The 5-HTTPR polymorphism confers liability to a combined phenotype of psychotic and aggressive behavior in Alzheimer disease

Neuropsychiatric symptoms in dementia: importance and treatment considerations

Neuropsychiatric symptoms are frequent in people with dementia, result in distress for the people experiencing them and their caregivers, and are a common precipitant of institutional care. The safe and effective treatment of these symptoms is a key clinical priority, but is a long way from being achieved. Psychological interventions are recommended as the first line treatment strategy in most good practice guidelines, and there is emerging evidence of efficacy for agitation and depression. Neuroleptics remain the mainstay of pharmacological treatment, although meta-analyses indicate that they are mainly of benefit for the short-term (up to 12 weeks) treatment of aggression in people with Alzheimer's disease, and there have been increasing concerns about serious adverse effects including mortality. The evidence is limited for other pharmacological approaches for the treatment of agitation, and psychosis in people with Alzheimer's disease is limited, but post-hoc analyses do indicate that memantine may be a promising therapy and aromatherapy may be a useful alternative. Autopsy studies indicate that the adrenergic system may be an important therapeutic target. Clinical experience suggests that antidepressants are effective in people with severe depression in the context of dementia, but the evidence base regarding the broader value of antidepressants is far from clear. There are very few trials specifically focusing upon the treatment of neuropsychiatric symptoms in common non-Alzheimer dementias, which is a major limitation and urgently needs to be addressed to provide an evidence base to enable the safe and effective treatment of these individuals.

Aggression in individuals newly diagnosed with dementia

Aggression is often associated with dementia. In this study, aggression in veterans newly diagnosed with dementia was examined and characterized. Participants were >or=60 years diagnosed with dementia at the Michael E. DeBakey Veterans Affairs Medical Center in Houston, Texas, from 2001 to 2004. Aggression was defined as a positive caregiver response to 1 or more of 3 probes from the Ryden Aggression Scale, administered during a telephone screen. Of 1276 contacts, 385 (30%) were eligible and agreed to participate; at initial screening, 75 (19.5%) were aggressive (23 [31%] verbally, 9 [12%] physically, 24 [32%] verbally and physically, and 19 [25%] with unspecified aggression). The surprisingly high prevalence of aggression in individuals newly diagnosed with dementia suggests the potential usefulness of early screening for aggression in this population.

Antipsychotics for the treatment of behavioral and psychological symptoms of dementia (BPSD)

Behavioral and psychological symptoms of dementia (BPSD), i.e. verbal and physical aggression, agitation, psychotic symptoms (hallucinations and delusions), sleep disturbances, oppositional behavior, and wandering, are a common and potentially severe problem complicating dementia. Their prevalence is very high and it is estimated that up to 90% of patients with Alzheimer's disease (AD) may present at least one BPSD. Beside the obvious impact on the quality of life of people with dementia, BPSD are responsible for increased risk of patient institutionalization and increased costs. Furthermore, they are associated with caregivers' stress and depression. Drugs used include antipsychotics, antidepressants, anticonvulsivants, anxiolytics, cholinesterase inhibitors and N-methyl-D-aspartate receptor modulators. Among these, the most commonly used are anti-psychotics. These drugs have been used for many decades, but in the last years new compounds have been marketed with the promise of comparable efficacy but less frequent adverse effects (especially extra-pyramidal side effects). Their safety, however, has been challenged by data showing a potential increase in adverse cerebrovascular side effects and mortality. This review will summarize the pathophysiology and neuropharmacology of BPSD, it will describe the characteristics of the anti-psychotics most commonly used focusing on their efficacy and safety in BPSD.

A double-blind comparison of citalopram and risperidone for the treatment of behavioral and psychotic symptoms associated with dementia

OBJECTIVE

To compare citalopram and risperidone for the treatment of psychotic symptoms and agitation associated with dementia, with a priori hypotheses that risperidone would be more efficacious for psychosis and citalopram for agitation.

METHODS

A 12-week randomized, controlled trial in nondepressed patients with dementia hospitalized because of behavioral symptoms (N = 103) was conducted at the University of Pittsburgh Medical Center. Participants were consecutively recruited on an inpatient unit if they had at least one moderate to severe target symptom (aggression, agitation, hostility, suspiciousness, hallucinations, or delusions). Once they improved sufficiently, they were discharged to nursing homes, personal care homes, or residential homes for continued treatment. Planned pre-post and mixed model analyses of the main outcome measures of Neurobehavioral Rating Scale and Side Effect Rating Scale at baseline and at weekly/biweekly intervals were conducted.

RESULTS

Completion rates did not differ for citalopram and risperidone (overall completion rate: 44%). Agitation symptoms (aggression, agitation, or hostility) and psychotic symptoms (suspiciousness, hallucinations, or delusions) decreased in both treatment groups but the improvement did not differ significantly between the two groups. There was a significant increase in side effect burden with risperidone but not with citalopram such that the two groups differed significantly.

CONCLUSION

No statistical difference was found in the efficacy of citalopram and risperidone for the treatment of either agitation or psychotic symptoms in patients with dementia. These findings need to be replicated before citalopram or other serotonergic antidepressants can be recommended as alternatives to antipsychotics for the treatment of agitation or psychotic symptoms associated with dementia.

Role of serotonin transporter polymorphisms in the behavioural and psychological symptoms in probable Alzheimer disease patients

BACKGROUND/AIMS

Alzheimer disease (AD) patients commonly suffer from behavioural and psychological symptoms of dementia (BPSD). A genetic component to BPSD development in AD has been demonstrated. This is an investigation of whether the linked polymorphic region and variable number tandem repeat variants of the serotonin transporter (SERT) are associated with BPSD.

METHODS

The longitudinal measures of BPSD of our large cohort of 367 AD patients were assessed by the Neuropsychiatric Inventory. Measures with good evidence of serotonergic involvement (delusions, hallucinations, depression, anxiety, agitation/aggression and irritability) were related to genotype and allele frequencies of the linked polymorphic region and variable number tandem repeat variants.

RESULTS

Analysis revealed significant relationships between the linked polymorphic region variant long allele with irritability and the variable number tandem repeat 10-repeat allele with psychosis, but no associations were found with depression, anxiety or agitation/aggression.

CONCLUSION

Our data and review of previous studies suggest SERT could play a minor role in development of psychosis and aggressive/irritable tendencies; however, further investigations are required in large, well-characterized cohorts.

Brief report: aggression and stereotypic behavior in males with fragile X syndrome--moderating secondary genes in a "single gene" disorder

Although fragile X syndrome (FXS) is a single gene disorder with a well-described phenotype, it is not known why some individuals develop more significant maladaptive behaviors such as aggression or autistic symptoms. Here, we studied two candidate genes known to affect mood and aggression, the serotonin transporter (5-HTTLPR) and monoamine oxidase A (MAOA-VNTR) polymorphisms, in 50 males with FXS ages 8-24 years. Mothers and fathers of participants reported the frequency and severity of aggressive/destructive, self-injurious, and stereotypic behaviors. Polymorphism genotypes were unrelated to age and IQ. Results showed a significant effect of 5-HTTLPR genotype on aggressive/destructive and stereotypic behavior; males with FXS who were homozygous for the high-transcribing long (L/L) genotype had the most aggressive and destructive behavior, and individuals homozygous for the short (S/S) genotype had the least aggression. Those with the L/L genotype also had the highest levels of stereotypic behavior. There was no effect of MAOA-VNTR on behavior; however those with the high-activity, 4-repeat genotype were more likely to be taking SSRI or SNRI medication. This preliminary study prompts consideration of secondary genes that may modify behavioral phenotype expression in neurodevelopmental disorders, even those with a single gene etiology such as FXS.

Analysis of the 5HT-2A T102C receptor polymorphism and psychotic symptoms in Alzheimer's disease

Although the aetiology of psychotic symptoms in Alzheimer's disease (AD) is multi-factorial, alterations in serotonergic neurotransmission are often implicated. Polymorphisms of the serotonin receptor 5HT-2A are associated with hallucinatory symptoms and delusions in demented and non-demented cohorts. This study examined the role of the 5HT-2A T102C polymorphism in influencing psychotic symptoms in a large Northern Ireland AD population (n = 406, mean MMSE 13/30). Forty-eight percent of patients experienced delusional symptoms and 28% experienced hallucinations during the course of their dementia. No significant association was found either in frequency of genotype or allelic variation for either set of symptoms. Furthermore, the mean delusional and hallucinatory severity scores did not differ significantly among the three genotype groups. The lack of influence of the T102C polymorphism of the 5HT-2A receptor on the emergence of psychotic symptoms in AD contrasts with previous reports in other cohorts involving smaller numbers of subjects.

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.

Neuroleptic drugs in dementia: benefits and harm

Neuroleptic (antipsychotic) drugs are often used to treat psychiatric symptoms frequently seen in dementia, but their use is controversial. We present a new meta-analysis to assess the efficacy of these drugs for the treatment of psychiatric symptoms in Alzheimer's disease, and discuss the more limited evidence for their potential benefits in other dementias. We recommend that these treatments be limited to the short-term treatment of psychiatric symptoms associated with serious distress or risk.

Prediction of psychosis onset in Alzheimer disease: The role of cognitive impairment, depressive symptoms, and further evidence for psychosis subtypes

BACKGROUND

Psychotic symptoms in Alzheimer disease (AD+P) identify a heritable phenotype associated with more rapid cognitive decline. The authors have proposed that AD+P is itself a composite of a misidentification and a paranoid subtype with increased cognitive impairment restricted to the misidentification type. Most prior studies of the clinical correlates of AD+P have been limited, however, by the inclusion of prevalent cases.

METHODS

Subjects with possible or probable AD or mild cognitive impairment (MCI) without psychosis at study entry were assessed at the time of initial presentation and then annually. Psychotic symptoms were assessed using the CERAD Behavioral Rating Scale. Survival analyses used Cox proportional hazard models with time-dependent covariates to examine the predictors of psychosis onset.

RESULTS

A total of 288 subjects completed at least one follow-up examination. Mean duration of follow-up was 22.1 months. The incidence of psychosis was 0.19 per person-year. Cognitive impairment was associated with onset of psychosis, largely as a result of its association with onset of the misidentification, but not the paranoid, subtype. Including psychotropic medication use in the model revealed an association of antidepressant use with the onset of psychosis. This latter association appeared to arise from an underlying association between depression and the risk of psychosis onset rather than from antidepressant treatment.

CONCLUSION

These findings are consistent with the hypothesis that the misidentification and the paranoid subtypes each define a more biologically homogeneous group than AD+P as a whole. Further exploration of the relationship between depressive symptoms and psychosis in patients with AD is warranted.

Treatments for behavioural disorders in neurodegenerative diseases: drug development strategies

Neuropsychiatric symptoms and behavioural alterations are common in neurodegenerative diseases, and effective treatment of these changes represents an important unmet public health need. Imaging, neuropathological, neurotransmitter and molecular genetic studies increasingly identify specific mechanisms that mediate behavioural changes in neurodegenerative disorders and provide a platform for seeking effective therapeutic interventions. Measuring behavioural outcomes in clinical trials of antidementia agents represents an important means of evaluating treatment effectiveness, and clinical trial methodologies and behavioural instrumentation are evolving to facilitate drug development in this important therapeutic target area.

Association study of polymorphisms in LRP1, tau and 5-HTT genes and Alzheimer’s disease in a sample of Colombian patients

Analysis of genetic susceptibility factors for Alzheimer's disease (AD) in populations with different genetic and environmental background may be useful to understand AD etiology. There are few genetic association studies of AD in Latin America. In the present work, we analyzed polymorphisms in 3 candidate genes; the LDL receptor related protein-1, the microtubule-associated protein Tau and the serotonin transporter genes in a sample of 106 Colombian AD patients and 97 control subjects. We did not find a significant allelic or genotypic association with any of the three polymorphisms analyzed using different statistical analysis, including a neural network model or different sample stratifications. To date, APOE polymorphisms are the only genetic risk factors identified for AD in the Colombian population. It may be factible that future combination of high-throughput genotyping platforms and multivariate analysis models may lead to the identification of other genetic susceptibility factors for AD in the Colombian population.

Catechol-O-methyltransferase haplotypes are associated with psychosis in Alzheimer disease

Psychotic symptoms in subjects with Alzheimer disease (AD with psychosis, AD+P) define a phenotype characterized by greater cognitive burden than in AD without psychosis. We have proposed that genes of small effect may contribute to the risk for expression of psychosis in multiple disorders, including AD. Recently, sex-differential association of a three-locus haplotype, including a G-->A transition at codon 108/158 of catechol-O-methyltransferase (COMT) resulting in a Val-->Met substitution, has been reported to confer an increased risk for schizophrenia. The main objective of the study was to determine if COMT genetic variation is associated with risk of psychosis in AD, and included a case-control study of 373 individuals diagnosed with AD with, or without, psychosis. All subjects were characterized for alleles at the three loci associated with schizophrenia, RS737865, COMT G-->A 108/158 (RS4680), and RS165599, and for a C/T transition adjacent to an estrogen response element (ERE6) in the COMT P2 promoter region. Both single locus and haplotype tests of association were conducted. Logit models were used to examine independent and interacting effects of alleles at the associated loci. All analyses were stratified by sex. In female subjects, RS4680 demonstrated a modest association with AD+P; RS737865 demonstrated a trend towards an association. There was a highly significant association of AD+P with the four-locus haplotype, which resulted from additive effects of alleles at RS4680 and ERE6 (or RS737865, as this locus was in almost absolute linkage disequilibrium (LD) with ERE6). In male subjects, no single locus test was significant, but there remained a strong association between AD+P and the four-locus haplotype. This association appeared to result from interaction of the ERE6/RS737865, RS4680, and RS165599 loci. Genetic variation in COMT is associated with AD+P, and thus appears to contribute to psychosis risk across disorders. Sex-differential associations of COMT with psychosis may result from variation at, or in LD with, ERE6. Examination of variation at ERE6 in subjects with schizophrenia, and further examination of the independent and additive effects of variations in COMT on gene expression, is warranted.

Genetic correlates of behavioral endophenotypes in Alzheimer disease: role of COMT, 5-HTTLPR and APOE polymorphisms

Several studies have been conducted to understand the genetic correlates of Alzheimer disease (AD)-related behavioral and psychological symptoms in dementia (BPSD). However, given that BPSD rarely occur in isolation, it has been suggested that targeting BPSD individually is too narrow of an approach if one wants to accurately define all the associated risk factors. To date, we know of no work on genetic polymorphisms related to behavioral endophenotypes in AD. The present study sought to evaluate the relationship between such behavioral endophenotypes in AD and genetic variations in dopamine- or serotonin-related genes, such as catechol-O-methyltransferase (COMT) or 5-HTT gene-linked promoter region (5-HTTLPR), and apolipoprotein E (APOE). Among 232 AD patients who underwent clinical and neuropsychological examination, a behavioral and psychiatric evaluation, and genotyping at COMT, 5-HTTPLR, and APOE; 66.4% showed more than one behavioral symptom. By Principal Component Analysis of Neuropsychiatric Inventory (NPI) symptoms four endophenotypes were identified, these were termed "psychosis", "moods", "apathy", and "frontal". Modeling NPI symptom-endophenotype-genotype relationships, and taking into account possible confounds (i.e. demographic characteristics, comorbidities, concomitant pharmacological treatments, and disease severity) by latent variable models, COMT and 5-HTTLPR genetic variations correlated with "frontal" and "psychosis" endophenotypes. APOE genotype did not correlate with any endophenotype. These findings suggest that the possibility of identifying distinct phenotypes on a genetic basis among AD patients exists, and suggest that clustering of BPSD into endophenotypes might provide a new strategy for guiding future research on this issue.

Evaluating associations between 5-HTTLPR polymorphism and Alzheimer's disease for Korean patients

There has been growing evidence that the serotonin (5-HT) system is important in the regulation of memory and thus might be associated with Alzheimer's disease (AD), while research results on this issue have been inconsistent. The 5-HT system has also been suggested to be responsible for a significant portion of the behavioural aspects of AD. This study aimed to investigate the associations of the 5-HT transporter gene linked polymorphic region (5-HTTLPR) polymorphism with AD and delusional/aggressive symptoms of AD in Korean samples of 65 patients and 43 controls. The 5-HTTLPR polymorphism was neither associated with AD nor with delusional/aggressive symptoms of AD. It was suggested that phenotypic expression of the 5-HTTLPR polymorphism might be varied according to ethnic differences.

Effects of serotonin transporter promoter polymorphisms on serotonin function

The serotonin transporter promoter polymorphism (5-HTTLPR) has been associated with vulnerability to stress-induced depressive symptoms and with the speed and rate of response to antidepressant treatment. The goal of the present study was to evaluate the association between the 5-HTTLPR and the functional response of the serotonin system as measured by the neuroendocrine and cerebral metabolic response to intravenous administration of the selective serotonin reuptake inhibitor citalopram in normal control subjects. Genotyping was performed for 5-HTTLPR insertion/deletion polymorphism long (l) and short (s) variant alleles. The ll genotype was compared with the combined sl+ss and with the ss genotype alone. Citalopram plasma concentrations did not differ significantly between groups. The s allele was associated with a less of an increase in prolactin and cortisol than the ll genotype. The s allele was associated with greater decreases in left frontal, precentral and middle temporal gyri compared to the ll genotype. The ll genotype was associated with greater decreases in right frontal, insula and superior temporal gyrus compared to the ss genotype. These findings suggest that 5-HTTLPR is associated with an altered functional response of the serotonin system, which may represent a neurobiologic substrate for the differential response to antidepressant treatment in late life and the emergence of neuropsychiatric symptoms in neurodegenerative disorders.

Association of aggressive behavior in Korean male schizophrenic patients with polymorphisms in the serotonin transporter promoter and catecholamine-O-methyltransferase genes

The incidence of aggressive behavior in patients with schizophrenia is higher than in the general population. Among particular gene polymorphisms posited to be involved in psychiatric disorders, the catecholamine-O-methyltransferase (COMT) and serotonin transporter (5-HTTPR) genes have been the focus of recent research on aggression. In this study, we hypothesized that both the COMT and the 5-HTTPR genotypes may be dependent on and related to aggression in Korean patients with schizophrenia. The subjects were 168 unrelated male schizophrenic patients diagnosed according to DSM-IV. Among two psychiatric hospital staff and medical university students, 158 unrelated male subjects with no lifetime history of psychiatric disorders were recruited to establish the COMT and 5-HTTPR genotype distribution in the general population. All episodes of aggression from the last discharge to readmission were rated. The Total Overt Aggression Scale (OAS) score (sum of the scores of all episodes of aggression), highest OAS score (highest individual episode score, 0-16), OAS category, and OAS category score (mean score within each category) were recorded. There were statistically significant effects of COMT genotype on the mean OAS 4 (physical aggression against other people) score and the highest OAS score. The most predictive was the OAS 4 score. There was a statistically significant effect of 5-HTTPR genotype on mean total score. Thus, the COMT gene is associated with the severity of aggression and with physical aggression against other people, whereas the 5-HTTPR gene is associated with the summary score of all episodes of aggression.

Allelic variation at the A218C tryptophan hydroxylase polymorphism influences agitation and aggression in Alzheimer's disease

The behavioural and psychological symptoms of dementia are common, distressing to carers, and directly linked to the requirement for institutional care. Symptoms of aggression and agitation are particularly difficult for carers to tolerate. The origin of these features is unclear although genetic and environmental modification of pre-frontal serotonergic circuitry which regulates the control of negative emotions is proposed. Following the suggestion that the A218C intronic polymorphism of the tryptophan hydroxylase gene influences aggression and anger in non-demented individuals, we tested the influence of A218C on symptoms of agitation/aggression in 396 Alzheimer's disease patients using the Neuropsychiatric Inventory. Overall, 50% of participants experienced agitation/aggression in the month prior to interview. It was observed that male patients with a history of agitation/aggression were more likely to possess C-containing genotypes (P = 0.044, OR = 1.65, CI = 0.98-2.76). We conclude that aggression in male subjects with Alzheimer's disease may be genetically linked to polymorphic variation at the tryptophan hydroxylase gene.

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.