Depression, delusions, and hallucinations in Alzheimer's disease: no relationship to apolipoprotein E genotype

Neuropsychiatric symptoms and ApoE genotype in older adults without dementia: a cross-sectional study

BACKGROUND

The ApoE genotype and neuropsychiatric symptoms (NPS) are known risk factors for cognitive decline in older adults. However, the interaction between these variables is still unclear. The aim of this study was to determine the association between the presence of the ApoE ε4 allele and the occurrence of NPS in older adults without dementia.

METHODS

In this cross-sectional investigation we determined the apolipoprotein E (ApoE) genotype of 74 older adults who were either cognitively normal (20.3% / Clinician Dementia Rating Scale (CDR): 0) or had mild cognitive impairment (MCI: 79.7% / CDR: 0.5). We used a comprehensive cognitive assessment protocol, and NPS were estimated by the Neuropsychiatric Inventory-Clinician Rating Scale (NPI-C), Mild Behavioural Impairment-Checklist (MBI-C), Hamilton Rating Scale for Depression (HAM-D), and Apathy Inventory.

RESULTS

ApoE ε4 carriers had higher MBI-C total scores than ApoE ε4 noncarriers. Correlations between NPS and ApoE genotype were observed for two NPI-C domains, although in opposite directions: the ApoE ε4 allele was associated with a 1.8 unit decrease in the estimated aberrant motor disturbance score and with a 1.3 unit increase in the estimated appetite/eating disorders score. All fitted models were significant, except for the one fitted for the domain delusions from the NPI-C. Among individuals with amnestic MCI, ε4 carriers presented higher depression score (HAM-D) than noncarriers; in turn, ε4 noncarriers exhibited higher aggression score (NPI-C) than ε4 carriers.

CONCLUSIONS

Our analyses showed associations between NPS and the presence of the ApoE ε4 allele in two NPI-C domains, despite the sample size. Furthermore, compared to noncarriers, the presence of the ApoE ε4 correlated positively with appetite/eating disorders and negatively with aberrant motor disturbance domain. Examination of the amnestic MCI group displayed significant, although weak, associations. Therefore, ε4 carriers exhibited higher depression scores according to the HAM-D scale compared to ε4 noncarriers. Conversely, ε4 noncarriers had higher scores in the aggression domain of the NPI-C than ε4 carriers.

Alzheimer's disease phenotype based upon the carrier status of the apolipoprotein E ɛ4 allele

The apolipoprotein E ɛ4 allele (APOE4) is universally acknowledged as the most potent genetic risk factor for Alzheimer's disease (AD). APOE4 promotes the initiation and progression of AD. Although the underlying mechanisms are unclearly understood, differences in lipid-bound affinity among the three APOE isoforms may constitute the basis. The protein APOE4 isoform has a high affinity with triglycerides and cholesterol. A distinction in lipid metabolism extensively impacts neurons, microglia, and astrocytes. APOE4 carriers exhibit phenotypic differences from non-carriers in clinical examinations and respond differently to multiple treatments. Therefore, we hypothesized that phenotypic classification of AD patients according to the status of APOE4 carrier will help specify research and promote its use in diagnosing and treating AD. Recent reviews have mainly evaluated the differences between APOE4 allele carriers and non-carriers from gene to protein structures, clinical features, neuroimaging, pathology, the neural network, and the response to various treatments, and have provided the feasibility of phenotypic group classification based on APOE4 carrier status. This review will facilitate the application of APOE phenomics concept in clinical practice and promote further medical research on AD.

A Systematic Analysis on the Genes and Their Interaction Underlying the Comorbidity of Alzheimer's Disease and Major Depressive Disorder

Background

During the past years, clinical and epidemiological studies have indicated a close relationship between Alzheimer's disease (AD) and other mental disorders like major depressive disorder (MDD). At the same time, a number of genes genetically associated with AD or MDD have been detected. However, our knowledge on the mechanisms that link the two disorders is still incomplete, and controversies exist. In such a situation, a systematic analysis on these genes could provide clues to understand the molecular features of two disorders and their comorbidity.

Methods

In this study, we compiled the genes reported to be associated with AD or MDD by a comprehensive search of human genetic studies and genes curated in disease-related database. Then, we investigated the features of the shared genes between AD and MDD using the functional enrichment analysis. Furthermore, the major biochemical pathways enriched in the AD- or MDD-associated genes were identified, and the cross talks between the pathways were analyzed. In addition, novel candidate genes related to AD and MDD were predicted in the context of human protein-protein interactome.

Results

We obtained 650 AD-associated genes, 447 MDD-associated genes, and 77 shared genes between AD and MDD. The functional analysis revealed that biological processes involved in cognition, neural development, synaptic transmission, and immune-related processes were enriched in the common genes, indicating a complex mechanism underlying the comorbidity of the two diseases. In addition, we conducted the pathway enrichment analysis and found 102 shared pathways between AD and MDD, which involved in neuronal development, endocrine, cell growth, and immune response. By using the pathway cross-talk analysis, we found that these pathways could be roughly clustered into four modules, i.e., the immune response-related module, the neurodevelopmental module, the cancer or cell growth module, and the endocrine module. Furthermore, we obtained 37 novel candidate genes potentially related to AD and MDD with node degrees > 5.0 by mapping the shared genes to human protein-protein interaction network (PPIN). Finally, we found that 37 novel candidate genes are significantly expressed in the brain.

Conclusion

These results indicated shared biological processes and pathways between AD and MDD and provided hints for the comorbidity of AD and MDD.

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.

Trajectories of depression symptoms over time differ by APOE4 genotype in older adults with type 2 diabetes

OBJECTIVES

The APOE-ε4 genotype has been associated with old-age depression, but this relationship has been rarely investigated in type 2 diabetes (T2D) older adults, who are at significantly increased risk for depression, a major contributor to T2D complications. We examined whether trajectories of depression symptoms over time differ by APOE-ε4 genotype in older adults with T2D.

METHODS

Participants (n = 754 [13.1% APOE-ε4 carrier]s) were from the longitudinal Israel Diabetes and Cognitive Decline (IDCD) study. They were initially cognitively normal and underwent evaluations of depression approximately every 18 months using the 15-item version of the Geriatric Depression Scale (GDS) and the depression subscale of the Neuropsychiatric Inventory (NPI). APOE was defined as a dichotomy of ε4 carriers and non-carriers. We used Hierarchical Linear Mixed Models (HLMM) that modeled the effects of APOE status on repeated GDS and NPI-depression scores in an unadjusted model (Model 1), adjusting for demographic factors (Model 2) and additionally adjusting for cardiovascular factors and global cognition (Model 3).

RESULTS

Participants' mean age was 71.37 (SD = 4.5); 38.2% female. In comparison to non-carriers, APOE-ε4 carriers had lower mean GDS scores (β = -0.46, p = 0.018) and lower NPI-depression scores (β = -0.170, p = 0.038) throughout all study follow period. The groups did not differ in the slope of change over time in GDS (β = -0.005, p = 0.252) or NPI-depression (β = -0.001, p = 0.994) scores. Additional adjustment for cardiovascular factors and global cognition did not alter these results.

CONCLUSIONS

In older adults with T2D, APOE-ε4 carriers have less depressive symptoms in successive measurements suggesting they may be less susceptible to depression.

Apolipoprotein E ϵ4 allele and neuropsychiatric symptoms among older adults in Central Africa (EPIDEMCA study)

OBJECTIVES

To evaluate the association between neuropsychiatric symptoms and apolipoprotein E (APOE) ϵ4 allele among older people in Central African Republic (CAR) and the Republic of Congo (ROC).

DESIGN

Multicenter population-based study following a two-phase design.

SETTING

From 2011 to 2012, rural and urban areas of CAR and ROC.

PARTICIPANTS

People aged 65 and over.

MEASUREMENTS

Following screening using the Community Screening Interview for Dementia, participants with low cognitive scores (CSI-D ≤ 24.5) underwent clinical assessment. Dementia diagnosis followed the DSM-IV criteria and Peterson's criteria were considered for Mild Cognitive Impairment (MCI). Neuropsychiatric symptoms were evaluated through the brief version of the Neuropsychiatric Inventory (NPI-Q). Blood samples were taken from all consenting participants before APOE genotyping was performed by polymerase chain reaction (PCR). Logistic regression models were used to evaluate the association between the APOE ϵ4 allele and neuropsychiatric symptoms.

RESULTS

Overall, 322 participants had complete information on both neuropsychiatric symptoms and APOE status. Median age was 75.0 years and 81.1% were female. Neuropsychiatric symptoms were reported by 192 participants (59.8%) and at least 1 APOE ϵ4 allele was present in 135 (41.9%). APOE ϵ4 allele was not significantly associated with neuropsychiatric symptoms but showed a trend toward a protective effect in some models.

CONCLUSION

This study is the first one investigating the association between APOE ϵ4 and neuropsychiatric symptoms among older people in sub-Saharan Africa (SSA). Preliminary findings indicate that the APOE ϵ4 allele was not associated with neuropsychiatric symptoms. Further research seems, however, needed to investigate the protective trend found in this study.

Minor and subthreshold depressive disorders in Alzheimer's disease: A systematic review and meta-analysis of prevalence studies

BACKGROUND

Depressive symptoms are common in Alzheimer's disease (AD) and negatively impact patient well-being. The main aim of the present study was to establish summary estimates for the prevalence of minor depressive disorder (MinD) and subthreshold depression in AD and synthesise evidence on prognosis and management of these symptoms in order to inform clinical guidelines.

METHODS

Systematic review and meta-analysis of cross-sectional and longitudinal studies of prevalence, prognosis, and treatments for minor and subthreshold depression in AD. We searched MEDLINE, Embase, PsycINFO and CINAHL. We included studies that reported prevalence of subthreshold depressive disorders and those reporting data on validity of diagnostic criteria, mechanisms, or randomised controlled clinical trials (RCTs) testing effectiveness of interventions. Estimates of prevalence were pooled using random-effects meta-analyses. Two authors screened articles and independently extracted data on study characteristics.

RESULTS

We reviewed 5671 abstracts, retrieved 621 full text articles and included a total of 15 studies. Pooling data from 10 studies showed that prevalence for MinD in AD was 22.0% (95% CI 16.0 to 28.0). Prevalence for a clinical diagnosis of MinD (DSM-III-R and DSM-IV) was 26.0% (95% CI 20.0 to 32.0; 6 studies). People with MinD experienced higher levels of neuropsychiatric symptoms, functional and cognitive decline, although studies remain cross-sectional. Neither sertraline nor a carer intervention were effective in reducing symptoms.

CONCLUSION

This review finds that MinD is prevalent in people with a diagnosis of AD and requires clinical attention. Research is warranted to develop effective interventions to treat and prevent these symptoms.

The Impact of Angiotensin-Converting Enzyme Gene on Behavioral and Psychological Symptoms of Dementia in Alzheimer’s Disease

Background:

The Angiotensin-Converting Enzyme (ACE) gene has drawn attention for its possible role in regulating the degradation of β-amyloid (Aβ), yet its role in affecting the cognitive and psychiatric symptoms of Alzheimer`s Disease (AD) patients has yet to be elucidated.

Objective:

This study aimed to investigate whether the ACE gene acts as a risk factor of Behavioral and Psychological Symptoms of Dementia (BPSD) in the AD population.

Method:

The genotyping of ACE and Apolipoprotein E gene with allele ε4(APOEε4) was determined among 360s clinically diagnosed AD patients. Symptoms and severity of BPSD were evaluated annually via Neuropsychiatric Inventory (NPI).

Results:

At the base measurement of the first year of patient recruitment, there were no significant contributory risk factors to NPI score. In the two-year follow-up, ACE insertion polymorphism showed a significant risk (adjusted odds ratio=1.65, 95% CI=1.1- 2.5, p=0.019) of progression of NPI total score.

Conclusion:

ACE gene is involved in aggravating BPSD among AD patients.

Homozygosity in the APOE 3 Polymorphism Is Associated With Less Depression and Higher Serum Low-Density Lipoprotein in Chinese Elderly Schizophrenics

Background: Depressive symptoms are common comorbidities in schizophrenia. However, the effect of APOE E3 on depressive symptoms has never been investigated in an aging Chinese population with schizophrenia. This cross-sectional study aimed to investigate the effects of APOE E3 on blood lipid metabolism and depressive symptoms in elderly schizophrenics in China. Methods: Three Hundred and one elderly schizophrenics (161 males, age ranges from 60 to 92 years, with an average age of 67.31 ± 6.667) were included in the study. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS). APOE gene polymorphism was determined by polymerase chain reaction (PCR). We assessed the correlations of GDS and serum low-density lipoprotein (LDL) with APOE genotypes. Results: The concentration of LDL in the Homozygous APOE E3 group was significantly higher than that in the non-homozygous APOE E3 group, while the scores of GDS of the Homozygous APOE E3 group were lower than that in the non-homozygous APOE E3 group. Using partial correlation analysis and controlling age, gender, duration of disease, and hyperlipidemia, we found that the scores of GDS were significantly correlated with LDL (r = -0.194, p = 0.016). Conclusions: APOE E3 is associated with less depressive symptoms and higher serum LDL in Chinese elderly patients with schizophrenia, and there is a negative correlation between depressive symptoms and LDL.

Apolipoprotein E and affective symptoms in mild cognitive impairment and Alzheimer's disease dementia: A systematic review and meta-analysis

OBJECTIVE

APOE status has been associated to affective symptoms in cognitively impaired subjects, with conflicting results.

METHODS

Databases CINAHL, Embase, PsychINFO and PubMed were searched for studies evaluating APOE genotype with affective symptoms in MCI and AD dementia. Symptoms were meta-analyzed separately and possible sources of heterogeneity were examined.

RESULTS

Fifty-three abstracts fulfilled the eligibility criteria. No association was found between the individual symptoms and APOE ε4 carriership or zygosity. For depression and anxiety, only pooled unadjusted estimates showed positive associations with between-study heterogeneity, which could be explained by variation in study design, setting and way of symptom assessment.

CONCLUSIONS

There is no evidence that APOE ε4 carriership or zygosity is associated with the presence of depression, anxiety, apathy, agitation, irritability or sleep disturbances in cognitively impaired subjects. Future research should shift its focus from this single polymorphism to a more integrated view of other biological factors.

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.

Neuropsychiatric signs and symptoms of Alzheimer's disease: New treatment paradigms

Neuropsychiatric symptoms (NPSs) are hallmarks of Alzheimer's disease (AD), causing substantial distress for both people with dementia and their caregivers, and contributing to early institutionalization. They are among the earliest signs and symptoms of neurocognitive disorders and incipient cognitive decline, yet are under-recognized and often challenging to treat. With this in mind, the Alzheimer's Association convened a Research Roundtable in May 2016, bringing together experts from academia, industry, and regulatory agencies to discuss the latest understanding of NPSs and review the development of therapeutics and biomarkers of NPSs in AD. This review will explore the neurobiology of NPSs in AD and specific symptoms common in AD such as psychosis, agitation, apathy, depression, and sleep disturbances. In addition, clinical trial designs for NPSs in AD and regulatory considerations will be discussed.

The prevalence of neuropsychiatric symptoms in Alzheimer's disease: Systematic review and meta-analysis

BACKGROUND

Neuropsychiatric symptoms (NPS) are being increasingly recognized as common serious problems in Alzheimer's disease (AD). However, published data on the prevalence of NPS in persons with AD are conflicting. This meta-analysis aimed to estimate the prevalence of NPS in persons with AD.

METHODS

Studies published from 1964 to September 30, 2014, were identified from PubMed and Embase database, reference lists and conference abstracts. We calculated prevalence rates and conducted meta-regression analysis with random-effects model, according to study characteristics, population demographics or condition information.

RESULTS

We identified 48 eligible articles, which provided data for 12 NPS reported in Neuropsychiatric Inventory (NPI). The most frequent NPS was apathy, with an overall prevalence of 49% (95% CI 41-57%), followed by depression, aggression, anxiety and sleep disorder, the pooled prevalence estimates of which were 42% (95% CI 37-46%), 40% (95% CI 33-46%), 39% (95% CI 32-46%) and 39% (95% CI 30-47%), respectively. The less prevalent NPS were irritability (36%, 31-41%), appetite disorder (34%, 27-41%), aberrant motor behavior (32%, 25-38%), delusion (31%, 27-35%), disinhibition (17%, 12-21%) and hallucination (16%, 13-18%). Least common was euphoria, with an overall prevalence of 7% (95% CI 5-9%).

LIMITATIONS

Several aspects, such as the quality of included studies were not always optimal and there was significant heterogeneity of prevalence estimate across studies.

CONCLUSIONS

NPS were observed to be highly prevalent in AD patients. Disease duration, age, education level, population origin and the severity of cognitive impairment had influence on the prevalence of some NPS.

Molecular neuropathogenesis of Alzheimer's disease: an interaction model stressing the central role of oxidative stress

Alzheimer's disease (AD) exhibits a complex etiology that simultaneously manifests as a complex cellular, neurobiological, molecular, anatomic-physiological and clinical entity. Other significant psychiatric conditions, such as depression and schizophrenia, may also present with complex and concurrent clinical and/or molecular phenotypes. These neuropsychiatric pathologies also originate from both environmental and genetic factors. We analyzed the molecular phenotypes of AD and discuss them with respect to the classical theories, which we integrated into mechanisms that share molecular and/or anatomical connections. Based on these mechanisms, we propose an interaction model and discuss the model in light of studies that refute or support it. Given the spectrum of AD phenotypes, we limit the scope of our discussion to a few, which facilitates concrete analysis. In addition, the study of specific, individual pathogenic phenotypes may be critical to defining the complex mechanisms leading to AD, thereby improving strategies for developing novel therapies.

Missense substitutions associated with behavioural disturbances in Alzheimer's disease (AD)

Behavioural and psychological symptoms in dementia, or BPSD, occur in the majority of Alzheimer's disease (AD) patients. They are associated with considerable patient morbidity and greater care-giver stress. There is some evidence suggesting that BPSD have a genetic component and a large number of studies have examined the association of candidate genes with these symptoms. This review provides a comprehensive summary of all the published studies investigating the association of candidate gene missense substitutions with BPSD. Missense substitutions could potentially alter protein function or render the protein non-functional, resulting in phenotypic consequences. More than 80 studies investigating the association of 8 missense substitutions in 7 genes with BPSD were identified. However, results of these studies are contradictory and do not provide firm support for these associations. Larger studies and more systematic approaches will delineate the association of missense substitutions with behavioural symptoms in AD.

Apolipoprotein E genotypes and neuropsychiatric symptoms and syndromes in late-onset Alzheimer's disease

Neuropsychiatric symptoms (NPS) in dementia, previously denominated as behavioural and psychological symptoms of dementia, are often more distressing, impairing, and costly than cognitive symptoms, representing a major health burden for older adults. These symptoms are common features of Alzheimer's disease (AD), and are one of the major risk factors for institutionalization. There is a high prevalence of neuropsychiatric disturbances in patients with AD, including depression, anxiety, apathy, psychosis, aggression, and agitation. At present, the role of the apolipoprotein E (APOE) genotypes in the development of NPS or neuropsychiatric syndromes/endophenotypes in AD patients is unclear. In this article, we summarized the findings of the studies of NPS and neuropsychiatric syndromes in AD in relation to APOE genotypes, with special attention to the possible underlying mechanisms. While some studies failed to find a significant association between the APOE polymorphism and NPS in late-onset AD, other studies reported a significant association between the APOE ɛ4 allele and an increase in agitation/aggression, hallucinations, delusions, and late-life depression or anxiety. However, current cumulative evidence coming from the few existing longitudinal studies shows no association of APOE genotypes with NPS as a whole in AD. Some negative studies that focused on the distribution of APOE genotypes between AD patients with or without NPS further emphasized the importance of sub-grouping NPS in distinct neuropsychiatric syndromes. Explanations for the variable findings in the existing studies included differences in patient populations, differences in the assessment of neuropsychiatric symptomatology, possible lack of statistical power to detect associations in the negative studies, and small sample sizes generating false positives that cannot be consistently replicated. Finally, many reviewed studies were cross-sectional, whereas it would be of paramount importance to evaluate the risk for incident NPS in relation to the APOE genotype in prospectively followed cohorts of AD patients. In fact, identifying predisposing genetic risk factors may allow us to understand the pathophysiological features of neuropsychiatric syndromes or symptoms in AD, so optimizing possible therapeutic options.

The APOE polymorphism in Alzheimer's disease patients with neuropsychiatric symptoms and syndromes

BACKGROUND

Neuropsychiatric symptoms (NPS) are a common feature of Alzheimer's disease (AD), resulting in particular AD endophenotypes. The common AD genetic risk factor apolipoprotein E (APOE) has been suggested underlying these AD endophenotypes.

METHODS

APOE genotyping, a comprehensive geriatric assessment (CGA), and Neuropsychiatric Inventory were performed on 322 consecutive older patients. Patients were divided into three groups: AD with NPS (N = 93), AD without NPS (N = 108), and, as a control group, patients with no cognitive impairment (NoCI: N = 121). Patients with NPS were further sub-divided in four groups according to the European Alzheimer's Disease Consortium (EADC) classification of neuropsychiatric syndromes in AD: hyperactive, psychotic, affective, and apathetic.

RESULTS

AD patients with NPS showed a significantly higher grade of cognitive impairment, more severity stage of dementia, more disability in the activities of daily living (ADL), and the instrumental ADL than AD patients without NPS. As expected, an higher frequency of APOE ε3/ε4 genotype was observed in patients with AD, both with and without NPS, than patients with NoCI. No difference in the distribution of APOE genotypes was found between AD patients with vs. without NPS. However, in AD patients APOE ε4-carriers, there was an increased risk of affective [odds ratio (OR): 2.34, 95% confidence interval (CI): 1.19-4.58) and apathetic (OR: 2.24,95%CI: 1.19-4.22) syndromes.

CONCLUSIONS

These findings did not suggest a significant association between APOE polymorphism and presence of NPS in AD patients. In AD patients with NPS, however, APOE ε4-carrier status was associated with an increased risk of affective and apathetic syndromes.

Neuropsychiatric Symptoms, Endophenotypes, and Syndromes in Late-Onset Alzheimer's Disease: Focus on APOE Gene

Neuropsychiatric symptoms, previously denominated as behavioural and psychological symptoms of dementia, are common features of Alzheimer's disease (AD) and are one of the major risk factors for institutionalization. At present, the role of the apolipoprotein E (APOE) gene in the development of neuropsychiatric symptoms in AD patients is unclear. In this paper, we summarized the findings of the studies of neuropsychiatric symptoms and neuropsychiatric syndromes/endophenotypes in AD in relation to APOE genotypes, with special attention to the possible underlying mechanisms. While some studies failed to find a significant association between APOE and neuropsychiatric symptoms in late-onset AD, other studies reported a significant association between the APOE ε4 allele and an increase in agitation/aggression, hallucinations, delusions, and late-life depression or anxiety. Furthermore, some negative studies that focused on the distribution of APOE genotypes between AD patients with or without neuropsychiatric symptoms further emphasized the importance of subgrouping neuropsychiatric symptoms in distinct neuropsychiatric syndromes. Explanations for the variable findings in the existing studies included differences in patient populations, differences in the assessment of neuropsychiatric symptomatology, and possible lack of statistical power to detect associations in the negative studies.

Behavioural genetics of Alzheimer's disease: a comprehensive review

Behavioural and psychological symptoms of dementia (BPSD) are present in the course of the illness in up to 90% of patients with Alzheimer's disease (AD). They are the main source of caregiver burden and one of the major factors contributing to early institutionalization. The involvement of a genetic component in BPSD aetiology seems beyond controversy, though the exact significance of particular polymorphisms is uncertain in the majority of cases. Multiple genes have been assessed for their putative influence on BPSD risk. In this paper we review the behavioural genetics of AD, particularly the importance, with respect to BPSD risk, of genes coding for apolipoprotein E and proteins involved in the process of neurotransmission: serotonin receptors, serotonin transporter, COMT, MAO-A, tryptophan hydroxylase and dopamine receptors. A general conclusion is the striking inconsistency of the findings, unsurprising in the field of psychiatric genetics. The potential reasons for such discrepancy are exhaustively discussed.

Depressive symptoms and APOE polymorphisms in an elderly population-based sample

AIM

Apolipoprotein E (APOE) has been regarded as the principal susceptibility gene linked with Alzheimer's disease, also suggesting a relationship with depression in the elderly population. Thus, the purpose was to investigate the association of APOE polymorphisms with depression in elderly adults.

METHODS

APOE polymorphisms were determined in a Mexican population-based sample older than 60 years (n=1566) using 5' exonuclease TaqMan genotyping assays.

RESULTS

The distribution of the APOE allele and genotype frequencies was similar in patients with and without depression. There was no significant association between the presence of alleles or genotypes and depression and anxiety (Short Anxiety Screening Test) considering several combinations of other features. However, patients with the APOE*4 allele presented more thinking and concentration impairment than those patients with the APOE*3 allele.

CONCLUSION

Genetic variation at the APOE gene may contribute to some depressive symptoms in late-onset depression, rather than being a specific risk factor.

Genetics of psychosis in Alzheimer's disease: a review

In and of itself, late-onset Alzheimer's disease (AD) can be a devastating illness. However, a sub-group of AD patients develop psychosis as the disease progresses. These patients have an added burden of greater cognitive impairment, higher rates of institutionalization, and higher mortality than AD patients without psychosis. While the etiopathogenesis such as psychosis in AD (AD+P) is not known, mounting evidence accrued over the past ten years indicates that AD+P represents a distinct phenotype with a genetic basis. Elucidating the genetic mechanism of AD+P is crucial if better pharmaceutical treatments are to be developed for these patients. The goal of this review is to summarize what is currently known regarding the genetic basis of psychosis in AD. Specific attention is given to familial aggregation and heritability, linkage to chromosomal loci, and associations of candidate genes of APOE and the monoamine neurotransmitter system.

Resolving the relationship between ApolipoproteinE and depression

Several studies have reported an association between the ApolipoproteinE-epsilon4 (APOE4) allele and depression among elders. However others have failed to find an association. Since APOE4 is a well recognized risk factor for Alzheimer dementia, cognitive status may represent an important confounder between APOE4 and depression. In this investigation, we examined the relationship between the ApolipoproteinE-epsilon4 allele and depression among elders accounting for cognitive status. Using a case-control design (n=1052), we investigated the association between ApolipoproteinE-epsilon4 and depression in Alzheimer disease patients (n=528) and in cognitively intact controls (n=524). We demonstrated an apparent association between the APOE4 allele and depression in the combined dataset (p=0.001) when not controlling for cognitive status. However, once stratified by the presence of Alzheimer disease, there was no association in either the Alzheimer group (p=0.290) or the cognitively intact controls (p=0.494). In this dataset there is no association between the ApolipoproteinE-epsilon4 allele and depression among those with Alzheimer disease or among cognitively intact elders. However there is a significant association between female gender and depression in the cognitively intact (p=0.003) but not among those with Alzheimer disease. Additionally, individuals with Alzheimer disease and depression had a significantly younger age of onset for their Alzheimer disease than those without depression (p=0.017).

Apolipoprotein E epsilon4 allele genotype and the effect of depressive symptoms on the risk of dementia in men: the Honolulu-Asia Aging Study

CONTEXT

The apolipoprotein E epsilon4 (APOE epsilon4) allele is a genetic risk factor for Alzheimer disease. Recently, depression has also become recognized as a risk factor for dementia. However, the possible effect of the APOE genotype on the association between depression and dementia is unexamined.

OBJECTIVE

To examine the independent and combined effects of depression and APOE epsilon4 on the risk of dementia and its subtypes.

DESIGN

The Honolulu-Asia Aging Study, a population-based prospective cohort study of Japanese American men.

SETTINGS AND PARTICIPANTS

Depressive symptoms and presence of the APOE epsilon4 allele were assessed between March 1991 and October 1993 in 1932 cognitively healthy men aged 71 to 90 years. Incident cases of dementia were diagnosed during approximately 6 years of follow-up based on neurologic assessment at 2 repeated examinations (April 1994-April 1996 and October 1997-February 1999).

MAIN OUTCOME MEASURES

Overall dementia, Alzheimer disease, and vascular dementia.

RESULTS

The interaction of depression and APOE epsilon4 was statistically significant in the analytical models. Compared with men with neither APOE epsilon4 nor depression, the risk of dementia in nondepressed men with APOE epsilon4 was not significant (hazard ratio, 1.1; 95% confidence interval [CI], 0.6-1.8); however, depressed men without APOE epsilon4 had a 1.6-fold greater risk (95% CI, 0.8-3.0), whereas depressed men with APOE epsilon4 had a 7.1-fold greater risk (95% CI, 3.0-16.7) of dementia. For subtypes, we found similar increased risks of Alzheimer disease.

CONCLUSIONS

The APOE epsilon4 status modifies the association between depressive symptoms and dementia in elderly men. Because individuals with depressive symptoms and the APOE epsilon4 allele had a markedly increased risk of dementia, one might be especially watchful for early signs of dementia in the older person with depression who is also positive for the APOE epsilon4 allele. Because this cohort includes only men, further investigation in women is required.

Psychosis in Alzheimer's Disease: Prevalence, Clinical Characteristics, Symptom Co-Morbidity, and Aetiology

Alzheimer's disease was identified almost a century ago. Cognitive morbidity (deterioration in memory, attention, language, and executive functioning) was regarded as a sufficient index for the description and diagnosis of Alzheimer's disease. Within the cognitive discourse, the importance of neuropsychiatric and neurobehavioural referents was often eschewed. Recent research studies attest to the profound impact of the non-cognitive symptoms on the quality of life of both patient and caregiver. The purpose of this article is to review studies on psychosis in Alzheimer's disease, examine its prevalence, and discuss its manifestation with reference to the association between neuropathology and psychotic disturbances. The importance of clarifying the validity of the construct ‘psychosis in Alzheimer's disease’, the specificity of symptoms, and the phenomenology of subtypes with their distinct clinical and biological associations is addressed.

The effect of the apolipoprotein E gene polymorphisms and haplotypes on behavioural and psychological symptoms in probable Alzheimer's disease

BACKGROUND

Patients with Alzheimer's disease and dementia commonly suffer from behavioural and psychological symptoms of dementia (BPSD). A genetic component to BPSD development in Alzheimer's disease has been demonstrated. Several studies have investigated whether the exon 4 epsilon2/epsilon3/epsilon4 haplotype of the apolipoprotein E (APOE) gene is associated with BPSD, with variable results.

OBJECTIVE

We investigated the exon 4 polymorphisms and extended this study to include promoter polymorphisms and the resultant haplotypes across the gene.

METHODS

Our large independent cohort of 388 patients with longitudinal measures of BPSD assessed by the Neuropsychiatric Inventory was used to analyse whether any of these variants were associated with the presence of BPSD.

RESULTS

We revealed several significant relationships before correction for multiple testing. The exon 4 haplotype was associated with hallucinations and anxiety, A-491T with irritability, T-427C with agitation/aggression and appetite disturbances, and T-219C with depression. Haplotype analyses of all variants did not reveal any statistically significant findings.

CONCLUSIONS

Our data and a review of previous studies showed a diversity of relationships, suggesting that these findings might be due to chance and so collectively do not support a role for the APOE gene in BPSD.

Apolipoprotein E epsilon4 allele increases risk for psychotic symptoms in Alzheimer's disease

The apolipoprotein E (ApoE) epsilon4 allele is a well-documented genetic risk factor for sporadic Alzheimer's disease (AD). Its association with psychopathology among AD patients has been the subject of discrepant reports. We aimed to determine whether ApoE epsilon4+ and epsilon4- AD patients exhibit a different risk profile for psychotic symptoms and other behavioral disturbances. The Neuropsychiatric Inventory (NPI) was administered to determine the frequency and severity of psychotic and other behavioral symptoms in a sample of n=266 AD patients who had been genotyped for ApoE. Multiple logistic regression models were used to calculate the association between the ApoE epsilon4 allele and the presence of psychotic symptoms (delusions or hallucinations). Exploratory analyses were also conducted to determine the impact of disease severity on epsilon4 effects and to examine the association between epsilon4 and other behavioral symptoms. ApoE epsilon4 was significantly associated with psychotic symptoms (odds ratio (OR)=1.87, 95% CI=1.07-3.29, P=0.029), adjusting for age, sex, education, and MMSE score. More stringent definitions of clinically significant psychosis yielded similar results. Exploratory analyses suggested that this effect accrued specifically from patients with severe-stage AD and primarily from an association between epsilon4 and delusions. The epsilon4 allele did not appear to influence the development of most other behavioral symptoms in our sample. In conclusion, AD patients who carry the ApoE epsilon4 allele are at greater risk than noncarriers for developing psychotic symptoms, particularly as the severity of their dementia progresses.

The neurobiology of neuropsychiatric syndromes in dementia

PURPOSE OF REVIEW

Neuropsychiatric disturbances in dementia are prevalent, and research is uncovering their neurobiological correlates.

RECENT FINDINGS

Late-onset depression appears to be associated with Alzheimer's disease pathology at autopsy, and lifetime depression episodes may worsen Alzheimer's disease pathology in the hippocampus. Vascular disease and elevated homocysteine increase risk for both late-onset depression and Alzheimer's disease and may partly mediate their relationship. Monoamine changes are robust finding in Alzheimer's disease and may account for many observed depression symptoms. Risk of psychosis of Alzheimer's disease appears to be increased by several genes also implicated in schizophrenia (e.g., catechol-O-methyltransferase, neuregulin-1). Psychosis in dementia with Lewy bodies appears to be related to cholinergic deficits. Alzheimer's disease is associated with changes in the circadian sleep-wake cycles, including decreased night-time melatonin. Sleep apnea may be related to apolipoprotein E genotype and impact cognition in Alzheimer's disease. Rapid eye movement sleep behavior disorder is intricately related to synucleinopathies, such as dementia with Lewy bodies, but synuclein changes may not totally explain this relationship.

SUMMARY

Neuropsychiatric disturbances are a core feature of dementia and worsen many clinical outcomes. Among the most validated syndromes are depression, psychosis, and sleep disturbance of Alzheimer's disease. Neuropathology, neuroimaging, and genetic studies increasingly provide insight into the origins of these psychiatric symptoms in dementia.

Association of depression with Alzheimer's disease and vascular dementia in an elderly Arab population of Wadi-Ara, Israel

OBJECTIVES

Because dementia and depression share common risk factors, we investigated risk factors for depression in Arab subjects with Alzheimer's disease (AD) and vascular dementia (VaD).

METHODS

In a cross-sectional population-based study, we conducted a door-to-door survey of all adults over age 60 in an Arab community of rural Israel. We conducted interviews, gave questionnaires, and collected DNA blood specimens for determination of ApoE genotype.

RESULTS

Of the 823 individuals in this naturalistic sample, 168 had dementia of Alzheimer's type (DAT) and 49 had VaD. Vascular risk factors, including the ApoE-epsilon4 allele, were more prevalent among VaD than DAT subjects. Depressive symptoms were present in 57% of DAT patients and 86% of VaD patients. Depressed DAT individuals had a greater history of ischemic cardiovascular or cerebrovascular (CV/CBV) disease than non-depressed DAT subjects, but depressed DAT subjects were less likely to have the ApoE-epsilon4 allele. Within the VaD group, there was no difference in the distribution of cardiovascular risk factors in individuals with and without depressive symptoms, and ApoE-epsilon4 was more prevalent among subjects with depressive symptoms.

CONCLUSIONS

Depressive symptomatology is prevalent among subjects with dementias in this Arab community. History of CV/CBV is associated with the presence of depressive symptoms in DAT. Further studies are needed to clarify the role of ApoE in depression onset in different ethnic groups with DAT.

Delusion symptoms are associated with ApoE epsilon4 allelic variant at the early stage of Alzheimer's disease with late onset

Alzheimer's disease (AD) is a neurodegenerative disorder with mixed cognitive and behavioural clinical manifestations. The possession of apolipoprotein-E (ApoE) epsilon4 allelic variant is one of the most important risk factors for developing late-onset AD (LOAD). In this study we analysed the relationship between the entire range of behavioural symptoms, cognitive deficit, and sociodemographic characteristics and ApoE epsilon4 allele possession with multivariate logistic regression models in LOAD patients. Patients included (n = 171) were consecutively admitted in a memory clinic for the first diagnostic visit. Levels of behaviour and cognition within the last month were assessed by the Neuropsychiatric Inventory and Mini Mental State Examination. Presence of clinically significant psychosis, delusions and hallucinations at the early stage of the illness, from the onset to the first visit, was measured with diagnostic criteria. ApoE epsilon4 allele possession was associated with increased levels of delusions within the last month from the first visit (OR 1.23; 95% CI 1.01-1.50; P < 0.05) and with the presence of categorical delusions at the early stage until the first visit (OR 3.11; 95% CI 1.21-8.01; P < 0.02). In this study, which considers the entire range of behavioural expressions in LOAD patients at the early stage of the illness, the relationship between behaviour and ApoE epsilon4 allele is confirmed for delusions only.

Protective effect of the apo epsilon2 allele in major depressive disorder in Taiwanese

OBJECTIVE

Major depression is an important comorbidity in Alzheimer's disease, which is definitely associated with the apolipoprotein E (apo E) polymorphism. The aim of this study was to explore the role of the different apo E polymorphisms in major depressive disorder (MDD) in a Taiwanese population.

METHOD

We examined apo E genotypes in 273 Taiwanese patients with MDD and 429 healthy community controls, and compared their polymorphism distribution.

RESULTS

The allelic frequency of apo epsilon2 was significantly lower in patients with MDD than in the controls, whereas no significant difference in apo epsilon4 allelic frequency between these two groups was found.

CONCLUSION

The apo epsilon4 allele was not associated with MDD in this study. However, the finding of a lower frequency of the apo epsilon2 allele in MDD could lead to the conclusion that the apo epsilon2 allele likely provides a protective effect against MDD in the Taiwanese population.

Association analysis of apolipoprotein E genotype and risk of depressive symptoms in Alzheimer's disease

OBJECTIVES

Behavioural and psychological symptoms of dementia (BPSD) are potent predictors of carer distress and admission to institutional care. In Alzheimer's disease (AD), depressive symptoms are one of the most common complaints affecting around 50% of all patients. There is speculation these symptoms result from known genetic risk factors for AD, therefore we investigated the role of apolipoprotein E epsilon4 in the aetiology of depression in AD.

METHODS

In this well-characterised cohort (n = 404) from the relatively genetically homogeneous Northern Ireland population, we tested the hypothesis that genetic variants of apolipoprotein E influence the risk for depressive symptoms in AD patients using the Neuropsychiatric Inventory (NPI-D) to determine the presence of depressive symptoms during the dementing illness.

RESULTS

A total of 55% of patients exhibited a history of depression/dysphoria during the course of the illness as gathered by the NPI-D questionnaire. Forty-six percent were suffering from depression/dysphoria when the analysis was restricted to the month prior to interview. No statistically significant association between genotypes or alleles of apolipoprotein E and depression/dysphoria in AD was observed, nor was any association noted between the presence of severe symptoms and genotypes/alleles of apolipoprotein E.

CONCLUSIONS

These results suggest apolipoprotein E genotype creates no additional risk for depressive symptoms in AD.

Regional cerebral metabolism in early Alzheimer's disease with clinically significant apathy or depression

BACKGROUND

Alzheimer's disease (AD) is clinically characterized by cognitive impairment and behavioral disturbances. The aim of the study was to identify regional alterations in brain function associated with neuropsychiatric symptoms in early AD.

METHODS

Patients underwent measures of cerebral glucose metabolism applying positron emission tomography (PET) and (18)F-fluorodeoxyglucose. Neuropsychiatric symptoms were assessed using the Neuropsychiatric Inventory (NPI). Positron emission tomography images of patients suffering a neuropsychiatric symptom of clinical significance (NPI subscore for a specific item >/=4 points) were compared with the images of patients without the specific symptom under study (NPI subscore for a specific item = 0 points).

RESULTS

A total of 53 patients with AD (Mini-Mental State Examination [MMSE] 22.5 +/- 2.94 points) entered the study. Of all symptoms, apathy and depression were most frequently encountered. The patient group with apathy (n = 17) revealed significant decreases in left orbitofrontal regions when compared with patients free of apathy. Depression of clinical significance (n = 10) was associated with hypometabolism in dorsolateral prefrontal regions.

CONCLUSIONS

These findings support the notion that different functional circuits underlie apathy and depression in early AD.

The evolving role of genomics in shaping care for persons with dementia

Alzheimer's disease and other chronic dementing conditions remain formidable challenges for individuals, their families, and health care providers. In addition to the challenges inherent in the sheer numbers affected, the complex and relatively unpredictable progression of these disorders complicates the delivery of interventions for health care providers. Identifying genetic and environmental etiologic factors and understanding their relationship to the natural history of dementia brings health care providers closer to more effective pharmacologic treatments and perhaps cure. In the meantime, genomics research brings professional nurses closer to providing more specific, perhaps individualized, anticipatory guidance and to providing nonpharmacologic interventions in a genotype-directed way to patients with chronic dementing conditions. The emergence of a genomics-based health care environment presents an opportunity and a challenge for gerontological nurse clinicians, educators, and researchers--an opportunity to evolve practice toward a higher level of specificity and effectiveness and a challenge to do so in a equitable and sensitive manner that improves health and quality of life for all served.

Delusions and hallucinations in Alzheimer's disease: review of the brain decade

The authors reviewed studies published from 1990 to 2001 that address the epidemiology, phenomenology, course, etiology, assessment, and treatment of delusions and hallucinations in Alzheimer's disease. The prevalence of delusions in Alzheimer's disease patients ranged from 16% to 70% (median=36.5%) in the reviewed reports, and the prevalence of hallucinations ranged from 4% to 76% (median=23%). Delusions and hallucinations tended to persist over time, tended to recur often during the course of Alzheimer's disease, and were associated with sociodemographic and clinical correlates that differed from one study to another and with substantial consequences such as functional impairment and aggression. Psychosocial methods and both typical and atypical antipsychotics are effective in the treatment of delusions and hallucinations in Alzheimer's disease.

HSP70-2 (HSPA1B) is associated with noncognitive symptoms in late-onset Alzheimer's disease

Neuropsychiatric manifestations are common in Alzheimer's disease (AD) and their phenotypic expression might be related to physiopathological and genetic causes. Multiple studies have implicated oxidative stress to the pathogenesis and possible etiology of AD. One of the mechanisms to protect cells from oxidative stress is the expression of heat-shock proteins (HSP). HSPA1B (alternatively known as HSP70-2) has been related to AD pathophysiology. In the present analysis, 77 AD patients were classified according to their cognitive status with the Neuropsychiatric Inventory and were genotyped for an insertion/deletion (A1/A2) polymorphism. The A2 allele conferred a significant increase of psychiatric morbidity in an allele-dose manner (P < .05). This pattern can be attributed to all AD stages and the severity of the behavioral disturbances was higher for those patients carrying one or two A2 alleles. These results indicate a possible association between the A2 allele and an overexpression of noncognitive symptoms in AD.

Depression in Alzheimer's disease: heterogeneity and related issues

Several studies have demonstrated that the great majority of Alzheimer's disease (AD) patients suffer "noncognitive" neuropsychiatric symptoms. Depression is one of the most frequent neuropsychiatric comorbidities of AD. Affecting up to 50% of AD patients, depression in AD is associated with serious negative consequences for patients and their caregivers. Yet available studies on the natural course, etiology, and treatment of depression in AD have been few and equivocal. Heterogeneity in research methodology and etiology of depression in AD might have contributed to inconsistent findings across studies. Recently, the National Institute of Mental Health (NIMH) convened the Depression of Alzheimer's Disease Workgroup, which proposed provisional diagnostic criteria for depression of Alzheimer's Disease (NIMH-dAD). These criteria may provide a framework for future studies to clarify the unresolved issues in nosology, etiology, and treatment of depression in AD. A longitudinal cohort study of depression in incident AD cases may provide further syndrome refinement that would facilitate investigation of the etiology and treatment of depression in AD.

Psychotic symptoms in Alzheimer disease: evidence for a distinct phenotype

Though efforts to identify the genetic etiology of Alzheimer disease (AD) have made substantial progress, to date only some of the genes contributing to AD risk have been identified. Utilization of more etiologically homogeneous subphenotypes represents one strategy to facilitate the identification of novel risk genes in complex disorders. In this review, we evaluate the hypothesis that psychotic symptoms, such as delusions and hallucinations, define a suitable subphenotype in AD patients for gene-mapping efforts. Psychotic symptoms occur in 40-60% of patients with AD and are associated with more severe cognitive deficits and a more rapidly deteriorating course. The presence of psychotic symptoms in AD confers increased risk of similar symptoms to affected siblings. Candidate gene association analyses and initial linkage analysis have yielded significant results. We discuss possible genetic models of psychotic symptoms in AD, and suggest strategies for further investigation. Identification of such genetic factors may facilitate gene-mapping studies for both AD and idiopathic psychoses.

Lack of association between the apolipoprotein E genotype and depression in Alzheimer's disease

The epsilon4 allele of apolipoprotein (apo E) is one of the risk factors for late-onset Alzheimer's disease (AD). We evaluated the association between apo E genotypes and depression in patients with AD. A psychiatrist interviewed all patients and their caregivers for depression using a Chinese version of the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, and for the severity of depression using the Hamilton Depression Rating Scale (HDRS). Twenty-five of the 149 patients with AD were diagnosed with depressive disorders. The numbers of patients in each apo E genotype were 10 in epsilon2/3, 2 in epsilon2/4, 74 in epsilon3/3, 46 in epsilon3/4, and 17 in epsilon4/4. We did not find an association between depression and the presence or absence of the epsilon4 or epsilon2 allele. The HDRS scores were not different in patients with AD with the epsilon4 or epsilon2 allele or in those patients without them. Our study did not find an association between depression and the apo E epsilon4 or epsilon2 allele in AD.

Apolipoprotein E and alpha-1-antichymotrypsin genotypes do not predict time to psychosis in Alzheimer's disease

Psychotic symptoms occurring in Alzheimer's disease (AD + psychosis, AD + P) are a marker for a more rapidly deteriorating phenotype. We have developed a polygenic model of AD + P risk, conditioned on the presence of AD. Whether risk genes for AD itself contribute to AD + P risk is not established, although our model predicts they will not. The most important identified genetic determinant of sporadic, late-onset AD is the apolipoprotein E epsilon 4 allele (APOE4). The effect of APOE4 on AD phenotype is to reduce the age of onset of AD. Prior studies examining the association of APOE4 with AD + P have reported conflicting results. However, no prior studies have examined if APOE4 reduces time to onset of psychosis in AD. The objective of this study was to examine the effect of APOE4 and alpha1-antichymotrypsin/AA (ACT/AA) genotypes on time to psychosis onset in subjects with AD. A longitudinal study of psychosis incidence in 316 subjects with AD with no history of current or prior psychotic symptoms at entry was undertaken. APOE and ACT genotyping was conducted per established protocols. Data were analyzed by survival analysis and Cox proportional hazards models. There were no significant associations of APOE or ACT genotypes with time to psychosis onset and no significant interaction of these genotypes with time to psychosis onset. There remained no significant associations after covarying for age, age of AD onset, degree of cognitive impairment, gender, race, and education. This is the first study to examine the genetic prediction of psychosis onset in AD. The findings support the hypothesis that these two genetic determinants of AD risk do not contribute to the risk of development of psychotic symptoms in AD.

Association between the APOE genotype and psychopathologic symptoms in Alzheimer's disease

BACKGROUND

Psychiatric symptoms occur frequently in the course of AD, are a frequent contributor to institutionalization, predict cognitive decline and death, and often require treatment with psychotropic medications. Previous studies investigating the association between APOE genotype and psychiatric symptomatology in AD have reported contradictory results.

OBJECTIVE

To determine whether APOE genotype predicts incident psychiatric symptomatology in patients with AD.

METHODS

Eighty-seven patients with AD at early stages and no psychiatric history were followed semiannually for up to 9.3 years (mean 5.5 years) for development of delusions, illusions, hallucinations, behavioral symptoms, and depression. Cox proportional hazards models were used to examine the relative risk for incident psychiatric symptomatology (outcome) in relation to APOE genotype (predictor).

RESULTS

The presence of one epsilon4 allele carried a 2.5-fold risk, whereas the presence of two epsilon4 alleles carried a 5.6-fold risk for development of delusions. The associations remained significant even when age, ethnicity, sex, education, duration of disease, and cognitive and functional performance were controlled for. The presence of two epsilon4 alleles was associated with reduced risk for developing hallucinations in the adjusted analysis only. No significant associations were detected between APOE genotype and the incidence of illusions, behavioral symptoms, or depression.

CONCLUSION

The presence of one or more epsilon4 alleles is a significant predictor for the incidence of delusions in the course of AD.

Negative symptoms, depression and Alzheimer's disease

OBJECTIVES

To apply the negative symptoms (NS) concept used in schizophrenia to patients with AD, to compare the results with the frontal lobe perfusion in ethyl cysteinate dimmer (ECD) single-photon emission computed tomography (SPECT) and with the apolipoprotein E genotype.

METHOD

32 patients with a diagnosis of probable AD were assessed by the Positive and Negative Symptoms Scale (PANSS-N), the Montgomery and Asberg Depression Scale (MADRS), the NeuroPsychiatric Inventory (NPI), and the Mini-Mental Status Examination (MMSE). Each patient underwent ECD SPECT and APO E genotyping. PANSS-N, MADRS, NPI, and MMSE were administered to 19 normal elderly control subjects.

RESULTS

The mean PANSS-N score for AD patients (20.56, SD: 8, range: 7-40) was significantly higher (p < 0.001) than that of controls (7, SD: 0). MADRS scores were not significantly different (p = 0.75) between AD patients (9.03, SD: 6.14, range: 0-25) and controls (6.2, SD: 3.61, range: 1-15). The NPI apathy score (0-12) was correlated with PANSS-N (p < 0.001). Correlation between prominent frontal hypoperfusion (six cases) and NS was at the limit of significance. No relation was found between epsilon E4 and NS.

CONCLUSION

This consideration is important in distinguishing between depression and AD.

Predictors of severity of behavioral disturbance among community-dwelling elderly individuals with Alzheimer's disease: a 6-year follow-up study

To clarify which baseline factors, including apolipoprotein E (ApoE) genotyping and caregiver characteristics, predict the future severity of behavioral disturbance among community-dwelling elderly with Alzheimer's disease (AD), we conducted a longitudinal study for up to 6 years. Fourteen kinds of behavioral disturbance were evaluated. Analyses using data from 62 subjects with at least three annual assessments revealed that the baseline severity of behavioral disturbance was the strongest predictor of future severity, followed by baseline stage of dementia or use of support services. However, ApoE epsilon4 had only a marginal effect at most. The behavioral disturbances examined in the present study appear to be innately determined phenomena rather than merely representing stages of AD.

Apolipoprotein E genotype and noncognitive symptoms in Alzheimer's disease

BACKGROUND

The apolipoprotein E (ApoE) epsilon 4 allele confers significant risk for Alzheimer's disease and is associated with a greater amyloid burden in the brain. Future treatments may target molecular mechanisms associated with this allele, and it is important to define any phenotypic characteristics that correspond to this genotype. We sought to clarify the relationship between ApoE status and noncognitive symptoms in Alzheimer's disease patients.

METHODS

Possible and probable Alzheimer's disease patients from a clinical trial (n = 605) were assessed with the 10-item Neuropsychiatric Inventory cross-sectionally prior to treatment, and their ApoE genotype was determined. Among the population studied, the following numbers with specific genotypes were studied: 23-2/3, 17-2/4, 209-3/3, 288-3/4, 68-4/4.

RESULTS

When correlations were controlled for the patient's level of cognitive impairment, there was no relationship between epsilon 4 dose and any of the 10 noncognitive symptoms assessed, including psychosis, mood changes, and personality alterations.

CONCLUSIONS

Among patients with comparable disease severity, the epsilon 4 allele does not confer additional psychiatric morbidity.

Apolipoprotein E regulatory region genotype in schizophrenia

Clinical observations indicate that a proportion of patients with schizophrenia experience cognitive impairment, which suggests that a neurodegenerative basis might be involved in the etiology of schizophrenia. Apolipoprotein E (ApoE), which has been confirmed to be genetically associated with Alzheimer's disease, is thus highlighted as a candidate gene for schizophrenia. Recently, novel functional polymorphisms in the ApoE transcriptional regulatory region have been found. To investigate whether these polymorphisms are associated with the risk of schizophrenia, we genotyped 144 patients with schizophrenia and 134 controls for two polymorphisms (-491A/T and -219G/T). No significant positive associations between both polymorphisms and schizophrenia were observed. Our findings exclude the regulatory region of the ApoE gene as a locus that might confer increased susceptibility to schizophrenia.