dementia with Lewy bodies (DLB), the ability to discriminate DLB from Alzheimer’s disease (AD) and other dementias remains suboptimal. Electroencephalography (EEG) is currently a supportive biomarker in the diagnosis of DLB. We performed a systematic review to better clarify the diagnostic and prognostic role of EEG in DLB and define the clinical correlates of various EEG features described in DLB. MEDLINE, EMBASE, and PsycINFO were searched using search strategies for relevant articles up to 6 August 2020. We included 43 studies comparing EEG in DLB with other diagnoses, 42 of them included a comparison of DLB with AD, 10 studies compared DLB with Parkinson’s disease dementia, and 6 studies compared DLB with other dementias. The studies were visual EEG assessment (6), quantitative EEG (35) and event-related potential studies (2). The most consistent observation was the slowing of the dominant EEG rhythm (<8 Hz) assessed visually or through quantitative EEG, which was observed in ~90% of patients with DLB and only ~10% of patients with AD. Other findings based on qualitative rating, spectral power analyses, connectivity, microstate and machine learning algorithms were largely heterogenous due to differences in study design, EEG acquisition, preprocessing and analysis. EEG protocols should be standardized to allow replication and validation of promising EEG features as potential biomarkers in DLB.

Examining the Link Between Cardiovascular Risk Factors and Neuropsychiatric Symptoms in Mild Cognitive Impairment and Major Depressive Disorder in Remission

BACKGROUND

Cardiovascular risk factors (CVRFs) have been linked to both depression and cognitive decline but their role in neuropsychiatric symptoms (NPS) has yet to be clarified.

OBJECTIVE

Understanding the role of CVRFs in the etiology of NPS for prospective treatments and preventive strategies to minimize these symptoms.

METHODS

We examined the distribution of NPS using the Neuropsychiatric Inventory (NPI) scores in three cohorts from the Prevention of Alzheimer's Dementia with Cognitive Remediation Plus Transcranial Direct Current Stimulation in Mild Cognitive Impairment and Depression (PACt-MD) study: older patients with a lifetime history of major depressive disorder (MDD) in remission, patients with mild cognitive impairment (MCI), and patients with combined MCI and MDD. We also examined the link between individual NPS and CVRFs, Framingham risk score, and Hachinski ischemic score in a combined sample.

RESULTS

Analyses were based on a sample of 140 subjects, 70 with MCI, 38 with MCI plus MDD, and 32 with MDD. There was no effect of age, gender, education, cognition, or CVRFs on the presence (NPI >1) or absence (NPI = 0) of NPS. Depression was the most prevalent affective NPS domain followed by night-time behaviors and appetite changes across all three diagnostic groups. Agitation and aggression correlated negatively while anxiety, disinhibition, night-time behaviors, and irritability correlated positively with CVRFs (all p-values <0.05). Other NPS domains showed no significant association with CVRFs.

CONCLUSION

CVRFs are significantly associated with individual NPI sub-scores but not with total NPI scores, suggesting that different pathologies may contribute to different NPS domains.

Behavior in subcortical vascular dementia with sight pathologies: visual hallucinations as a consequence of precocious gait imbalance and institutionalization

BACKGROUND

Subcortical vascular dementia (sVAD) is considered the most frequent dementia in old population, and it is due to a small vessel disease. It has a very specific nosography, where the dominant factors are dysexecutive functions, depression, and apathy. Very few studies described visual hallucinations in sVAD, apart from in the final stages of it.

METHODS

This study recruited 577 patients with a diagnosis of sVAD associated with major ocular pathologies and 1118 patients with sVAD without any significant ocular pathology: Patients were followed up for 24 months. We studied the influence of ocular pathologies in precocious visual hallucinations, on behavior disorder (aggressiveness), and gait disorders (instability, fells). We registered the necessity of neuropsychiatric therapies, incidence of hospitalization, and institutionalization.

RESULTS

What emerges from our study is that the ocular comorbidities might change the behavior profile of dementia, provoking behavioral alterations, and the need for therapies with adverse effects. As far as old age is a complicated status of life, many factors can modify its development. The possible contribution of multiple biological events cannot be neglected, particularly the underlying influence of chronic diseases as well as the geriatric conditions, per se, might compromise the cognitive functions and the pathological conditions. Ocular pathology as a superimposing event in sVAD might worse the outcome. A correct and rapid identification of critical patients might be relevant for the dynamic life events in these patients and their caregivers.

Prevalence and Clinical Implications of the Mirror and TV Signs in Advanced Alzheimer's Disease and Dementia with Lewy Bodies

Objective

To explore the prevalence and clinical implications of the mirror and TV signs in the moderate to advanced stages of Alzheimer's disease (AD) and dementia with Lewy bodies (DLB).

Methods

We retrospectively examined the prevalence of clinical and psychiatric symptoms including the mirror and TV signs in 200 subjects with AD and 200 with DLB and evaluated the relationships among the symptoms.

Results

The mirror sign was found in 3.0% of AD and 4.5% of DLB subjects. The TV sign was found in 1.5% of AD and 4.0% of DLB subjects. The prevalence of the mirror and TV signs was not significantly different between the AD and DLB groups. Visual hallucination, visual illusion, misidentification of person, and sleep talking were significantly more frequent in DLB than in AD subjects. The mirror sign was significantly associated with lower Mini-Mental State Examination scores, whereas the TV sign was significantly associated with the misidentification of person.

Conclusions

Both the mirror and TV signs were rare even in the moderate to advanced stages of AD and DLB. The mirror sign may be independent from other delusional misidentification syndromes (DMSs). Being associated mainly with global cognitive decline, the mirror sign is unlikely attributed to any specific cognitive impairment or the dysfunction of localized brain areas. In contrast, the TV sign was significantly more often coexistent with the misidentification of person, suggesting that the TV sign may partly share common neuropsychological mechanisms with DMSs.

Psychosis in neurodegenerative disorders: recent developments

PURPOSE OF REVIEW

This review presents the latest developments covered in the literature regarding psychosis in neurodegenerative disorders and discusses possible future research directions.

RECENT FINDINGS

Recent findings in the field of psychosis and neurodegenerative disorders revolve around four main themes. The first theme is the impact of sex on the expression of psychosis in neurodegenerative disorders. The second theme focuses on the relationship between psychosis and neurodegenerative disease biomarkers. The third concerns how psychotic symptoms in neurodegenerative disorders may share common mechanisms with other primary psychotic disorders such as schizophrenia. Finally, there have been some promising developments in the area of therapeutics to treat dementia-related psychosis involving both established and novel treatments.

SUMMARY

New findings in the field of neurodegeneration and psychosis parallel new directions in the field of neurodegeneration in general. More specifically, we have seen a shift in focus to issues highlighting the role of sex, biomarkers, translation to other disorders, and therapeutics.

APOE ɛ4/ɛ4 Is Associated with Aberrant Motor Behavior Through Both Lewy Body and Cerebral Amyloid Angiopathy Pathology in High Alzheimer's Disease Pathological Load

BACKGROUND

Aberrant motor behavior (AMB) is a neuropsychiatric symptom (NPS) prevalent in Alzheimer's disease (AD), known to cause great distress to both patients and caregivers. Apolipoprotein E4 (APOE4) is the most important genetic predictor of AD, and it has been associated with high NPS prevalence.

OBJECTIVE

To investigate the neuropathological substrates and risk factors associated with AMB in AD patients.

METHODS

Cases with Braak stage I-II and CERAD 0-1 were classified as Low AD (LAD), while Braak stage III-IV and CERAD 2 were grouped as Intermediate AD (IAD). Cases with Braak stage V-VI and CERAD 3 were classified as High AD (HAD) in accordance with NIA-Reagan criteria. All cases were stratified by APOE genotype, yielding No ɛ4 & ɛ4 and ɛ4/ɛ4 groups depending on ɛ4 copy number within APOE. Presence of AMB was assessed using NPI-Q.

RESULTS AND CONCLUSION

AMB increased in parallel with CERAD and Braak & Braak scores. Hypercholesterolemia, but no other cardiovascular risk factors, was associated with AMB in HAD. AMB prevalence in HAD was significantly increased in the presence of two APOEɛ4 alleles as compared to No ɛ4 & ɛ4. The relationship between homozygous APOE4 and AMB was strongly associated with the presence of both Lewy bodies and cerebral amyloid angiopathy pathologies in both sexes.

Synaptic Proteome Compensation and Resilience to Psychosis in Alzheimer's Disease

OBJECTIVE

The presence of psychosis in Alzheimer's disease denotes a phenotype with more rapid cognitive deterioration than in Alzheimer's disease without psychosis. Discovery of novel pharmacotherapies that engage therapeutic targets for prevention or treatment of Alzheimer's disease with psychosis would benefit from identifying the neurobiology of resilience to psychosis in Alzheimer's disease. The primary objective of this study was to determine whether alterations in the synaptic proteome were associated with resilience to psychotic symptoms in Alzheimer's disease and, if present, were independent of neuropathologic burden.

METHOD

Quantitative immunohistochemistry was used to measure multiple neuropathologies in dorsolateral prefrontal cortex from subjects with early and middle-stage Alzheimer's disease who differed in psychosis status. Synaptic proteins were quantified by liquid chromatography-mass spectrometry in gray matter homogenates from these subjects and from neuropathologically unaffected subjects. The synaptic proteome was similarly evaluated in cortical gray matter homogenate and in postsynaptic density fractions from an APPswe/PSEN1dE9 mouse model of amyloidosis with germline reduction in Kalrn, which has been shown to confer resilience to progression of psychosis-associated behaviors relative to APPswe/PSEN1dE9 alone.

RESULTS

Subjects resilient to psychotic symptoms in Alzheimer's disease had higher levels of synaptic proteins compared with those with psychosis and unaffected control subjects. Neuropathologic burden predicted less than 20% of the variance in psychosis status and did not account for the synaptic protein level differences between groups. Reduction of Kalrn in APPswe/PSEN1dE9 mice resulted in higher levels of synaptic proteins in cortical homogenate and normalized protein levels in the postsynaptic density.

CONCLUSIONS

Accumulation of synaptic proteins, particularly those that are enriched in the postsynaptic density, is associated with resilience to psychosis in Alzheimer's disease. One candidate mechanism for this synaptic proteome compensation is alteration in levels of proteins that facilitate the transport of synaptic proteins to and from the postsynaptic density.

Study on epidemiology of cognitive dysfunction after stroke in the population over the age of 45 in Inner Mongolia

OBJECTIVE

To analyze the prevalence of different degrees vascular cognitive impairment (VCI) in stroke and the characteristics of demography distribution in Inner Mongolia. In order to provide reference data and theoretical guidance for the prevention and treatment of VCI after stroke in the area.

METHODS

Stratified multi-stage random sampling was used to extract six regions of Inner Mongolia as the first sampling cluster; and then the corresponding banners (counties) were selected randomly as the secondary sampling cluster; according to the number of patient required to investigation, the corresponding number of communities was randomly selected from the secondary sampling cluster. According to the diagnostic criteria of 'Guidelines for the diagnosis and treatment of vascular cognitive impairment' and National Institute of Neurological Disorders and Stroke convened an International Workshop with support from the Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN), we screened all stroke patients aged 45 or older from each community, a total of 444 patients participated in the questionnaire and various scale assessments.

RESULTS

The prevalence of VCI, vascular cognitive impairment no dementia and vascular dementia was 80.41%, 34.46% and 45.95% respectively. The prevalence of VCI in stroke was significantly different in different nationality, age and education level (P < 0.05), and there was no significant difference in gender, occupation, marital status and family structure (P > 0.05).

CONCLUSION

The prevalence of VCI after stroke was higher in Inner Mongolia, and VCI had a relatively high morbidity in old age people and person with less education in Chinese Han population.

Psychosis in "Cognitively Asymptomatic" Elderly Subjects is Associated With Neuritic Plaque Load, Not Neurofibrillary Tangles

INTRODUCTION

Despite having severe Alzheimer disease pathology, some individuals remain cognitively asymptomatic (cASYM). To explore noncognitive manifestations in these cASYM individuals, we aim to investigate the prevalence and pathologic substrates of psychosis.

METHODS

Data were obtained from the National Alzheimer's Coordinating Center. The Neuropsychiatric Inventory Questionnaire, quick version was used to evaluate presence of psychosis. Subjects with Mini-Mental Status Examination score of ≥24 with frequent neuritic plaques (NPs) were defined as NPcASYM, and those with Braak and Braak stage of neurofibrillary tangles of V/VI were defined as NTcASYM (both groups collectively designated cASYM). Logistic regression analysis was used to examine the association between NP and neurofibrillary tangle severity and psychosis accounting for potential confounders.

RESULTS

We identified 667 subjects with Mini-Mental Status Examination score of ≥24, of which 137 were NPcASYM and 96 were NTcASYM. NPcASYM were at significantly higher risk of having psychosis compared with those with moderate or sparse/no NP (odds ratio, 2.47; 95% confidence interval, 1.54-3.96). NTcASYM were also at higher risk compared with those with Braak and Braak stage I to IV, but the association explained by the effect of Lewy body pathology and microinfarcts.

DISCUSSION

The load of NP may be an important substrate of psychosis in individuals who show no gross cognitive symptoms.

Gender and Pathology-Specific Effect of Apolipoprotein E Genotype on Psychosis in Alzheimer's Disease

BACKGROUND

Symptoms of psychosis is one of the common clinical manifestations of Alzheimer's disease (AD). However, the pathophysiology behind psychosis is unknown.

OBJECTIVE

The aim of the present study was to explore the relationship between Apolipoprotein E (APOE) genotype, Lewy body pathology, and psychosis in AD.

METHOD

The data was obtained from the National Alzheimer's disease Coordinating Centre (NACC), using the Uniform Data Set and the Neuropathology Data Set. Subjects with frequent neuritic plaque on CERAD, and Braak Stage of V or VI, corresponding to high probability of AD based on the NIA-AA Regan criteria were included in the analysis.

RESULTS

Subjects with two copies of ε4 alleles were significantly more likely to develop psychosis, both delusions and/or hallucinations, during the course of their illness. This association was gender-specific, only reaching significance in females. Our findings further showed that presence of two copies of ε4 allele was positively associated with the formation of Lewy bodies. Only in females with Lewy bodies was the effect of two copies of ε4 allele significant, reaching an odd ratio of 4.5.

CONCLUSION

The APOE ε4 allele has a female-specific effect in inducing psychosis in AD through the formation of Lewy bodies.

Psychosis and Clinical Outcomes in Alzheimer Disease: A Longitudinal Study

OBJECTIVE

Psychotic symptoms are a common feature in Alzheimer disease (AD), occurring in approximately 40% of patients. These symptoms are associated with worse clinical outcomes. Comparatively little research, however, has distinguished delusions and hallucinations, which may have distinct clinical, neuropathological, and genetic correlates. To address this, the current study examined the clinical outcomes associated with delusions and hallucinations in AD.

DESIGN

Three-year observational study.

SETTING

Nine memory clinics in Australia.

PARTICIPANTS

A total of 445 patients with AD.

MEASUREMENTS

Measures of neuropsychiatric symptoms, dementia severity, cognition, function, caregiver burden, and medication use were completed annually for 3 years with additional assessments at 3 months and 6 months in the first year. Mortality data were obtained from state registries approximately 5 years after the study.

RESULTS

Of 445 patients, 102 (22.9%) developed only delusions, 39 (8.8%) developed only hallucinations, and 84 (18.9%) developed both symptoms. Delusions and hallucinations were both associated with greater dementia severity, poorer cognition and function, higher levels of other neuropsychiatric symptoms, and greater caregiver burden. The presence of both symptoms was associated with worse outcomes than only one of these symptoms. Delusions, both by themselves and in combination with hallucinations, predicted institutionalization. Antipsychotic medication use predicted mortality.

CONCLUSIONS

Delusions and hallucinations independently and in combination are associated with poor clinical outcomes. The findings highlight the challenges managing these patients, particularly given the high levels of caregiver burden associated with psychotic symptoms and the likely mortality arising from antipsychotic medication.

The Role of Cerebrovascular Disease on Cognitive and Functional Status and Psychosis in Severe Alzheimer's Disease

Background: The pathophysiology behind psychosis in patients with Alzheimer’s disease (AD) remains unknown. Recently, vascular risk factors have been recognized as important modifiers of the clinical presentation of AD.

Objective: The purpose of our study is to investigate the mechanism through which vascular risk factors mediate psychosis and whether or not it involves cerebrovascular lesions.

Methods: Data was provided by the National Alzheimer’s Coordinating Centre. The Uniform Data Set was used to collect information on subject-reported history of vascular risk factors, clinician-reported state of cognitive performance, and presence of psychosis based on the Neuropsychiatric Inventory Questionnaire (NPI-Q). The Neuropathology Data Set was used to evaluate the presence of vascular lesions and the severity of AD pathology. Subjects with high probability of AD based on the NIA/AA Reagan criteria were included in the analysis.

Results: We identified 1,459 patients with high probability of AD and corresponding NPI-Q scores. We confirmed the association between hypertension and diabetes on psychosis, specifically in delusions and the co-occurrence of delusions and hallucinations. Furthermore, the presence of white matter rarefaction based on pathological evaluation was associated with hallucinations. A history of vascular risk factors was positively associated with vascular lesions. However, vascular lesions in the presence of vascular risk factors did not increase the likelihood of psychosis. Furthermore, vascular lesions were not associated with greater cognitive or functional impairments in this group with severe AD pathology.

Conclusion: Vascular risk factors and vascular lesions are independently associated with psychosis in patients with severe AD. However, vascular lesions are not the mechanism through which vascular risk factors mediate psychosis.

Association Between Psychosis Phenotype and APOE Genotype on the Clinical Profiles of Alzheimer's Disease

BACKGROUND

Psychosis is a common phenomenon in Alzheimer's disease (AD). The APOE ε4 allele is the strongest genetic risk factor for the development of AD, but its association with psychosis remains unclear.

OBJECTIVE

We investigated the associations between psychosis, subdivided into delusions and hallucinations, as well as APOE ε4 allele on cognitive and functional outcomes. Secondarily, we investigated the associations between APOE ε4, Lewy bodies, and psychosis.

METHODS

Data from the National Alzheimer's Coordinating Center (NACC) were used. Nine hundred patients with a confirmed diagnosis of AD based on the NIA-AA Reagan were included in the analysis. Global cognition was assessed using the Mini-Mental State Exam (MMSE) and functional status was assessed using the Functional Activities Questionnaire (FAQ). Psychosis status was determined using the Neuropsychiatric Inventory Questionnaire (NPI-Q). Factorial design was used to assess the effects of psychosis and APOE ε4, as well as their interaction.

RESULTS

Psychosis and the presence of APOE ε4 were both associated with lower MMSE scores, while only psychosis was associated with higher FAQ scores. Furthermore, patients with hallucinations had lower MMSE and higher FAQ scores than patients with only delusions. There was a significant interaction effect between psychosis and APOE ε4 on MMSE scores, with APOE ε4 negatively affecting patients with hallucinations-only psychosis. APOE ε4 was positively associated with the presence of Lewy body pathology, and both were found to be more prevalent in psychotic patients, with a stronger association with hallucinations.

CONCLUSION

Psychosis in AD was associated with greater cognitive and functional impairments. Patients with hallucinations-with or without delusions-conferred even greater deficits compared to patients with only delusions. The APOE ε4 allele was associated with worse cognition, especially for patients with hallucination-only psychosis. APOE ε4 may mediate cognitive impairment in the hallucinations phenotype through the development of Lewy bodies. Our findings support that subtypes of psychosis should be evaluated separately.

Clinical and neurocognitive aspects of hallucinations in Alzheimer's disease

Due to their prevalence, hallucinations are considered as one of the most frequent psychotic symptoms in Alzheimer's disease (AD). These psychotic manifestations reduce patients' well-being, increase the burden of caregivers, contribute to early institutionalization, and are related with the course of cognitive decline in AD. Considering their consequences, we provide a comprehensive account of the current state of knowledge about the prevalence and characteristics of hallucinations in AD. We propose a comprehensive and testable theoretical model about hallucinations in AD: the ALZHA (ALZheimer and HAllucinations) model. In this model, neurological, genetic, cognitive, affective, and iatrogenic factors associated with hallucinations in AD are highlighted. According to the ALZHA model, hallucinations in AD first involve trait markers (i.e., cognitive deficits, neurological deficits, genetic predisposition and/or sensory deficits) to which state markers that may trigger these experiences are added (e.g., psychological distress and/or iatrogenic factors). Finally, we provide recommendations for assessment and management of these psychotic manifestations in AD, with the aim to benefit patients, caregivers, and health professionals.

Determining the impact of psychosis on rates of false-positive and false-negative diagnosis in Alzheimer's disease

INTRODUCTION

The rate of clinical misdiagnosis of Alzheimer's disease (AD) and how psychosis impacts that clinical judgment is unclear.

METHODS

Using data from National Alzheimer's Coordinating Center, we compared the clinical and neuropathologic diagnosis in patients with a diagnosis of AD with autopsy and in neuropathology-confirmed AD cases (n = 961). We determined the rate of true positives, false positives, and false negatives in patients with and without psychosis.

RESULTS

A total of 76% received a correct AD diagnosis, 11.9% had a false-negative diagnosis, and 12.1% had a false-positive diagnosis of AD. Psychotic patients had a higher rate of false-negative diagnosis and a lower rate of false-positive diagnosis of AD compared with nonpsychotic patients.

DISCUSSION

Patients with psychosis were five times more likely to be misdiagnosed as dementia with Lewy bodies, whereas patients without psychosis were more likely to be falsely diagnosed with AD when vascular pathology is the underlying neuropathologic cause of dementia.

Changes in intracranial venous blood flow and pulsatility in Alzheimer's disease: A 4D flow MRI study

Cerebral blood flow, arterial pulsation, and vasomotion may be important indicators of cerebrovascular health in aging and diseases of aging such as Alzheimer's disease. Noninvasive markers that assess these characteristics may be helpful in the study of co-occurrence of these diseases and potential additive and interacting effects. In this study, 4D flow MRI was used to measure intra-cranial flow features with cardiac-gated phase contrast MRI in cranial arteries and veins. Mean blood flow and pulsatility index as well as the transit time of the peak flow from the middle cerebral artery to the superior sagittal sinus were measured in a total of 104 subjects comprising of four groups: (a) subjects with Alzheimer's disease, (b) age-matched controls, (c) subjects with mild cognitive impairment, and (d) a group of late middle-aged with parental history of sporadic Alzheimer's disease. The Alzheimer's disease group exhibited: a significant decrease in mean blood flow in the superior sagittal sinus, transverse sinus, middle cerebral artery, and internal carotid arteries; a significant decrease of the peak and end diastolic blood flow in the middle cerebral artery and superior sagittal sinus; a faster transmission of peak flow from the middle cerebral artery to the superior sagittal sinus and increased pulsatility index along the carotid siphon.

Clinical presentations and epidemiology of vascular dementia

Cerebrovascular and cardiovascular diseases cause vascular brain injury that can lead to vascular cognitive impairment (VCI). VCI is the second most common neuropathology of dementia and mild cognitive impairment (MCI), accounting for up to one-third of the population risk. It is frequently present along with other age-related pathologies such as Alzheimer's disease (AD). Multiple etiology dementia with both VCI and AD is the single most common cause of later life dementia. There are two main clinical syndromes of VCI: post-stroke VCI in which cognitive impairment is the immediate consequence of a recent stroke and VCI without recent stroke in which cognitive impairment is the result of covert vascular brain injury detected only on neuroimaging or neuropathology. VCI is a syndrome that can result from any cause of infarction, hemorrhage, large artery disease, cardioembolism, small vessel disease, or other cerebrovascular or cardiovascular diseases. Secondary prevention of further vascular brain injury may improve outcomes in VCI.

Neuropsychiatric Symptoms in Mild Cognitive Impairment

OBJECTIVE

Neuropsychiatric symptoms (NPS) may be the first manifestation of an underlying neurocognitive disorder. We undertook a review to provide an update on the epidemiology and etiological mechanisms of NPS that occur in mild cognitive impairment (MCI) and just before the onset of MCI. We discuss common clinical presentations and the implications for diagnosis and care.

METHOD

The authors conducted a selective review of the literature regarding the emergence of NPS in late life, before and after the onset of MCI. We discuss recent publications that explore the epidemiology and etiological mechanisms of NPS in the earliest clinical stages of these disorders.

RESULTS

NPS have been reported in 35% to 85% of adults with MCI and also occur in advance of cognitive decline. The occurrence of NPS for the first time in later life should increase suspicion for an underlying neurocognitive disorder. The presenting symptom may provide a clue regarding the etiology of the underlying disorder, and the co-occurrence of NPS may herald a more accelerated cognitive decline.

CONCLUSIONS

NPS are prevalent in the early clinical stages of neurocognitive disorders and can serve as both useful diagnostic and prognostic indicators. Recognition of NPS as early manifestations of neurocognitive disorders will become increasingly important as we move towards preventative strategies and disease-modifying treatments that may be most effective when deployed in the earliest stages of disease.