Behaviour phenotype for Down's syndrome

Developmental Functioning of Toddlers At-Risk for Autism With and Without Down Syndrome

PURPOSE

Due to the difficulties in differentiating between impairments associated with intellectual disability and ASD symptomology, DS often leads to delayed or misdiagnoses of ASD.

METHOD

An ANOVA was run to investigate the effects of ASD risk and DS on overall developmental functioning across three groups: ASD+, DS-, and DS+ (n = 138). A MANOVA was run to investigate the differences of group on five developmental subdomains.

RESULTS

The results revealed significant group differences in the overall developmental functioning and each developmental subdomain. Children in the DS+ group demonstrated significantly lower overall developmental functioning, as well as lower adaptive, cognitive, motor, and communication skills compared to their peers; however, children in the DS- group demonstrated significantly better social skills compared to their peers in the ASD+ group.

DISCUSSION

These findings support the need for early screening and identification of ASD among those with DS.

The sociability spectrum: evidence from reciprocal genetic copy number variations

Sociability entails some of the most complex behaviors processed by the central nervous system. It includes the detection, integration, and interpretation of social cues and elaboration of context-specific responses that are quintessentially species-specific. There is an ever-growing accumulation of molecular associations to autism spectrum disorders (ASD), from causative genes to endophenotypes across multiple functional layers; these however, have rarely been put in context with the opposite manifestation featured in hypersociability syndromes. Genetic copy number variations (CNVs) allow to investigate the relationships between gene dosage and its corresponding phenotypes. In particular, CNVs of the 7q11.23 locus, which manifest diametrically opposite social behaviors, offer a privileged window to look into the molecular substrates underlying the developmental trajectories of the social brain. As by definition sociability is studied in humans postnatally, the developmental fluctuations causing social impairments have thus far remained a black box. Here, we review key evidence of molecular players involved at both ends of the sociability spectrum, focusing on genetic and functional associations of neuroendocrine regulators and synaptic transmission pathways. We then proceed to propose the existence of a molecular axis centered around the paradigmatic dosage imbalances at the 7q11.23 locus, regulating networks responsible for the development of social behavior in humans and highlight the key role that neurodevelopmental models from reprogrammed pluripotent cells will play for its understanding.

Down syndrome

Down syndrome (DS; Trisomy 21) is the most common chromosomal disorder in humans. It has numerous associated neurologic phenotypes including intellectual disability, sleep apnea, seizures, behavioral problems, and dementia. With improved access to medical care, people with DS are living longer than ever before. As more individuals with DS reach old age, the necessity for further life span research is essential and cannot be overstated. There is currently a scarcity of information on common medical conditions encountered as individuals with DS progress into adulthood and old age. Conflicting information and uncertainty about the relative risk of dementia for adults with DS is a source of distress for the DS community that creates a major obstacle to proper evaluation and treatment. In this chapter, we discuss the salient neurologic phenotypes of DS, including Alzheimer's disease (AD), and current understanding of their biologic bases and management.

Brief Report: Contrasting Profiles of Everyday Executive Functioning in Smith-Magenis Syndrome and Down Syndrome

Everyday executive function (EF) was examined in Smith-Magenis syndrome (SMS), associated with high risk of behaviour disorder, and Down syndrome (DS), associated with relatively low risk of behaviour disorder. Caregivers of 13 children with SMS and 17 with DS rated everyday EF using the Behavioral Rating Inventory of Executive Functioning-Preschool. Greater everyday EF deficits relative to adaptive ability were evident in SMS than in DS. The SMS profile of everyday EF abilities was relatively uniform; in DS emotional control strengths and working memory weaknesses were evident. Findings implicate broad everyday EF difficulties in SMS compared to DS, corresponding with increased rates of behaviour disorder in SMS. Findings further suggest that everyday EF profiles may, in part, be syndrome related.

Relationship between Psychological Capital and Psychological Well-Being of Direct Support Staff of Specialist Autism Services. The Mediator Role of Burnout

This study investigates the specific role of burnout as a mediator in the relationship between psychological capital and psychological well-being (PWB) in direct support staff of specialist autism services. A time lagged design with three data-collection points was conducted to survey 56 professionals (direct support staff) who work at a Spanish center specialized in autism. Participants completed measures of psychological capital, burnout and PWB. The hypothesized model was tested using structural equation modeling. Our findings show that psychological capital has a significant main effect on PWB. The results also show that psychological capital in the work environment should result in lower burnout which in turn, should lead to higher degrees of PWB in the direct support staff of autism services. Our results support that psychological capital is a key variable in the working life of the direct support staff of autism services. The findings suggest the need of implementing programmes which strengthen each individual's psychological capital in order to prevent burnout and achieve a greater PWB.

Psychometric characteristics of the adult scale of hostility and aggression: reactive/proactive (A-SHARP) and relation to psychiatric features of adults with developmental disabilities

Recently, we described the development of the Adult Scale of Hostility and Aggression: Reactive/Proactive (A-SHARP) (Matlock & Aman, 2011). The A-SHARP was derived by factor analysis of ratings of 512 adults with intellectual and developmental disabilities (IDD), and its resulting five subscales were designated as (1) Verbal Aggression, (2) Physical Aggression, (3) Hostile Affect, (4) Covert Aggression, and (5) Bullying. The items on each subscale are rated first for severity (the Problem scale) and second for "origin" (i.e., to reflect extent to which behaviors are planned or reactive; "Provocation scale"). This study evaluated psychometric characteristics of the A-SHARP in the developmental sample of 512 adults. Mean item-whole subscale correlations ranged from .67 (Physical Aggression) to .78 (Verbal Aggression) on the Problem scale. Interrater reliability (n=39) ranged from .59 to .78 on the Problem subscales and from .54 to .78 on the Provocation subscales. For the entire sample, the correspondence between the Problem and Provocation subscales was low (-0.04 to 0.28), indicating independence between the scales. The A-SHARP Physical subscale was strongly correlated with Behavior Problems Inventory (BPI) Aggression frequency ratings (n=512, r=0.79), and strongly with BPI severity ratings (r=.86). We examined congruent validity between A-SHARP subscale scores on the one hand and four DSM-IV categories and Down syndrome on the other. A number of significant associations were observed between the A-SHARP subscales and diagnostic group, supporting the A-SHARP's congruent validity. Likewise, we examined the correspondence between use of psychoactive medicines and A-SHARP scores and found a number of associations between medication use and higher subscale scores. Overall, these results support the reliability and validity of the A-SHARP, and, as intended, the problem and provocation subscales appear to assess different constructs. However, much more work is needed to determine fully how well each of the subscales performs psychometrically.

The association between behavioural and emotional problems and age in adults with Down syndrome without dementia: Examining a wide spectrum of behavioural and emotional problems

The literature on the association between behavioural and emotional problems and ageing in adults with Down syndrome (DS) without dementia is limited and has generally not reported on a wide range of behavioural and emotional problems. This research aimed to extend the field by examining the associations between age and a wide spectrum of behavioural and emotional problems in adults with DS without dementia. A preliminary analysis of the association between potential covariates and behavioural and emotional problems was also undertaken. Parents and caregivers completed a questionnaire on behavioural and emotional problems for 53 adults with DS aged between 16 and 56 years. Twenty-eight adults with DS and their caregivers were part of a longitudinal sample, which provided two time points of data approximately four years apart. Additionally, 25 participants with DS and their caregivers were from a cross sectional sample, which provided one time point of data. Random effects regression analyses were used to examine the patterns in item scores for behavioural and emotional problems associated with age. No significant associations between age and the range or severity of any behavioural and emotional items were found. This suggested a more positive pattern for ageing adults with DS than has been previously described. Given that behavioural and emotional problems were not associated with age, investigation into other factors that may be associated with the behavioural and emotional difficulties for adults with DS is discussed.

Self-injury and aggression in tuberous sclerosis complex: cross syndrome comparison and associated risk markers

BACKGROUND

Research reporting prevalence rates of self-injurious and aggressive behaviour in people with tuberous sclerosis complex (TSC) is limited. No studies have compared rates of these behaviours in TSC with those in other syndrome groups matched for degree of disability or investigated risk markers for these behaviours in TSC.

METHODS

Data from the Challenging Behaviour Questionnaire were collected for 37 children, aged 4 to 15 years, with TSC. Odds ratios were used to compare rates of self-injury and aggression in children with TSC with children with idiopathic autism spectrum disorder (ASD), fragile X, Cornelia de Lange and Down syndromes. Characteristics were measured using the Mood Interest and Pleasure Questionnaire, the Activity Questionnaire, the Social Communication Questionnaire, the Repetitive Behaviour Questionnaire, the Wessex Behaviour Schedule and the revised Non-communicating Children Pain Checklist. Mann-Whitney U analyses were used to compare characteristics between individuals with self-injury and aggression and those not showing these behaviours.

RESULTS

Rates of self-injury and aggression in TSC were 27% and 50%, respectively. These are high but not significantly different from rates in children with Down syndrome or other syndrome groups. Both self-injury and aggression were associated with stereotyped and pain-related behaviours, low mood, hyperactivity, impulsivity and repetitive use of language. Children who engaged in self-injury also had lower levels of interest and pleasure and showed a greater degree of 'insistence on sameness' than children who did not self-injure. Aggression was associated with repetitive behaviour. The majority of these associations remained significant when the association with level of adaptive functioning was controlled for.

CONCLUSIONS

Behavioural profiles can be used to identify those most at risk of developing self-injury and aggression. Further research is warranted to understand the influence of such internal factors as mood, ASD symptomatology and pain on challenging behaviour in people with intellectual disability.

The prevalence of aggression in genetic syndromes: a review

Research into behavioural phenotypes identifies both environmental and organic factors as influencing aggression in children and adults with genetic disorders associated with intellectual disability. However, in contrast to self-injury there is a paucity of research that compares aggression across relevant syndromes. The primary aim of this review is to examine the association between aggression and genetic syndromes by analysis of prevalence studies. The review also examines the literature on the form of the behaviour and influence of environmental factors. Results imply that certain syndrome groups (Cri du Chat, Smith-Magenis, Prader-Willi, Angelman, Cornelia de Lange, and Fragile X syndromes; estimates over 70%) evidence a stronger association with aggression than others (e.g. Williams and Down syndromes; estimates below 15%). However, the strength of association is difficult to quantify due to methodological differences between studies. The results from examining form and environmental influences highlight the importance of phenotype-environment interactions. Research employing group comparison designs is warranted and future work on the assessment and intervention of aggression in genetic syndromes should consider the importance of phenotype-environment interactions.

Fragile X syndrome: lifespan developmental implications for those without as well as with intellectual disability

PURPOSE OF REVIEW

Advances in developmental neuropsychiatry and the mental health needs of people with intellectual disability are creating ever greater understanding of the critical associations between human genome variations and psychological functioning throughout lifespan and across the entire intellectual ability spectrum. This review highlights the recent developments and their clinical implications for people with fragile X syndrome.

RECENT FINDINGS

There is substantial evidence for individuals of all ages and intellectual abilities being prone to psychological profiles determined not only by having a fragile X gene full mutation, but also by having premutations and intermediate alleles. The importance of these genetic contributors to mental life, if anything, increases with age. Premutation carriers are prone to neurodegenerative mid-life fragile X tremor-ataxia syndrome. Women with premutations experience premature ovarian insufficiency. Imbalances in the (gamma amino butyrie acid)-glutamate mediated postsynaptic cascade central neuronal pathways are a current focus of psychopharmacological enquiry, giving the hope of syndrome-specific medical treatments.

SUMMARY

Findings from genetic, neurological, biochemical, psychological and pharmacological research are combining to revolutionize understanding of the pathogenesis of developmental and psychological disabilities affecting individuals with fragile X syndrome irrespective of age, intelligence level and gene mutation status. Results of syndrome-specific medication trials are awaited.

A review of defining and measuring sociability in children with intellectual disabilities

There is a substantial body of research indicating that compromised social functioning for individuals with intellectual disabilities has far reaching implications for quality of life, community participation and wellbeing. However, an inherent difficulty for research into social functioning is the lack of agreed definition of key concepts in the area. The current paper reviews definitions for four concepts related to the central concept of sociability (social cognition, social competence, social skills and social behaviour). By reviewing the definitions available in the wider social and cognitive psychology literature and comparing these to definitions provided in research with individuals with intellectual disabilities it is clear that concepts are poorly defined. The current article proposes working definitions which may be used give impetus to future debate in the area. The clinical implications of having implicitly understood concepts rather than definable and measurable traits are considered. The review calls for researchers to provide definitions for the concepts under investigation and their relationship to measures employed in research.

Epidemiology of mental ill health in adults with intellectual disabilities

PURPOSE OF REVIEW

Adults with intellectual disabilities experience higher rates of mental ill health than the general population. Despite this, the epidemiological knowledge base remains limited. The purpose of this article is to review mental health epidemiological studies relevant to adults with intellectual disabilities, published since January 2008.

RECENT FINDINGS

Several studies have aimed to build the epidemiological evidence base, particularly with regards to problem behaviours, which appear to be remitting-relapsing conditions rather than necessarily being chronic. Most of such work confirms prevalence and incidence rates, and conducts exploratory analyses to determine factors independently related to mental ill health. Down syndrome protects against problem behaviours and mental ill health (except dementia that occurs at a higher rate), whereas epilepsy does not appear to affect risk for mental ill health. Dementia is four times more common in older persons with intellectual disabilities without Down syndrome than in the general population. Persons with borderline intellectual disabilities also experience higher rates of mental ill health than the general population, but receive fewer treatments.

SUMMARY

This work builds usefully upon previous studies. Further hypothesis-based analyses are needed.

Relationship among challenging, repetitive, and communicative behaviors in children with severe intellectual disabilities

We used experimental and descriptive functional analyses and lag sequential analyses to examine the functional and temporal relationship among the self-injurious (SIB), potentially injurious, repetitive, challenging, and pragmatic communicative behaviors of 6 children with intellectual disabilities. Functional analyses revealed social function for SIB, potentially injurious, and repetitive behaviors across 5, 4, and 5 participants, respectively. Sixteen functionally equivalent response classes were identified across participants using both experimental and naturalistic observation data. Repetitive, potentially injurious, and SIB behaviors were significantly temporally associated, and pragmatic communicative behaviors were strongly temporally associated with challenging behaviors. The importance of the temporal and functional relationship between imperative communicative acts and challenging behavior is discussed.

Language Characteristics of Individuals with Down Syndrome

On average, language and communication characteristics of individuals with Down syndrome (the most common genetic cause of intellectual disability) follow a consistent profile. Despite considerable individual variability, receptive language is typically stronger than expressive language, with particular challenges in phonology and syntax. We review the literature on language and literacy skills of individuals with Down syndrome, with emphasis on the areas of phonology, vocabulary, syntax, and pragmatics. We begin by describing the hearing, oral-motor, cognitive, social, and prelinguistic and early nonverbal communication characteristics of individuals with Down syndrome. We conclude with a discussion of clinical implications and research directions.

Prevalence of, and factors associated with, problem behaviors in adults with intellectual disabilities

This study aimed to determine the prevalence of problem behaviors in adults with intellectual disabilities and to investigate which factors are independently associated with problem behaviors. A population-based cohort (n = 1023) had comprehensive individual assessments. Data were examined using multivariate logistic regression. The prevalence of problem behaviors was 22.5% (psychiatrists' opinion) or 18.7% (DC-LD criteria). Factors independently associated with problem behaviors were lower ability level, female gender, living in a congregate care setting or with paid carer support (rather than living with a family carer), having urinary incontinence; visual impairment, not having Down syndrome, and not having severe physical disabilities. Further studies focusing on the etiology, course, and treatment of problem behaviors are required.

Mental retardation and associated neurological dysfunctions in Down syndrome: a consequence of dysregulation in critical chromosome 21 genes and associated molecular pathways

Down syndrome (DS), affecting 1/700 live births, is the major genetic cause of mental retardation (MR), a cognitive disorder with hard impact on public health. DS brain is characterized by a reduced cerebellar volume and number of granular cells, defective cortical lamination and reduced cortical neurons, malformed dendritic trees and spines, and abnormal synapses. These neurological alterations, also found in trisomic mouse models, result from gene-dosage effects of Human Chromosome 21 (HC21) on the expression of critical developmental genes. HC21 sequencing, mouse ortholog gene identification and DS mouse model generation lead to determine HC21 gene functions and the effects of protein-dosage alterations in neurodevelopmental and metabolic pathways in DS individuals. Trisomic brain transcriptome of DS patients and trisomic mouse models identified some molecular changes determined by gene-overdosage and associated dysregulation of some disomic gene expression in DS brains. These transcriptional variations cause developmental alterations in neural patterning and signal transduction pathways that may lead to defective neuronal circuits responsible for the pathogenesis of MR in DS. Recently, the first altered molecular pathway responsible of some DS phenotypes, including neurological and cognitive disorders has been identified. In this pathway, two critical HC21 genes (DYRK1A and DSCR1) act synergistically to control the phosphorylation levels of NFATc and NFATc-regulated gene expression. Interestingly, the NFATc mice show neurological dysfunctions similar to those seen in DS patients and trisomic mouse models. Treatment of DS mouse model Ts65Dn with GABA(A) antagonists allowed post-drug rescue of cognitive defects, indicating a hopeful direction in clinical therapies for MR in children with DS.

The prevalence and incidence of mental ill-health in adults with Down syndrome

BACKGROUND

While there is considerable literature on adults with Down syndrome who have dementia, there is little published on the epidemiology of other types of mental ill-health in this population.

METHOD

Longitudinal cohort study of adults with Down syndrome who received detailed psychiatric assessment (n = 186 at the first time point; n = 134 at the second time point, 2 years later).

RESULTS

The prevalence of Down syndrome for the 16 years and over population was 5.9 per 10 000 general population. Point prevalence of mental ill-health of any type, excluding specific phobias, was 23.7% by clinical, 19.9% by Diagnostic Criteria for Psychiatric Disorders for use with Adults with Learning Disabilities/Mental Retardation (DC-LD), 11.3% by ICD-10 Classification of Mental and Behavioural Disorders: Diagnostic Criteria for Research (DCR-ICD-10) and 10.8% by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Revised (DSM-IV-TR) criteria. Two-year incidence of mental ill-health of any type was 14.9% by clinical and DC-LD, 9.0% by DCR-ICD-10 and 3.7% by DSM-IV-TR criteria. The highest incidence was for depressive episode (5.2%) and dementia/delirium (5.2%). Compared with persons with intellectual disabilities (ID) of all causes, the standardized rate for prevalence of mental ill-health was 0.6 (0.4-0.8), or 0.4 (0.3-0.6) if organic disorders are excluded, and the standardized incidence ratio for mental ill-health was 0.9 (0.6-1.4), or 0.7 (0.4-1.2) if organic disorders are excluded. Urinary incontinence was independently associated with mental ill-health, whereas other personal factors, lifestyle and supports, and other types of health needs and disabilities were not.

CONCLUSIONS

Mental ill-health is less prevalent in adults with Down syndrome than for other adults with ID. The pattern of associated factors differs from that is found for other adults with ID, with few associations found. This suggests that the protection against mental ill-health is biologically determined in this population, or that there are other factors protective for mental ill-health yet to be identified for the population with Down syndrome.

Grief and its complications in individuals with intellectual disability

Bereavement and loss have significant impact on the lives of individuals with intellectual disability (ID). Although there is a growing impetus to define the symptoms of grief that predict long-term functional impairment, little is known about maladaptive grieving among individuals with ID. We examine the literature concerning the phenomenology of traumatic grief (TG) in the general population, along with what is known about the manifestations of grief in individuals with ID. We then apply modern theories of grief and grief resolution to individuals with ID in order to highlight potential areas of vulnerability in this population and to lay the groundwork for interventions that will facilitate their adaptation to loss. We provide a theoretical framework for the proposition that individuals (including children and adults) with ID are more susceptible to TG, based on an increased risk of secondary loss, barriers to communicating about the loss, and difficulty finding meaning in the loss. We conclude that individuals with ID should be considered as potential candidates for targeted bereavement interventions. Further research is required, however, in order to develop population-appropriate measurement scales for testing these hypotheses.

Symptoms of dementia among adults with Down's syndrome: a qualitative study

BACKGROUND

Dementia is common among adults with Down's syndrome (DS); yet the diagnosis of dementia, particularly in its early stage, can be difficult in this population. One possible reason for this may be the different clinical manifestation of dementia among people with intellectual disabilities.

AIMS

The aim of this study was to map out the carers' perspective of symptoms of dementia among adults with DS in order to inform the development of an informant-rated screening questionnaire.

METHOD

Unconstrained information from carers of people with DS and dementia regarding the symptoms, particularly the early symptoms of dementia, was gathered using a qualitative methodology. Carers of 24 adults with DS and dementia were interviewed. The interviews were recorded and fully transcribed. The transcripts were then analysed using qualitative software.

RESULTS

There appeared to be many similarities in the clinical presentation of dementia in adults with DS and the non-intellectually disabled general population. Like in the non-intellectually disabled general population, forgetfulness especially, impairment of recent memory combined with a relatively intact distant memory and confusion were common, and presented early in dementia among adults with DS. However, many 'frontal lobe'-related symptoms that are usually manifested later in the process of dementia among the general population were common at an early stage of dementia among adults with DS. A general slowness including slowness in activities and speech, other language problems, loss of interest in activities, social withdrawal, balance problems, sleep problems, loss of pre-existing skills along with the emergence of emotional and behaviour problems were common among adults with DS in our study.

CONCLUSIONS

This study highlights the similarities in the clinical presentation of dementia among the general population and people with DS with a particular emphasis on the earlier appearance of symptoms associated with the frontal lobe dysfunction among adults with DS.

Social phenotypes in neurogenetic syndromes

Many of the known genetically based neurodevelopmental disorders are associated with a distinctive behavioral phenotype. As these behavioral phenotypes have been elucidated by clinical research, distinctive profiles of social traits have emerged as prominent syndromic features. This article reviews social phenotypic findings for fragile X syndrome, Down syndrome, Prader-Willi syndrome, Smith-Magenis syndrome, Turner syndrome, Williams syndrome, and velocardiofacial syndrome. An analysis of these social profiles raises several questions regarding the relationship between identified social impairments and autism and the relationship between social impairments in neurodevelopmental disorders and those found in normative child populations. The unique profile of certain of the known behavioral phenotypes also serves to distinguish several dimensions of sociability that are not readily observed in typical populations.

Physical aggression towards others in adults with learning disabilities: prevalence and associated factors

BACKGROUND

Many people with learning disabilities (LD) show aggressive behaviour, but the extent of the problem and its associated factors and effects are unclear.

METHODS

A cross-sectional analysis was carried out using interview data from 3065 adults with LD on the Leicestershire LD Register. Physical aggression towards others was defined as carers reporting frequent (more than three times per week) and/or severe episodes. Individuals with and without aggression were compared using multiple logistic regression models for potential physical and psychological factors.

RESULTS

Carers reported that 443 (14%) of adults were physically aggressive towards others. Men (P = 0.001), younger individuals (P < 0.001), people with more severe LD (P < 0.001) and those in institutional settings (P < 0.001) had a significantly higher prevalence of physical aggression. People with Down syndrome had a lower prevalence of physical aggression (P < 0.001). After adjustment, we found no relationship between aggression and the presence of epilepsy or autism. Among psychological factors, symptoms of frustration (P < 0.001) and mood swings (P < 0.001) were associated with higher levels of aggression. Failure to cope among carers was reported by 14% overall: 42% of people caring for adults with aggression said they were unable to cope compared with 10% of those caring for adults without aggression.

CONCLUSIONS

Physical aggression towards other people presents a significant challenge to carers of adults with LD. Further research is needed to identify aetiological factors with a view to finding effective interventions to reduce, and improve management of, this behaviour.

Spectrum of cognitive, behavioural and emotional problems in children and young adults with Down syndrome

In comparison to most other groups with intellectual disability individuals with Down syndrome are at lower risk for significant psychopathology, although relative to their typically developing peers they have higher rates of behavioural and emotional problems. A total of 43 Down syndrome patients (21 females and 22 males), who ranged in age from 5.33 to 30.58 years, were examined for the presence of age-related changes in the spectrum of externalizing and internalizing problems. Intelligence tests included Hamburg-Wechsler-Intelligenz Test für Kinder III (HAWIK-III), Hamburg-Wechsler-Intelligenz Test für Erwachsene (HAWIE-R) and Kaufman-Assessment-Battery for Children, German Version (K-ABC). Behavioural and emotional problems were assessed by the the Strengths and Difficulties Questionnaire for Parents, German Version (SDQ) and the Clinical Assessment Scale for Child and Adolescent Psychopathology (CASCAP). IQ was significantly inversly related to the age of patients. Externalizing behaviours (dominant, opposing/refusing, impulsiveness, inattention and increased motor activity) were significantly higher in the 5-10 years old group, whereas internalizing behaviours (shy/insecure, low self confidence, decreased motor activity) where more prevalent in adolescents and adults (10-30 years). Possible relationships between this age-related changes and increased risks of later-onset psychopathology (depression and dementia) are discussed.

Challenging behaviours should not be considered as depressive equivalents in individuals with intellectual disability

BACKGROUND

Depression is one of the most common forms of psychopathology in people with intellectual disability (ID). The present study evaluated the utility of an expanded assessment of psychiatric symptoms and challenging behaviours, as measured by the Clinical Behavior Checklist for Persons with Intellectual Disabilities (CBCPID).

METHODS

The CBCPID was administered to 92 people with ID, 35 of whom were diagnosed with a depressive disorder.

RESULTS

Item and factor analysis of the scale indicated that depression was best assessed using the core DSM-IV symptoms of depressive disorder. Challenging behaviours such as self-injury or aggression were not closely associated with depression. Short scales using the core DSM-IV symptoms of depression were highly internally consistent. There was also evidence of the validity of these scales.

CONCLUSIONS

This study found no evidence that challenging behaviours were depressive equivalents in this population. The present authors conclude that the assessment of depression in people with ID should focus on the core DSM-IV symptoms of depression.

Maladaptive behaviour in children and adolescents with Down's syndrome

BACKGROUND

Although children with Down's syndrome (DS) are at lower risk for psychopathology than others with intellectual disability, they do show more problems than typically developing children. However, age-related trends in these problems remain unclear.

METHODS

The present authors examined age-related changes in the maladaptive behaviours of 211 children and adolescents with DS aged between 4 and 19 years (mean = 9.74 years). Most participants (n = 180) were recruited from families residing in the greater Los Angeles area, California, USA, while a minority (n = 31) were patients from a clinic specializing in the psychiatric management of people with DS. The participants were divided into four age groups: (1) 4-6 years, (2) 7-9 years, (3) 10-13 years and (4) 14-19 years.

RESULTS

Externalizing behaviours were lower across both the community and clinic samples, while internalizing behaviours were significantly higher in older adolescents aged between 14 and 19 years. Increases were found in withdrawal, seen in 63% of community-based adolescents, and 75% of clinic adolescents.

CONCLUSIONS

Older adolescents with DS may show decreased externalizing symptoms and subtle increases in withdrawal. Possible relationships are discussed between these shifts and increased risks of later-onset depression and Alzheimer's disease in adults with DS.

Aspectos genéticos e sociais da sexualidade em pessoas com síndrome de Down

As representações que pais e educadores fazem da sexualidade de pessoas com a síndrome de Down (SD) referem, muitas vezes, a atitudes agressivas ou, então, condutas assexuadas, exclusivamente fundamentadas na afetividade. Este trabalho faz uma análise da literatura referente à sexualidade e à reprodução em portadores dessa síndrome e avalia as possibilidades de recorrência do distúrbio a partir da segregação cromossômica em portadores de diferentes tipos de trissomia 21. Diversas publicações mostram a existência de diferentes níveis de maturidade e de adaptação social na SD que, associados a fatores como excesso de cuidados parentais, falta de amigos e preconceito social, constituem barreiras para a vivência plena da sexualidade. Os relatos de procriação em portadores da síndrome de Down revelam progênie normal ou com a síndrome, com maior prevalência de filhos normais. A análise de segregação cromossômica mostra probabilidade de 50% para conceptos com trissomia 21 e de 25% de filhos normais em casais com SD, caso os mesmos sejam férteis. O percentual restante corresponde a conceptos certamente inviáveis, com tetrassomia 21. Quando apenas um dos parceiros é portador da SD, a probabilidade de filhos normais ou com a síndrome passa para 50%. Nos casos de SD com trissomia por rearranjo estrutural como nas translocações 14/21 ou 21/21, a probabilidade de filhos normais é também de 50%. Portadores de mosaicismo podem apresentar riscos inferiores a esse percentual a depender da freqüência de células trissômicas no tecido gonadal. O direito à sexualidade e, por outro lado, o alto risco genético de recorrência da síndrome evidenciam não apenas a necessidade de se discutir a questão, como também a importância do apoio emocional e da educação sexual para a pessoa com SD.

An overview and update regarding medical problems in Down syndrome

Down syndrome is the commonest occurring syndrome, and because of the high risk of congenital heart disease, these children are frequently seen at cardiology clinics and wards. However, these individuals are also likely to have a variety of other-problems, both congenital and acquired, which may impinge on the medical and surgical management of cardiac problems. It is therefore important for the paediatric cardiology community to maintain a minimum level of expertise in other noncardiac aspects of the syndrome. This paper reviews Down syndrome, lists congenital and acquire disorders that may occur, and briefly addresses recent advances in the understanding of this condition.

Autism in Down's syndrome: a family history study

Several recent reports have described the occurrence of autism in subjects with Down's syndrome (DS). However, relatively little is known about the family history of these subjects, especially with reference to autism. In order to address this issue, the present author examined 11 subjects with DS and autism (DSM-III-R; nine males), and compared them with seven controls with DS but without autism (DSM-III-R; three males). Details about family psychiatric history were obtained from both groups with an emphasis on autism and related disorders. Subjects with both DS and autism had an excess of first-degree relatives who met the description of the broader phenotype of autism. Seven (64%) of the subjects with autism had an affected parent as against one (14%) of the control group. Similarly, four out of 11 siblings (36%) in the DS with autism group showed features suggestive of the broader autistic phenotype compared to none in the control group. These findings suggest that, at least in some cases, autism-specific genetic factors may be important even when autism occurs in the presence of known medical conditions. Further studies of the mechanism of comorbidity of autism with medical conditions may help clarify the aetiology of the disorder.

Behavioral phenotype of individuals with Down syndrome

Evidence is reviewed for a developmentally-emerging behavioral phenotype in individuals with Down syndrome that includes significant delay in nonverbal cognitive development accompanied by additional, specific deficits in speech, language production, and auditory short-term memory in infancy and childhood, but fewer adaptive behavior problems than individuals with other cognitive disabilities. Evidence of dementia emerges for up to half the individuals studied after age 50. Research issues affecting control group selection in establishing phenotypic characteristics are discussed, as well as the possible genetic mechanisms underlying variation in general cognitive delay, specific language impairment, and adult dementia. MRDD Research Reviews 2000;6:84-95. Wiley-Liss, Inc.

Comorbid Down's syndrome, Tourette syndrome and intellectual disability: registry prevalence and developmental course

The co-occurrence of Tourette syndrome (TS) and Down's syndrome (DS) has been previously reported in the literature. In the present study, a retrospective record review was conducted using the North Dakota TS registry in order to ascertain the number of cases of TS and DS, and to develop case descriptions. We identified five cases from North Dakota. Two of these patients were simply comorbid for TS and DS. One was additionally comorbid for bipolar disorder, another for childhood disintegrative disorder and a third had a D/G group translocation. The association between DS and TS occured in 2% of TS patients. Contrary to the situation in patients with pervasive developmental disorders, the presence of TS in DS may be a negative prognostic indicator.

Determinants of aggression, and adaptive and maladaptive behaviour in older people with Down's syndrome with and without dementia

In a cross-sectional study of aggression, and adaptive and maladaptive behaviour in 128 subjects with Down's syndrome (DS), 29 of whom had dementia, the current authors found that the presence of dementia was not predictive of aggression or maladaptive behaviour. However, the level of adaptive behaviour was shown to be lower in subjects with dementia, and in those with lower levels of cognitive functioning, as measured on a rating instrument, the Test for Severe Impairment. Although the presence of aggressive behaviours is not higher in subjects with dementia and DS on cross-sectional review, it remains to be seen whether aggression will increase in individual cases with the onset or progression of dementia. The decline in adaptive behaviour shown in the present study confirms the findings of previous studies and indicates a direction for service development for persons with the dual diagnosis of dementia and DS.

Fragile-X syndrome, Down's syndrome and autism: awareness and knowledge amongst special educators

Fragile-X syndrome is the commonest cause of inherited intellectual disability. There is good evidence for a behavioural phenotype. This has implications for school staff using standard educational techniques. Similarly, autism is known to create particular educational requirements. The present study examined the awareness and knowledge of fragile-X syndrome, Down's syndrome and autism amongst staff in special and mainstream education. One hundred and two special school staff and 40 mainstream school staff completed questionnaires. Most staff offered a variety of features 'typical' of Down's syndrome and autism. In contrast, staff knew less about fragile-X syndrome. Specific knowledge about the learning styles of these children was very poor, but was associated with having taught an affected child. Mainstream and special school staff offered similar levels of knowledge for all three conditions. Staff did not demonstrate a sufficiently specialized knowledge of fragile-X syndrome to ensure that the special educational needs of these children were being met fully.