Andre Strydom

A genetic cause of Alzheimer disease: mechanistic insights from Down syndrome

Down syndrome, which arises in individuals carrying an extra copy of chromosome 21, is associated with a greatly increased risk of early-onset Alzheimer disease. It is thought that this risk is conferred by the presence of three copies of the gene encoding amyloid precursor protein (APP) — an Alzheimer disease risk factor — although the possession of extra copies of other chromosome 21 genes may also play a part. Further study of the mechanisms underlying the development of Alzheimer disease in people with Down syndrome could provide insights into the mechanisms that cause dementia in the general population.

Self stigma in people with intellectual disabilities and courtesy stigma in family carers: A systematic review

People with intellectual disability are one of the most stigmatised groups in society. Despite this, research in this area has been limited. This paper provides a review of studies examining self stigma in people with intellectual disability, and courtesy and affiliate stigma in family carers. An electronic search of studies published between 1990 and February 2012, using four databases and hand searching of journals was conducted. Thirty-seven papers were included in the review: 17 studies examined self stigma and 20 studies examined courtesy or affiliate stigma. The findings indicate that both individuals and family carers experience stigma and that it may have a negative impact on psychological wellbeing. Awareness of stigma in people with intellectual disability appears to be related to the extent to which individuals accept and internalise the label of intellectual disability. Most of the studies were qualitative studies or small descriptive studies. There is a lack of large prevalence studies and longitudinal studies examining the impact of stigma, in both individuals with intellectual disability and their carers.

Mental illness, challenging behaviour, and psychotropic drug prescribing in people with intellectual disability: UK population based cohort study.

Objectives To describe the incidence of recorded mental illness and challenging behaviour in people with intellectual disability in UK primary care and to explore the prescription of psychotropic drugs in this group. Design Cohort study. Setting 571 general practices contributing data to The Health Improvement Network clinical database. Participants 33 016 adults (58% male) with intellectual disability who contributed 211 793 person years’ data. Main outcome measures Existing and new records of mental illness, challenging behaviour, and psychotropic drug prescription. Results 21% (7065) of the cohort had a record of mental illness at study entry, 25% (8300) had a record of challenging behaviour, and 49% (16 242) had a record of prescription of psychotropic drugs. During follow-up, the rate of new cases of mental illness in people without a history at cohort entry was 262 (95% confidence interval 254 to 271) per 10 000 person years and the rate of challenging behaviour was 239 (231 to 247) per 10 000 person years. The rate of new psychotropic drug prescription in those without a previous history of psychotropic drug treatment was 518 (503 to 533) per 10 000 person years. Rates of new recording of severe mental illness declined by 5% (95% confidence interval 3% to 7%) per year (P<0.001), and new prescriptions of antipsychotics declined by 4% (3% to 5%) per year P<0.001) between 1999 and 2013. New prescriptions of mood stabilisers also decreased significantly. The rate of new antipsychotic prescribing was significantly higher in people with challenging behaviour (incidence rate ratio 2.08, 95% confidence interval 1.90 to 2.27; P<0.001), autism (1.79, 1.56 to 2.04; P<0.001), and dementia (1.42, 1.12 to 1.81; P<0.003) and in those of older age, after control for other sociodemographic factors and comorbidity. Conclusions The proportion of people with intellectual disability who have been treated with psychotropic drugs far exceeds the proportion with recorded mental illness. Antipsychotics are often prescribed to people without recorded severe mental illness but who have a record of challenging behaviour. The findings suggest that changes are needed in the prescribing of psychotropics for people with intellectual disability. More evidence is needed of the efficacy and safety of psychotropic drugs in this group, particularly when they are used for challenging behaviour.

The relationship of dementia prevalence in older adults with intellectual disability (ID) to age and severity of ID.

BACKGROUND Previous research has shown that adults with intellectual disability (ID) may be more at risk of developing dementia in old age than expected. However, the effect of age and ID severity on dementia prevalence rates has never been reported. We investigated the predictions that older adults with ID should have high prevalence rates of dementia that differ between ID severity groups and that the age-associated risk should be shifted to a younger age relative to the general population. METHOD A two-staged epidemiological survey of 281 adults with ID without Down syndrome (DS) aged 60 years; participants who screened positive with a memory task, informant-reported change in function or with the Dementia Questionnaire for Persons with Mental Retardation (DMR) underwent a detailed assessment. Diagnoses were made by psychiatrists according to international criteria. Prevalence rates were compared with UK prevalence and European consensus rates using standardized morbidity ratios (SMRs). RESULTS Dementia was more common in this population (prevalence of 18.3%, SMR 2.77 in those aged 65 years). Prevalence rates did not differ between mild, moderate and severe ID groups. Age was a strong risk factor and was not influenced by sex or ID severity. As predicted, SMRs were higher for younger age groups compared to older age groups, indicating a relative shift in age-associated risk. CONCLUSIONS Criteria-defined dementia is 2-3 times more common in the ID population, with a shift in risk to younger age groups compared to the general population.

Discrimination and Other Barriers to Accessing Health Care: Perspectives of Patients with Mild and Moderate Intellectual Disability and Their Carers

Background People with intellectual disability have a higher prevalence of physical health problems but often experience disparities in accessing health care. In England, a number of legislative changes, policies and recommendations have been introduced to improve health care access for this population. The aim of this qualitative study was to examine the extent to which patients with intellectual disability and their carers experience discrimination or other barriers in accessing health services, and whether health care experiences have improved over the last decade years. Method and Main Findings Twenty nine participants (14 patient and carer dyads, and one carer) took part in semi-structured interviews. The interviews were audio-taped and transcribed and analysed using thematic analysis. Eight themes were identified. Half the participants thought that the patient had been treated unfairly or had been discriminated against by health services. There were accounts of negative staff attitudes and behaviour, and failure of services to make reasonable adjustments. Other barriers included problems with communication, and accessing services because of lack of knowledge of local services and service eligibility issues; lack of support and involvement of carers; and language problems in participants from minority ethnic groups. Most participants were able to report at least one example of good practice in health care provision. Suggestions for improving services are presented. Conclusion Despite some improvements to services as a result of health policies and recommendations, more progress is required to ensure that health services make reasonable adjustments to reduce both direct and indirect discrimination of people with intellectual disability.

Incidence of dementia in older adults with intellectual disabilities

Dementia may be more common in older adults with intellectual disability (ID) than in the general population. The increased risk for Alzheimers disease in people with Down syndrome (DS) is well established, but much less is known about dementia in adults with ID who do not have DS. We estimated incidence rates from a longitudinal study of dementia in older adults with ID without DS and compared them to general population rates. 222 participants with ID without DS aged 60 years and older were followed up an average of 2.9 years later to identify those who had declined in functional or cognitive abilities. Those who screened positive had a comprehensive assessment for dementia, diagnosed using ICD 10 and DSM IV criteria. 134 participants who did not have dementia at initial assessment were alive and interviewed at follow up; 21 (15.7%) were diagnosed with dementia. Overall incidence rate for those aged ≥ 60 was 54.6/1000 person years (95% CI 34.1-82.3). The highest incidence rate (97.8/1000 person years) was in the age group 70-74. Standardised incidence ratio for those aged ≥ 65 was 4.98 (95% CI 1.62-11.67). Incidence of dementia in older people with intellectual disabilities are up to five times higher than older adults in the general population. Screening may be useful in this population given the high incident rates, particularly as more effective treatments become available. Studies to explore the underlying aetiological factors for dementia associated with intellectual disability could help to identify novel protective and risk factors.

Diagnostic instruments for dementia in older people with intellectual disability in clinical practice.

There is a need for simple and reliable screening instruments for dementia in the intellectual disability (ID) population that can also be used to follow their progress, particularly if they are being treated with anti-dementia drugs. Commonly used tests for the general population such as the Mini Mental State Examination (MMSE) are not appropriate for many people with ID. This paper is a literature review of alternative instruments that have been used in research or recommended by experts since 1991 and have the potential to be used as screening instruments. Two types of tests have been identified: those administered to informants, and those that rely on direct assessment of the individual. The most promising informant rated screening tool in most adults with ID including Down syndrome (DS) diagnosis is the Dementia Questionnaire for Persons with Mental Retardation (DMR). However, sensitivity in single assessments is variable and cut-off scores need further optimisation. In those with DS, the Dementia Scale for Down Syndrome (DSDS) has good specificity but mediocre sensitivity. The Test for Severe Impairment and Severe Impairment Battery are two direct assessment tools that show promise as screening instruments, but need further evaluation.

Service use and cost of mental disorder in older adults with intellectual disability

BACKGROUND The cost of caring for people with intellectual disability currently makes up a large proportion of healthcare spending in western Europe, and may rise in line with the increasing numbers of people with intellectual disability now living to old age. AIMS To report service use and costs of older people with intellectual disability and explore the influence of sociodemographic and illness-related determinants. METHOD We collected data on receipt and costs of accommodation, health and personal care, physical as well as mental illness, dementia, sensory impairment and disability in a representative sample of adults with intellectual disability aged 60 years and older (n = 212). RESULTS The average weekly cost in GBP per older person was 790 pounds (41,080 pounds per year). Accommodation accounted for 74%. Overall costs were highest for those living in congregate settings. Gender, intellectual disability severity, hearing impairment, physical disorder and mental illness had significant independent relationships with costs. Mental illness was associated with an additional weekly cost of 202 pounds. CONCLUSIONS Older adults with intellectual disability comprise about 0.15-0.25% of the population of England but consume up to 5% of the total personal care budget. Interventions that meet needs and might prove to be cost-effective should be sought.

Oxidative stress and cognitive ability in adults with Down syndrome

AIMS We aimed to study the hypothesis that high levels of superoxide dismutase (SOD1), previously reported in Down syndrome, would be associated with poorer ability on cognitive tests. Compensatory rises in the activity of glutathione peroxidase (GPx) was expected to be associated with better ability, so that a high ratio between SOD1 and GPx was hypothesised to be the best predictor of poorer cognitive performance. METHODS 32 adults with Down syndrome between the ages of 18 and 45 years donated blood samples for SOD1 and GPx assays and urine for Isoprostane 8,12-iso-iPF(2alpha)-VI assay, a specific biomarker of lipid peroxidation in vivo. Informants rated functional ability and memory function for all participants, and those adults with DS that was able to, also completed psychometric assessments of language ability and memory. RESULTS Neither SOD1 nor GPx were related to the elevated markers of lipid peroxidation previously described in living adults with DS, and our hypothesis that an increased SOD1/GPx ratio would be correlated with worse performance on cognitive or functional measures was not supported. Contrary to our hypothesis, we found that low SOD1/GPx ratios were associated with worse memory ability, which remained after controlling for confounders such as sex, age or nutritional supplements. CONCLUSIONS The anti-oxidant system in DS is implicated in the cognitive phenotype associated with the chromosomal disorder, but the variations in the phenotype could result from several possible gene or gene product interactions. Much further research is required before it will be possible to counteract the oxidative stress associated with DS.

Psychiatric morbidity in prisoners with intellectual disabilities: analysis of prison survey data for England and Wales

A substantial number of prisoners have intellectual disabilities. We analysed data on a sample drawn from all prisons in England and Wales. Intellectual disability was defined as Quick Test scores equivalent to an IQ of ≤65. We found a significantly higher prevalence of probable psychosis, attempted suicide and cannabis use in prisoners with intellectual disabilities. Presence of intellectual disability was twice as likely to be associated with probable psychosis but the relationship was fully mediated by self-rated health status. It is important to identify this group as early as possible in order to provide timely interventions to cope in adverse environments and manage substance misuse.