Jenny Bourke

Intellectual disability co-occurring with schizophrenia and other psychiatric illness: population-based study

BACKGROUND The epidemiology of intellectual disability co-occurring with schizophrenia and other psychiatric illness is poorly understood. The separation of mental health from intellectual disability services has led to a serious underestimation of the prevalence of dual diagnosis, with clinicians ill-equipped to treat affected individuals. AIMS To estimate the prevalence of dual diagnosis and describe its clinical profile. METHOD The Western Australian population-based psychiatric and intellectual disability registers were cross-linked (total n=245,749). RESULTS Overall, 31.7% of people with an intellectual disability had a psychiatric disorder; 1.8% of people with a psychiatric illness had an intellectual disability. Schizophrenia, but not bipolar disorder and unipolar depression, was greatly over-represented among individuals with a dual diagnosis: depending on birth cohort, 3.7-5.2% of those with intellectual disability had co-occurring schizophrenia. Pervasive developmental disorder was identified through the Intellectual Disability Register and is therefore limited to individuals with intellectual impairment. None the less, pervasive developmental disorder was more common among people with a dual diagnosis than among individuals with intellectual disability alone. Down syndrome was much less prevalent among individuals with a dual diagnosis despite being the most predominant cause of intellectual disability. Individuals with a dual diagnosis had higher mortality rates and were more disabled than those with psychiatric illness alone. CONCLUSIONS The facility to combine records across administrative jurisdictions has enhanced our understanding of the epidemiology of dual diagnosis, its clinical manifestations and aetiological implications. In particular, our results are suggestive of a common pathogenesis in intellectual disability co-occurring with schizophrenia.

Autism spectrum disorders in young children: effect of changes in diagnostic practices.

BACKGROUND It is unclear whether the increase in autism over the past two decades is a real increase or due to changes in diagnosis and ascertainment of autism spectrum disorders (ASDs), which include autism, Asperger syndrome and pervasive developmental disorder not otherwise specified (PDD-NOS). The aim of this study was to examine the trends in ASD over time in Western Australia (WA) and the possible effects and contribution of changes in diagnostic criteria, age at diagnosis, eligibility for service provision based on ASD diagnoses and changes in diagnostic practices. METHODS A population-based study was conducted among the cohort of children born in WA between 1983 and 1999 and diagnosed with ASD between the age of 2 and 8 years up to December 31, 2004. The trend in ASD diagnosis over the study period was assessed by investigating birth cohort and period effects, and examining whether these were modified by age of diagnosis. ASD diagnosis corresponding with changes in diagnostic criteria, funding and service provision over time were also investigated. A subgroup analysis of children aged <or=5 years was also conducted to examine trends in the incidence and age of diagnosis of ASD and intellectual disability (ID) and to investigate the role of changes in diagnostic practices. RESULTS The overall prevalence of ASD among children born between 1983 and 1999 and diagnosed by age 8 was 30 per 10,000 births with the prevalence of autism comprising 21 per 10,000 births. The prevalence of ASD increased by 11.9% per annum, from 8 cases per 10,000 births in 1983 to 46 cases per 10,000 births in 1999. The annual incidence of ASD, based on newly diagnosed ASD cases in each year from 1985 to 2002, increased over the study period. The increase in incidence of ASD appeared to coincide with changes in diagnostic criteria and availability of funding and services in WA, particularly for children aged <5 years. The age-specific rates of autism and PDD-NOS increased over time and the median age of diagnosis for autism decreased from 4 to 3 years of age throughout the 1990s. For children aged <or=5 years the incidence of ASD diagnosis increased significantly from 1992, with an average annual increase of 22%. Similar findings were found for autism. In the corresponding years the incidence of diagnosis of severe ID fell by 10% per annum and mild-moderate ID increased by 3% per annum. CONCLUSIONS The rise in incidence of all types of ASDs by year of diagnosis appears to be related to changes in diagnostic and service provision practices in WA. In children aged <or=5 years, diagnosis of severe ID decreased, but mild-moderate ID increased during the study period. A true increase in ASD cannot be ruled out.

Physical and Mental Health in Mothers of Children with Down Syndrome

OBJECTIVE To identify the relationship between characteristics of the child with Down syndrome and the health of their mother. STUDY DESIGN Families with a child/young adult with Down syndrome (<25 years) provided information related to the health of the child, functioning and behavior, and the health and well-being of the mother (n = 250). RESULTS The mean physical health score of mothers was 50.2 (SD = 9.6). Factors associated with lower mean physical health scores were as follows: child having a current heart problem (P = .036), a higher body mass index (P = .006), and higher (poorer) scores on the Developmental Behavior Checklist. Better physical health scores were seen in mothers whose children required no help/supervision in learning new skills (P = .008) and domestic tasks (P = .014). The mean mental health score of mothers was 45.2 (SD = 10.6), significantly lower than the norm of 50 (P < .0001). Associated child factors included current ear problems (P = .079), muscle/bone problems (P = .004), >4 episodes of illness in past year (P = .016), and higher scores on the DBC (P < .0001). CONCLUSIONS The most important predictors of maternal health were childrens behavioral difficulties, everyday functioning and current health status. Mothers of children with Down syndrome appear to experience poorer mental health and may require greater support and services to improve behavior management skills for their child and their own psychological well-being.

Autism and intellectual disability are differentially related to sociodemographic background at birth.

Background Research findings investigating the sociodemographics of autism spectrum disorder (ASD) have been inconsistent and rarely considered the presence of intellectual disability (ID). Methods We used population data on Western Australian singletons born from 1984 to 1999 (n = 398,353) to examine the sociodemographic characteristics of children diagnosed with ASD with or without ID, or ID without ASD compared with non-affected children. Results The profiles for the four categories examined, mild-moderate ID, severe ID, ASD without ID and ASD with ID varied considerably and we often identified a gradient effect where the risk factors for mild-moderate ID and ASD without ID were at opposite extremes while those for ASD with ID were intermediary. This was demonstrated clearly with increased odds of ASD without ID amongst older mothers aged 35 years and over (odds ratio (OR) = 1.69 [CI: 1.18, 2.43]), first born infants (OR = 2.78; [CI: 1.67, 4.54]), male infants (OR = 6.57 [CI: 4.87, 8.87]) and increasing socioeconomic advantage. In contrast, mild-moderate ID was associated with younger mothers aged less than 20 years (OR = 1.88 [CI: 1.57, 2.25]), paternal age greater than 40 years (OR = 1.59 [CI: 1.36, 1.86]), Australian-born and Aboriginal mothers (OR = 1.60 [CI: 1.41, 1.82]), increasing birth order and increasing social disadvantage (OR = 2.56 [CI: 2.27, 2.97]). Mothers of infants residing in regional or remote areas had consistently lower risk of ASD or ID and may be linked to reduced access to services or under-ascertainment rather than a protective effect of location. Conclusions The different risk profiles observed between groups may be related to aetiological differences or ascertainment factors or both. Untangling these pathways is challenging but an urgent public health priority in view of the supposed autism epidemic.

IDEA (Intellectual Disability Exploring Answers): A population-based database for intellectual disability in Western Australia

Despite the demands it places on individuals, families and the community, intellectual disability (ID) is a neglected area of public health. Accurate estimates of prevalence are sparse and range from 0.5 to 3.0%. The cause of the condition is unknown in at least 50% of cases. This paper describes the Intellectual Disability Exploring Answers (IDEA) database set up in Western Australia to provide an infrastructure for research and to facilitate the planning of service provision for people with ID. Since 1953 a database for ID has been maintained in Western Australia, a state with a population of 1.95 million in an area of 2.52 million km2. The current IDEA database aims to obtain ongoing population-based ascertainment of ID from providers of clinical and educational services, with the potential for linkage to a network of other state databases. The average prevalence of ID for children born in Western Australia over the years 1983–1996 was 15.2 per 1000 live births, with 50% ascertained only through the education system. During this time period 60% of cases were male. Of children with an ID born in Western Australia in 1980–1999 and surviving to 1 year, 30.1% had a birth defect, and the prevalence ratio of birth defects in this group compared to the population with no birth defects was 6.5 (CI 6.3–6.8).

Young adults with intellectual disability transitioning from school to post-school: A literature review framed within the ICF

Purpose: The purpose of this review was to describe literature relating to transition for young people with an intellectual disability and identify gaps within the current knowledge base. Method: A narrative literature review was undertaken. Searches of databases Medline, CINAHL, PsycINFO, ERIC, ISI Web of Science and ProQuest 500 International provided relevant research articles. The search terms used were intellectual disability, transition, employment, and ICF as well as other terms derived from the ICF. Manual searches of reference lists identified additional studies. Furthermore, government websites were searched for relevant reports and policies. Results: Transition literature was explored by ICF domains; body functions and structures, activity and participation and contextual factors. Studies were identified in some but not all areas and included literature describing self-determination and participation in leisure activities for those with mild intellectual disability. However, significant gaps were found particularly for those with severe intellectual disability. Conclusions: The ICF is a useful tool in framing a review of transition literature for young people with intellectual disability due to the complexity and multi-faceted nature of transition. The important influence of environmental factors including family systems, post-school services and access to transport were highlighted as having considerable impacts on transition outcomes. Implications for Rehabilitation The ICF is a useful tool in framing transition research to identify gaps. The current body of literature in transition from school for young adults with intellectual disabilities is too singularly focused and rarely considers those with moderate to severe intellectual disability. There has been little research on this topic in low and middle income countries. The scale of the impact of environmental factors on young people transitioning from school to post-school is currently under-represented. A holistic approach to post-school outcomes needs to be undertaken in future research.

Maternal Conditions and Perinatal Characteristics Associated with Autism Spectrum Disorder and Intellectual Disability

Background As well as being highly comorbid conditions, autism spectrum disorders (ASD) and intellectual disability (ID) share a number of clinically-relevant phenomena. This raises questions about similarities and overlap in diagnosis and aetiological pathways that may exist for both conditions. Aims To examine maternal conditions and perinatal factors for children diagnosed with an ASD, with or without ID, and children with ID of unknown cause, compared with unaffected children. Methods The study population comprised all live singleton births in Western Australia (WA) between January 1984 and December 1999 (N = 383,153). Univariate and multivariate multinomial logistic regression models were applied using a blocked modelling approach to assess the effect of maternal conditions, sociodemographic factors, labour and delivery characteristics and neonatal outcomes. Results In univariate analyses mild-moderate ID was associated with pregnancy hypertension, asthma, urinary tract infection, some types of ante-partum haemorrhage, any type of preterm birth, elective C-sections, breech presentation, poor fetal growth and need for resuscitation at birth, with all factors showing an increased risk. Severe ID was positively associated with poor fetal growth and need for resuscitation, as well as any labour or delivery complication. In the multivariate analysis no maternal conditions or perinatal factors were associated with an increased risk of ASD without ID. However, pregnancy hypertension and small head circumference were associated with a reduced risk (OR = 0.64, 95% CI: 0.43, 0.94; OR = 0.58, 95% CI: 0.34, 0.96, respectively). For ASD with ID, threatened abortion before 20 weeks gestation and poor fetal growth were associated with an increased risk. Conclusion Findings show that indicators of a poor intrauterine environment are associated with an elevated risk of ID, while for ASD, and particularly ASD without ID, the associations are much weaker. As such, these findings highlight the importance of accounting for the absence or presence of ID when examining ASD, if we are to improve our understanding of the causal pathways associated with these conditions.

A comparison of autism prevalence trends in Denmark and Western Australia

Prevalence statistics for autism spectrum disorders (ASD) vary widely across geographical boundaries. Some variation can be explained by diagnostic methods, case ascertainment and age at diagnosis. This study compared prevalence statistics for two distinct geographical regions, Denmark and Western Australia, both of which have had population-based registers and consistent classification systems operating over the past decade. Overall ASD prevalence rates were higher in Denmark (68.5 per 10,000 children) compared with Western Australia (51.0 per 10,000 children), while the diagnosis of childhood autism was more prevalent in Western Australia (39.3 per 10,000 children) compared with Denmark (21.8 per 10,000 children). These differences are probably caused by local phenomena affecting case ascertainment but influence from biological or geographical factors may exist.

Leisure participation for school-aged children with Down syndrome

Purpose. To describe leisure participation for school-aged children with Down syndrome and to investigate how factors, classified by the World Health Organisations International Classification of Functioning, Disability and Health, influence their leisure participation. Method. Families in Western Australia with a child aged 5–18 years with Down syndrome were surveyed in a population-based study (n  ==  208) in 2004. Results. One-third of parents reported that their child with Down syndrome had no friends although half reported two or more friends. Factors affecting number of friendships included the childs functional ability, behavioural issues and parents availability of time. Those children with higher functional independence scores in daily tasks were more likely to have two or more friends than those with lower functional independence scores (OR: 1.02, 95%% CI 1.01–1.04 for a single point increase in WeeFIM score). All children participated in predominantly solitary and sedentary leisure activities. Conclusions. Leisure participation was affected by complex factors both within and external to the child with Down syndrome. Further investigation of the relevance of these factors to leisure may enable more satisfying and meaningful participation in leisure for school-aged children with Down syndrome.

Variation over time in medical conditions and health service utilization of children with down syndrome

OBJECTIVES To compare the prevalence of parent reported medical conditions and rates of health service utilization in school-aged children with Down syndrome in Western Australia in 1997 and 2004. STUDY DESIGN We compared two cross-sectional surveys completed by parents of children with Down syndrome identified from population-based sources in 1997 (n = 210) and 2004 (n = 208). Surveys collected information on family demographics, medical conditions, health issues, and service utilization. The analysis described medical conditions in 2004 and compared frequencies in both years. Regression analyses compared medical conditions and health utilisation in the two cohorts. RESULTS In 2004, children with Down syndrome had greater odds of having a bowel condition (OR, 1.69; 95%, 1.16 to 2.45; P = .01), were less likely to have a current problem due to their cardiac condition (OR, 0.32; 95% CI, 0.15 to 0.68, P = .003), and demonstrated an overall reduction in episodic illnesses and infections. The use of GP services (incidence rate ratio [IRR] = 0.91; 95% CI, 0.83 to 1.00, P = .05) and combined medical specialist visits (IRR = 0.92; 95% CI, 0.84 to 1.01; P = .09) were reduced in 2004, as were overnight hospital admissions (IRR = 0.60; 95% CI, 0.37 to 0.96; P = .03) and length of stay (IRR = 0.33; 95% CI, 0.24 to 0.44; P < .001). CONCLUSIONS The health status of children with Down syndrome has varied over time with reductions in current cardiac problems, episodic illnesses, and health service use. Research is now needed to investigate the impact of these changes on the overall health and quality of life of children and families living with Down syndrome.