Behavioural pathology in Alzheimer's disease with special reference to apolipoprotein E genotype

Malnutrition and neuropsychiatric symptoms in dementia: the Cache County Dementia Progression Study

OBJECTIVES

Among people with dementia, poor nutritional status has been associated with worse cognitive and functional decline, but few studies have examined its association with neuropsychiatric symptoms (NPS). We examined this topic in a population-based sample of persons with dementia.

DESIGN

Longitudinal, observational cohort study.

SETTING

Community.

PARTICIPANTS

Two hundred ninety-two persons with dementia (71.9% Alzheimer's disease, 56.2% women) were followed up to 6 years.

MEASUREMENTS

We used a modified Mini-Nutritional Assessment (mMNA) and the Neuropsychiatric Inventory (NPI) to evaluate nutritional status and NPS, respectively. Individual linear mixed effects models examined the associations between time-varying mMNA total score or clinical categories (malnourishment, risk for malnourishment, or well-nourished) and NPI total score (excluding appetite domain) or NPI individual domain or cluster (e.g. psychosis) scores. Covariates tested were dementia onset age, type, and duration, medical comorbidities, sex, apolipoprotein E (APOE) genotype, and education.

RESULTS

Compared to the well-nourished, those at risk for malnourishment and those malnourished had higher total NPI scores [b (95% CI) = 1.76 (0.04, 3.48) or 3.20 (0.62, 5.78), respectively], controlling for significant covariates. Higher mMNA total score (better nutritional status) was associated with lower total NPI [b (95% CI) = -0.58 (-0.86, -0.29)] and lower domain scores for psychosis [b (95% CI) = -0.08 (-0.16, .004)], depression [b (95% CI = -0.11 (-0.16, -0.05], and apathy [b (95% CI = -0.19 (-0.28, -0.11)].

CONCLUSIONS

Worse nutritional status is associated with more severe NPS. Dietary or behavioral interventions to prevent malnutrition may be beneficial for persons with dementia.

Education level is associated with neuropsychiatric symptoms in patients with amnestic-mild cognitive impairment

BACKGROUND

We examined differences in the severity of neuropsychiatric symptom (NPS) subsyndromes according to education level among patients with amnestic-mild cognitive impairment (a-MCI) with the aim of identifying patient demographics related to NPS subsyndromes.

METHODS

Overall, 140 patients with a-MCI were included. We divided the patients into three groups according to their educational level (primary education, middle education, and high education) and compared their demographics. To explore the severity of NPS subsyndromes according to educational level, we used the Neuropsychiatric Inventory (NPI) after adjustments for the Mini-Mental State Examination (MMSE) score. Finally, NPS subsyndromes that were identified as being related to educational level were further explored using a general linear model (GLM).

RESULTS

Significant differences in several demographics were observed among the three groups. Among the NPS subsyndromes, the scores for aggressiveness were significantly higher in the primary and high education groups than in the middle education group, while the apathy/eating problem scores were significantly higher in the primary education group than in the other groups. The GLM analyses showed that aggressiveness was related to marital status and the Zarit Caregiver Burden Interview (ZBI-J) score, while apathy/eating problems were related to the instrumental activities of daily living (IADL) percentage, the ZBI-J score, and the education level in years.

CONCLUSIONS

Among NPS subsyndromes, aggressiveness and apathy/eating problems differed according to education level in patients with a-MCI. A GLM analysis suggested that not only education level, but also various other factors should be considered when determining the need for NPS interventions.

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.

The evolution of personality in patients with mild cognitive impairment

AIMS

To describe personality traits and their changes in mild cognitive impairment (MCI) and control subjects.

METHODS

Sixty-three MCI and 90 control subjects were asked to describe their current personality traits by the Structured Interview for the Five-Factor Model (SIFFM). For each subject, a close relative retrospectively assessed these descriptions both as to the previous and current personality traits, using the Revised NEO Personality Inventory, Form R (NEO-PI-R).

RESULTS

Self-assessed MCI subjects reported significantly lower scores in the openness dimension than control subjects [F(1, 150) = 9.84, p = 0.002, ηp(2) = 0.06]. In current observer ratings, MCI subjects had higher scores on neuroticism [F(1, 137) = 7.55, p = 0.007, ηp(2) = 0.05] and lower ones on extraversion [F(1, 137) = 6.40, p = 0.013, ηp(2) = 0.04], openness [F(1, 137) = 9.93, p = 0.002, ηp(2) = 0.07], agreeableness [F(1, 137) = 10.18, p = 0.002, ηp(2) = 0.07] and conscientiousness [F(1, 137) = 25.96, p < 0.001, ηp(2) = 0.16]. Previous personality traits discriminated the groups as previous openness [odds ratio (OR) = 0.97, 95% confidence interval (CI) = 0.95-0.99, p = 0.014] and conscientiousness (OR = 0.96, 95% CI 0.94-0.98, p = 0.001) were negatively related to MCI group membership. In MCI subjects, conscientiousness [F(1, 137) = 19.20, p < 0.001, ηp(2) = 0.12] and extraversion [F(1, 137) = 22.27, p < 0.001, ηp(2) = 0.14] decreased between previous and current evaluations and neuroticism increased [F(1, 137) = 22.23, p < 0.001, ηp(2) = 0.14], whereas no significant change was found in control subjects.

CONCLUSIONS

MCI subjects undergo significant personality changes. Thus, personality assessment may aid the early detection of dementia.

Risk factors for behavioral abnormalities in mild cognitive impairment and mild Alzheimer's disease

BACKGROUND

Behavioral symptoms are common in both mild cognitive impairment (MCI) and Alzheimer's disease (AD).

METHODS

We analyzed the Neuropsychiatric Inventory Questionnaire data of 3,456 MCI and 2,641 mild AD National Alzheimer's Coordinating Center database participants. Using factor analysis and logistic regression we estimated the effects of age, sex, race, education, Mini-Mental State Examination, functional impairment, marital status and family history on the presence of behavioral symptoms. We also compared the observed prevalence of behavioral symptoms between amnestic and nonamnestic MCI.

RESULTS

Four factors were identified: affective behaviors (depression, apathy and anxiety); distress/tension behaviors (irritability and agitation); impulse control behaviors (disinhibition, elation and aberrant motor behavior), and psychotic behaviors (delusions and hallucinations). Male gender was significantly associated with all factors. Younger age was associated with a higher prevalence of distress/tension, impulse control and psychotic behaviors. Being married was protective against psychotic behaviors. Lower education was associated with the presence of distress/tension behaviors. Caucasians showed a higher prevalence of affective behaviors. Functional impairment was strongly associated with all behavioral abnormalities. Amnestic MCI patients had more elation and agitation relative to nonamnestic MCI patients.

CONCLUSIONS

Younger age, male gender and greater functional impairment were associated with higher overall presence of behavioral abnormalities in MCI and mild AD. Marital status, lower education and race had an effect on selected behaviors.

Vascular factors are associated with the severity of the neuropsychiatric symptoms in Alzheimer's disease

INTRODUCTION

The purpose of this study is to determine whether vascular risk factors are associated with severity of neuropsychiatric symptoms (NPS) in patients of Alzheimer's dementia.

METHODS

We reviewed medical records of 162 patients with Alzheimer's dementia. The NPS were assessed using the Neuropsychiatric Inventory (NPI). Hypertension and cardiovascular events were detected through detailed history taking. Diabetes mellitus and hyperlipidemia were uncovered through laboratory test. The asymptomatic stroke and white matter hyperintensities (WMH) were defined by magnetic resonance imaging. Partial correlation analysis was used.

RESULTS

Hypertension was correlated with the severity of apathy (r = 0.231, p = 0.015). The asymptomatic stroke was related to the severity of depression (r = 0.255, p = 0.007). The remaining vascular factors were not significant.

CONCLUSION

Presence of hypertension and asymptomatic stroke are related with the severity of apathy and depression in Alzheimer's dementia.

Apolipoprotein E ε4 status modifies the effects of sex hormones on neuropsychiatric symptoms of Alzheimer's disease

BACKGROUND

Studies on the associations between sex hormones and multiple neuropsychiatric symptoms of Alzheimer's disease (AD) are lacking. Apolipoprotein E (APOE) ε4 status may modify the effects of sex hormones on neuropsychiatric symptoms.

METHODS

A total of 86 male and 87 female AD patients participated in the present study. The adjusted associations between symptoms on the Neuropsychiatric Inventory and serum levels of estradiol (total, bioavailable) and testosterone (total, bioavailable) were analyzed.

RESULTS

Agitation/aggression was negatively associated with quartiles of bioavailable estradiol among male patients, and positively associated with testosterone levels among female patients. The modifying effects of APOE genotype only existed in female patients. Those females with higher levels of estradiol and the ε4 allele had higher odds of agitation/aggression. Furthermore, the testosterone × APOE ε4 status interaction was positively associated with hallucinations in female patients.

CONCLUSION

There were sex-specific effects of sex hormones on agitation/aggression in AD. Sex hormones and APOE ε4 status synergistically influence some neuropsychiatric symptoms among female but not male AD patients.

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.

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.

Apolipoprotein epsilon4 status is associated with behavioral symptoms in nursing home residents with dementia

BACKGROUND

While the relationship of apolipoprotein E (APOE) to behavioral symptoms of dementia (BSD) has been studied in community-dwelling persons with AD, it has received limited attention within the nursing home (NH) population. The aim of this study was to examine the association between APOE genotype and BSD in NH residents using direct observation.

METHODS

Thirty-six participants, aged 71-102 years, were compared using a non-randomized two-group design with continuous measures. APOE genotype was obtained by buccal swab. BSD, including restlessness, escape restraint, tapping and banging, searching and wandering, pacing and walking, and vocalization, were measured using the Modified Agitated Behavior Rating Scale. Participants were observed every 20 minutes for 12 hours per day for five days. Each participant's mean behavior scores were compared according to the presence or absence of the APOE epsilon4 allele.

RESULTS

Resident characteristics included a mean MMSE of 10.44 indicating moderate to severe dementia and a mean of 3.44 medical co-morbidities. Fifty-six percent of the participants had one epsilon4 allele. A significant difference was found between APOE epsilon4+/4- and mean behavioral scores (F(1,31)) = 4.40, p = 0.04). Restlessness was significantly inversely correlated with MMSE (r = -0.367, p = 0.03), but not APOE genotype. There was no significant correlation between proxy reporting and direct observation (r = 0.257, p = 0.13).

CONCLUSION

Findings indicate that the presence of the APOE epsilon4+ genotype increases the risk for BSD in NH residents with dementia. Direct observation proved a more accurate estimate of BSD than proxy report.

ApoE alleles, depression and positive affect in multiple sclerosis

BACKGROUND

The role of apolipoprotein E (ApoE) alleles has received recent attention in depressive disorders, the ApoE epsilon4 conferring greater risk for poorer outcomes, and the ApoE epsilon2 allele providing some protective effects. Depression is common in multiple sclerosis (MS) and the role of ApoE alleles is unknown.

AIMS

To evaluate ApoE alleles in relation to symptoms of depression in a cohort of patients with MS participating in the Sonya Slifka Longitudinal Multiple Sclerosis Study (Slifka Study). To examine risk and protection, depressed mood and positive affect were each investigated with respect to the ApoE epsilon4 and ApoE epsilon2 alleles, respectively.

RESULTS

Of the total 101 participants, 22.8% were ApoE epsilon2 carriers and 21.8% were ApoE epsilon4 carriers. Hierarchical linear regression analyses suggested that after controlling for demographics, disease duration, and disability, ApoE epsilon2 significantly predicted increased positive affect (R2Delta=0.05, F(1,94)=5.44, P=0.02) and was associated with decreased severity of depressive symptoms, although this did not reach statistical significance (R2Delta=0.03, F(1,94)=3.44, P=0.06). ApoE epsilon4 did not significantly predict depression status.

CONCLUSION

The presence of the ApoE epsilon2 allele in this study is suggested to be protective against depressive symptoms in our subsample of patients recruited from the Slifka Study. These findings are consistent with reports in psychiatric populations linking ApoE epsilon2 with decreased incidence of depressive disorders. Further investigation would be warranted to understand the role of ApoE genotypes and risk for depressive symptoms.

Pharmacogenomic Biomarkers in Neuropsychiatry: The Path to Personalized Medicine in Mental Disorders

Neuropsychiatric disorders and dementia represent a major cause of disability and high cost in developed societies. Most disorders of the central nervous system (CNS) share some common features, such as a genomic background in which hundreds of genes might be involved, genome-environment interactions, complex pathogenic pathways, poor therapeutic outcomes, and chronic disability.

Recent advances in genomic medicine can contribute to accelerate our understanding on the pathogenesis of CNS disorders, improve diagnostic accuracy with the introduction of novel biomarkers, and personalize therapeutics with the incorporation of pharmacogenetic and pharmacogenomic procedures to drug development and clinical practice.

The pharmacological treatment of CNS disorders, in general, accounts for 10–20% of direct costs, and less than 30–40% of the patients are moderate responders to conventional drugs, some of which may cause important adverse drugs reactions (ADRs). Pharmacogenetic and pharmacogenomic factors may account for 60–90% of drug variability in drug disposition and pharmacodynamics. Approximately 60–80% of CNS drugs are metabolized via enzymes of the CYP gene superfamily; 18% of neuroleptics are major substrates of CYP1A2 enzymes, 40% of CYP2D6, and 23% of CYP3A4; 24% of antidepressants are major substrates of CYP1A2 enzymes, 5% of CYP2B6, 38% of CYP2C19, 85% of CYP2D6, and 38% of CYP3A4; 7% of benzodiazepines are major substrates of CYP2C19 enzymes, 20% of CYP2D6, and 95% of

CYP3A4. About 10–20% of Caucasians are carriers of defective CYP2D6 polymorphic variants that alter the metabolism of many psychotropic agents. Other 100 genes participate in the efficacy and safety of psychotropic drugs. The incorporation of pharmacogenetic/ pharmacogenomic protocols to CNS research and clinical practice can foster therapeutics optimization by helping to develop cost-effective pharmaceuticals and improving drug efficacy and safety. To achieve this goal several measures have to be taken, including: (a) educate physicians and the public on the use of genetic/ genomic screening in the daily clinical practice; (b) standardize genetic testing for major categories of drugs; (c) validate pharmacogenetic and pharmacogenomic procedures according to drug category and pathology; (d) regulate ethical, social, and economic issues; and (e) incorporate pharmacogenetic and pharmacogenomic procedures to both drugs in development and drugs in the market to optimize therapeutics.

APOE genotype predicts depression in women with Alzheimer's disease: a retrospective study

OBJECTIVE

The association between the APOE epsilon4 allele and depression was investigated in a retrospective study of 323 AD patients.

METHODS

Patients were divided into demographically comparable groups based on the presence or absence of depression.

RESULTS

Results showed that the frequency of APOE epsilon4 allele was significantly higher in the depressed vs non-depressed AD patients (72% and 58%, respectively), and an interaction revealed that women possessing the APOE epsilon4 allele were almost four times more likely to be depressed than those without the epsilon4 allele.

CONCLUSION

Results are consistent with recent suggestions that the APOE epsilon4 genotype may be over-represented among depressed women with AD and highlight the need for additional research investigating the links between APOE genotype, mood, and gender.

Vascular factors and risk for neuropsychiatric symptoms in Alzheimer's disease: the Cache County Study

OBJECTIVE

To examine, in an exploratory analysis, the association between vascular conditions and the occurrence of neuropsychiatric symptoms (NPS) in a population-based sample of incident Alzheimer's disease (AD).

METHODS

The sample consisted of 254 participants, identified through two waves of assessment. NPS were assessed using the Neuropsychiatric Inventory. Prior to the onset of AD, data regarding a history of stroke, hypertension, hyperlipidemia, heart attack or coronary artery bypass graft (CABG), and diabetes were recorded. Logistic regression procedures were used to examine the relationship of each vascular condition to individual neuropsychiatric symptoms. Covariates considered were age, gender, education, APOE genotype, dementia severity, and overall health status.

RESULTS

One or more NPS were observed in 51% of participants. Depression was most common (25.8%), followed by apathy (18.6%), and irritability (17.7%). Least common were elation (0.8%), hallucinations (5.6%), and disinhibition (6.0%). Stroke prior to the onset of AD was associated with increased risk of delusions (OR = 4.76, p = 0.02), depression (OR = 3.87, p = 0.03), and apathy (OR = 4.48, p = 0.02). Hypertension was associated with increased risk of delusions (OR = 2.34, p = 0.02), anxiety (OR = 4.10, p = 0.002), and agitation/aggression (OR = 2.82, p = 0.01). No associations were observed between NPS and diabetes, hyperlipidemia, heart attack or CABG, or overall health.

CONCLUSIONS

Results suggest that a history of stroke and hypertension increase the risk of specific NPS in patients with AD. These conditions may disrupt neural circuitry in brain areas involved in NPS. Findings may provide an avenue for reduction in occurrence of NPS through the treatment or prevention of vascular risk conditions.

Pharmacogenetic basis for therapeutic optimization in Alzheimer's disease

Alzheimer's disease is a major health problem in developed countries. Approximately 10-15% of direct costs in dementia are attributed to pharmacological treatment, and only 10-20% of the patients are moderate responders to conventional antidementia drugs, with questionable cost effectiveness. The phenotypic expression of Alzheimer's disease is characterized by amyloid deposition in brain tissue and vessels (amyloid angiopathy), intracellular neurofibrillary tangle formation, synaptic and dendritic loss, and premature neuronal death. Primary pathogenic events underlying this neurodegenerative process include genetic factors involving more than 200 different genes distributed across the human genome, accompanied by progressive cerebrovascular dysfunction, and diverse environmental factors. Mutations in genes directly associated with the amyloid cascade (APP, PSEN1, PSEN2) are present in less than 5% of the Alzheimer's disease population; however, the presence of the epsilon4 allele of the apolipoprotein E gene (APOE) represents a major risk factor for more than 40% of patients with dementia. Genotype-phenotype correlation studies and functional genomics studies have revealed the association of specific mutations in primary loci and/or APOE-related polymorphic variants with the phenotypic expression of biological traits. It is estimated that genetics accounts for between 20% and 95% of the variability in drug disposition and pharmacodynamics. Recent studies indicate that the therapeutic response in Alzheimer's disease is genotype specific, depending on genes associated with Alzheimer's disease pathogenesis and/or genes responsible for drug metabolism (e.g. cytochrome P450 [CYP] genes). In monogenic studies, APOEepsilon4/epsilon4 genotype carriers are the worst responders to conventional treatments. Some cholinesterase inhibitors currently being use in the treatment of Alzheimer's disease are metabolized via CYP-related enzymes. These drugs can interact with many other drugs that are substrates, inhibitors or inducers of the CYP system, this interaction eliciting liver toxicity and other adverse drug reactions. CYP2D6 enzyme isoforms are involved in the metabolism of more than 20% of drugs used in CNS disorders. The distribution of the CYP2D6 genotypes in the European population of the Iberian peninsula differentiates four major categories of CYP2D6-related metabolizer types: (i) extensive metabolizers (EM) [51.61%]; (ii) intermediate metabolizers (IM) [32.26%]; (iii) poor metabolizers (PM) [9.03%]; and (iv) ultra-rapid metabolizers (UM) [7.10%]. PMs and UMs tend to show higher transaminase activity than EMs and IMs. EMs and IMs are the best responders, and PMs and UMs are the worst responders to pharmacologic treatments in Alzheimer's disease. At this early stage of the development of pharmacogenomic/pharmacogenetic procedures in Alzheimer's disease therapeutics, it seems very plausible that the pharmacogenetic response in Alzheimer's disease depends on the interaction of genes involved in drug metabolism and genes associated with Alzheimer's disease pathogenesis.

Pharmacogenomics and therapeutic prospects in dementia

Dementia is a major problem of health in developed countries. Alzheimer's disease (AD) is the main cause of dementia, accounting for 50-70% of the cases, followed by vascular dementia (30-40%) and mixed dementia (15-20%). Approximately 10-15% of direct costs in dementia are attributed to pharmacological treatment, and only 10-20% of the patients are moderate responders to conventional anti-dementia drugs, with questionable cost-effectiveness. Primary pathogenic events underlying the dementia process include genetic factors in which more than 200 different genes distributed across the human genome are involved, accompanied by progressive cerebrovascular dysfunction and diverse environmental factors. Mutations in genes directly associated with the amyloid cascade (APP, PS1, PS2) are only present in less than 5% of the AD population; however, the presence of the APOE-4 allele in the apolipoprotein E (APOE) gene represents a major risk factor for more than 40% of patients with dementia. Genotype-phenotype correlation studies and functional genomics studies have revealed the association of specific mutations in primary loci (APP, PS1, PS2) and/or APOE-related polymorphic variants with the phenotypic expression of biological traits. It is estimated that genetics accounts for 20-95% of variability in drug disposition and pharmacodynamics. Recent studies indicate that the therapeutic response in AD is genotype-specific depending upon genes associated with AD pathogenesis and/or genes responsible for drug metabolism (CYPs). In monogenic-related studies, APOE-4/4 carriers are the worst responders. In trigenic (APOE-PS1-PS2 clusters)-related studies the best responders are those patients carrying the 331222-, 341122-, 341222-, and 441112- genomic profiles. The worst responders in all genomic clusters are patients with the 441122+ genotype, indicating the powerful, deleterious effect of the APOE-4/4 genotype on therapeutics in networking activity with other AD-related genes. Cholinesterase inhibitors of current use in AD are metabolized via CYP-related enzymes. These drugs can interact with many other drugs which are substrates, inhibitors or inducers of the cytochrome P-450 system; this interaction elicits liver toxicity and other adverse drug reactions. CYP2D6-related enzymes are involved in the metabolism of more than 20% of CNS drugs. The distribution of the CYP2D6 genotypes differentiates four major categories of CYP2D6-related metabolyzer types: (a) Extensive Metabolizers (EM)(*1/*1, *1/*10)(51.61%); (b) Intermediate Metabolizers (IM) (*1/*3, *1/*4, *1/*5, *1/*6, *1/*7, *10/*10, *4/*10, *6/*10, *7/*10) (32.26%); (c) Poor Metabolizers (PM) (*4/*4, *5/*5) (9.03%); and (d) Ultra-rapid Metabolizers (UM) (*1xN/*1, *1xN/*4, Dupl) (7.10%). PMs and UMs tend to show higher transaminase activity than EMs and IMs. EMs and IMs are the best responders, and PMs and UMs are the worst responders to pharmacological treatments in AD. It seems very plausible that the pharmacogenetic response in AD depends upon the interaction of genes involved in drug metabolism and genes associated with AD pathogenesis. The establishment of clinical protocols for the practical application of pharmacogenetic strategies in AD will foster important advances in drug development, pharmacological optimization and cost-effectiveness of drugs, and personalized treatments in dementia.

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.

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.

Association between apolipoprotein E epsilon4 allele and apathy in probable Alzheimer's disease

OBJECTIVE

There have been inconclusive results to date on the association between the Apolipoprotein E (ApoE) genotype and neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD). We investigated whether ApoE epsilon4 allele is associated with NPS in probable AD.

METHOD

Data for 197 subjects with probable AD were analysed. The Neuropsychiatric Inventory was used to evaluate the frequency and severity of NPS. Multiple logistic regression models were used to test the association between ApoE genotype and NPS in AD.

RESULTS

The ApoE epsilon3/3 genotype was present in 52.3%, epsilon3/4 in 44.1%, and epsilon4/4 in 3.6% of patients. ApoE epsilon4 carriers showed a higher frequency of apathy than non-carriers. After multiple adjustments, the ApoE epsilon4 allele was significantly associated with apathy.

CONCLUSION

Our results suggest a relationship between the ApoE epsilon4 allele and apathy in patients with AD.

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.

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.

Review of delusions in dementia

Although delusions are common symptoms in dementia and are associated with a number of adverse outcomes, research in this area has been limited. This article attempts to summarize the existing literature on delusions in dementia with respect to known risk factors, etiology, pathogenesis, neurocognitive findings, behavioral symptoms, and treatment. This study reviews all relevant abstracts and articles pertaining to delusions and dementia. The reviewers found that the studies were limited by confusion concerning phenomenology. However, consistent findings show that delusions are associated with certain demographic variables, neuropathologic and neurocognitive findings, adverse behavioral outcomes, and limited treatment response. The authors conclude that further longitudinal studies with better clarification of terminology are required to clarify inconsistencies and shed light on future treatment options.

Strong association between Saitohin gene polymorphism and tau haplotype in the Polish population

The saitohin (STH) gene is located in intron 9 of the tau protein gene. It has been postulated that the R allele of Q7R polymorphism at the Saitohin gene is over-represented in the homozygous state in sporadic Alzheimer's disease (AD). Tau protein was implicated in AD pathophysiology and the tau gene haplotype is probably connected with sporadic late-onset Parkinson's disease (PD). We analyzed the STH polymorphism and tau gene haplotype in 100 clinically diagnosed AD cases, 100 PD cases and 100 age-matched healthy controls. We found that the R allele of the STH gene is associated with the H2 haplotype of tau in all cases. Additionally we observed no correlation between R allele frequency and AD or PD.