Measurement tools for behaviours that challenge and behavioural function in people with intellectual disability: A systematic review and meta-analysis of internal consistency, inter-rater reliability, and test-retest reliability.

Behaviours that challenge (BtC) are common in people with intellectual disability (ID) and associated with negative long-term outcomes. Reliable characterisation of BtC and behavioural function is integral to person-centred interventions. This systematic review and meta-analytic study quantitatively synthesised the evidence-base for the internal consistency, inter-rater reliability, and test-retest reliability of measures of BtC and behavioural function in people with ID (PROSPERO: CRD42021239042). Web of Science, Embase, PsycINFO and MEDLINE were searched from inception to March 2024. Retrieved records (n = 3691) were screened independently to identify studies assessing eligible measurement properties in people with ID. Data extracted from 83 studies, across 29 measures, were synthesised in a series of random-effects meta-analyses. Subgroup analyses assessed the influence of methodological quality and study-level characteristics on pooled estimates. COSMIN criteria were used to evaluate the measurement properties of each measure. Pooled estimates ranged across measures: internal consistency (0.41-0.97), inter-rater reliability (0.29-0.93) and test-retest reliability (0.52-0.98). The quantity and quality of evidence varied substantially across measures; evidence was frequently unavailable or limited to a single study. Based on current evidence, candidate measures with the most evidence for internal consistency and reliability are discussed; however, continued assessment of measurement properties in ID populations is a key priority.

Diagnosis and management in Rubinstein-Taybi syndrome: first international consensus statement.

Rubinstein-Taybi syndrome (RTS) is an archetypical genetic syndrome that is characterised by intellectual disability, well-defined facial features, distal limb anomalies and atypical growth, among numerous other signs and symptoms. It is caused by variants in either of two genes (CREBBP, EP300) which encode for the proteins CBP and p300, which both have a function in transcription regulation and histone acetylation. As a group of international experts and national support groups dedicated to the syndrome, we realised that marked heterogeneity currently exists in clinical and molecular diagnostic approaches and care practices in various parts of the world. Here, we outline a series of recommendations that document the consensus of a group of international experts on clinical diagnostic criteria for types of RTS (RTS1: CREBBP; RTS2: EP300), molecular investigations, long-term management of various particular physical and behavioural issues and care planning. The recommendations as presented here will need to be evaluated for improvements to allow for continued optimisation of diagnostics and care.

Behaviours that Challenge in SATB2-associated Syndrome: Correlates of Self-injury, Aggression and Property Destruction.

SATB2-associated syndrome (SAS) is a genetic syndrome characterised by intellectual disability, severe speech delay, and palatal and dental problems. Behaviours that challenge (BtC) are reported frequently; however, there is limited research on specific forms of BtC and the correlates of these behaviours. The current study explores correlates of well-defined BtC, self-injury, aggression, and property destruction, in SAS. Eighty-one parents/caregivers of individuals with SAS (53.1% male, Mage 10.12 years) completed questionnaire measures of health, behavioural, emotional, and autism characteristics. Individuals with SAS were grouped based on caregiver responses to the presence or absence of self-injury, aggression, and property destruction on the Challenging Behaviour Questionnaire. Rates of self-injury, aggression and property destruction were 42%, 77% and 49%, respectively. Between-group comparisons were conducted to compare characteristics between behaviour groups. Significantly differing characteristics were entered into separate hierarchical logistic regressions for each form of BtC. Behavioural comparisons indicated variation in the characteristics associated with each behaviour. All hierarchical logistic regression models were significant (p < .001): self-injury (χ2(5) = 38.46, R2 = 0.571), aggression (χ2(4) = 25.12, R2 = 0.414), property destruction (χ2(4) = 23.70, R2 = 0.346), explaining between 34.6% and 57.1% of the variance in behaviour presence. This is the first study to identify correlates of self-injury, aggression, and property destruction in SAS. Variability in the characteristics associated with each behaviour highlights the importance of specificity when examining BtC. Understanding correlates of specific forms of BtC has important implications for informing SAS-associated pathways to behavioural outcomes and the implementation of tailored behavioural interventions.

'It wasn't the strategies on their own': Exploring caregivers' experiences of accessing services in the development of interventions for autistic people with intellectual disability.

LAY ABSTRACT: Many autistic individuals with intellectual disability experience anxiety, and for those who use few or no words, anxiety may present as behaviour that challenges, such as self-injury and avoiding anxiety-provoking situations. Families report difficulty accessing support from services for autistic individuals experiencing anxiety. Moreover, once receiving support, effective interventions for autistic people with intellectual disability are limited. We completed individual and group discussions with 16 caregivers of autistic people with intellectual disability, to (a) explore their experiences of accessing services for anxiety and/or behaviour that challenges for their child; and (b) understand what matters to caregivers when developing interventions that have been designed for them and the autistic individual with intellectual disability that they support. Caregivers reported that services, in their experience, did not deliver the support that they expected, and that they often needed to 'fight' for support. Caregivers considered services and families working together, the inclusion of peer support, and families being offered interventions that are flexible to individual circumstances to be important. These considerations are valuable for clinicians and researchers developing interventions and aiming to improve outcomes for autistic people with intellectual disability and their families.

Behavioural and physiological indicators of anxiety reflect shared and distinct profiles across individuals with neurogenetic syndromes.

Anxiety is heightened in individuals with intellectual disability, particularly in those with specific neurogenetic syndromes. Assessment of anxiety for these individuals is hampered by a lack of appropriate measures that cater for communication impairment, differences in presentation, and overlapping features with co-occurring conditions. Here, we adopt a multi-method approach to identify fine-grained behavioural and physiological (via salivary cortisol) responses to anxiety presses in people with fragile X (FXS; n = 27; Mage = 20.11 years; range 6.32 - 47.04 years) and Cornelia de Lange syndromes (CdLS; n = 27; Mage = 18.42 years; range 4.28 - 41.08 years), two neurogenetic groups at high risk for anxiety, compared to neurotypical children (NT; n = 21; Mage = 5.97 years; range 4.34 - 7.30 years). Results indicate that physical avoidance of feared stimuli and proximity seeking to a familiar adult are prominent behavioural indicators of anxiety/stress in FXS and CdLS. Heightened pervasive physiological arousal was identified in these groups via salivary cortisol. An association between autistic characteristics and anxiety was evident in the FXS group but not in the CdLS group pointing to syndrome-specific nuances in the association between anxiety and autism. This study furthers understanding of the behavioural and physiological presentation of anxiety in individuals with intellectual disability and progresses theoretical developments regarding the development and maintenance of anxiety at the intersection of autism.

Profiles of autism characteristics in thirteen genetic syndromes: a machine learning approach.

BACKGROUND: Phenotypic studies have identified distinct patterns of autistic characteristics in genetic syndromes associated with intellectual disability (ID), leading to diagnostic uncertainty and compromised access to autism-related support. Previous research has tended to include small samples and diverse measures, which limits the generalisability of findings. In this study, we generated detailed profiles of autistic characteristics in a large sample of > 1500 individuals with rare genetic syndromes. METHODS: Profiles of autistic characteristics based on the Social Communication Questionnaire (SCQ) scores were generated for thirteen genetic syndrome groups (Angelman n = 154, Cri du Chat n = 75, Cornelia de Lange n = 199, fragile X n = 297, Prader-Willi n = 278, Lowe n = 89, Smith-Magenis n = 54, Down n = 135, Sotos n = 40, Rubinstein-Taybi n = 102, 1p36 deletion n = 41, tuberous sclerosis complex n = 83 and Phelan-McDermid n = 35 syndromes). It was hypothesised that each syndrome group would evidence a degree of specificity in autistic characteristics. To test this hypothesis, a classification algorithm via support vector machine (SVM) learning was applied to scores from over 1500 individuals diagnosed with one of the thirteen genetic syndromes and autistic individuals who did not have a known genetic syndrome (ASD; n = 254). Self-help skills were included as an additional predictor. RESULTS: Genetic syndromes were associated with different but overlapping autism-related profiles, indicated by the substantial accuracy of the entire, multiclass SVM model (55% correctly classified individuals). Syndrome groups such as Angelman, fragile X, Prader-Willi, Rubinstein-Taybi and Cornelia de Lange showed greater phenotypic specificity than groups such as Cri du Chat, Lowe, Smith-Magenis, tuberous sclerosis complex, Sotos and Phelan-McDermid. The inclusion of the ASD reference group and self-help skills did not change the model accuracy. LIMITATIONS: The key limitations of our study include a cross-sectional design, reliance on a screening tool which focuses primarily on social communication skills and imbalanced sample size across syndrome groups. CONCLUSIONS: These findings replicate and extend previous work, demonstrating syndrome-specific profiles of autistic characteristics in people with genetic syndromes compared to autistic individuals without a genetic syndrome. This work calls for greater precision of assessment of autistic characteristics in individuals with genetic syndromes associated with ID.

The Executive Function Account of Repetitive Behavior: Evidence From Rubinstein-Taybi Syndrome.

In this study, we focus on Rubinstein-Taybi syndrome (RTS) to explore the associations between executive function deficits and repetitive behaviors. Thirty individuals with RTS completed direct assessments of inhibition, working memory and set-shifting. Informants completed repetitive behavior and executive function questionnaires. Repetitive questions were associated with poorer inhibition and working memory. Stereotypy was associated with poorer inhibition. Adherence to routines was associated with poorer set-shifting, but only on the parental report measure. No other associations were evident. There is evidence of an association between specific repetitive behaviors and executive functioning in RTS, suggesting executive dysfunction may underpin behavioral difference in RTS. The findings point towards specific associations that are of interest for further research across populations in which repetitive behaviors are present.

Utilising Interview Methodology to Inform the Development of New Clinical Assessment Tools for Anxiety in Autistic Individuals Who Speak Few or no Words.

Autistic individuals with intellectual disability who speak few or no words are at high risk of anxiety but are underrepresented in research. This study aimed to describe the presentation of anxiety in this population and discuss implications for the development of assessments. Interviews were conducted with 21 parents/carers of autistic individuals and nine clinicians. Data were analysed using content analysis and interpretative phenomenological analysis. Anxiety behaviours described by parents/carers included increased vocalisation, avoidance and behaviours that challenge. Changes to routine were highlighted as triggering anxiety. Clinicians discussed the importance of identifying an individual's baseline of behaviour, knowing an individual well and ruling out other forms of distress. This study raises considerations for early identification of anxiety and for subsequent support.

Divergent presentation of anxiety in high-risk groups within the intellectual disability population.

BACKGROUND: Anxiety symptomatology is common in individuals with intellectual disability (ID). Symptomatology includes both traditional Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) anxiety disorders and autism spectrum disorder (ASD)-related anxiety traits. Some genetic disorders such as Cornelia de Lange (CdLS) and fragile X syndromes (FXS) are at very high risk of anxiety and afford the opportunity to examine prevalence, profiles and associated person characteristics. However, prevalence and associated characteristics of anxiety in these high-risk groups remain poorly described and understood. The aim of the current study was to examine the prevalence and profile of DSM-5 and ASD-related anxiety symptomatology in individuals with CdLS and FXS and associated behavioural and cognitive characteristics. METHODS: Questionnaires and interviews assessing DSM-5 and ASD-related anxiety were conducted with caregivers of individuals with CdLS (n = 49) and FXS (n = 36). RESULTS: DSM-5 anxiety symptomatology was present in both groups with high co-morbidity across anxiety diagnoses. ASD-related anxiety was also prevalent with specific difficulties related to intolerance of uncertainty identified in both groups. Symptomatology was persistent over the lifespan for both groups. Anxiety type was partially associated with repetitive behaviour but not measures of overall ASD phenomenology in CdLS. CONCLUSIONS: DSM-5 and ASD-related anxiety are common in these high-risk syndromes associated with ID. Prospective syndrome specific presentations and associations, which may implicate specific underlying mechanisms, are discussed. Clinicians should be aware of the risk and difficulties involved in assessment of anxiety in individuals with ID, including atypical types, to ensure these individuals do not "miss" diagnoses and support in general clinical practice.

Phenotypic characteristics and variability in CHARGE syndrome: a PRISMA compliant systematic review and meta-analysis.

BACKGROUND: CHARGE syndrome (OMIM #214800) is a phenotypically complex genetic condition characterised by multi-system, multi-sensory impairments. Behavioural, psychological, cognitive and sleep difficulties are not well delineated and are likely associated with biopsychosocial factors. METHODS: This meta-analysis investigated the prevalence of clinical features, physical characteristics and conditions, behavioural, psychological, cognitive and sleep characteristics in CHARGE syndrome, and statistically evaluated directional associations between these characteristics. Pooled prevalence estimates were calculated using reliable, prespecified quality weighting criteria, and meta-regression was conducted to identify associations between characteristics. RESULTS: Of the 42 eligible studies, data could be extracted for 1675 participants. Prevalence estimates were highest for developmental delay (84%), intellectual disability (64%), aggressive behaviour (48%), self-injurious behaviour (44%) and sleep difficulties (45%). Meta-regression indicated significant associations between intellectual disability and choanal atresia, intellectual disability and inner ear anomalies, sleep difficulties and growth deficiency, and sleep difficulties and gross motor difficulties. CONCLUSIONS: Our comprehensive review of clinical features, behavioural, psychological, cognitive and physical characteristics, conditions and comorbidities in CHARGE syndrome provides an empirically based foundation to further research and practice.

The behavioral phenotype of Rubinstein-Taybi syndrome: A scoping review of the literature.

Rubinstein-Taybi syndrome (RTS) is a rare genetic syndrome associated with growth delay, phenotypic facial characteristics, microcephaly, developmental delay, broad thumbs, and big toes. Most research on RTS has focused on the genotype and physical phenotype; however, several studies have described behavioral, cognitive, social, and emotional characteristics, elucidating the behavioral phenotype of RTS. The reporting of this review was informed by PRISMA guidelines. A systematic search of CINAHL, Medline, and PsychINFO was carried out in March 2021 to identify group studies describing behavioral, cognitive, emotional, psychiatric, and social characteristics in RTS. The studies were quality appraised. Characteristics reported include repetitive behavior, behaviors that challenge, intellectual disability, mental health difficulties, autism characteristics, and heightened sociability. Findings were largely consistent across studies, indicating that many characteristics are likely to form part of the behavioral phenotype of RTS. However, methodological limitations, such as a lack of appropriate comparison groups and inconsistency in measurement weaken these conclusions. There is a need for multi-disciplinary studies, combining genetic and psychological measurement expertise within single research studies. Recommendations are made for future research studies in RTS.

Prevalence of anxiety symptomatology and diagnosis in syndromic intellectual disability: A systematic review and meta-analysis.

Individuals with syndromic intellectual disability are at increased risk of experiencing anxiety. Comparing prevalence estimates of anxiety will allow the identification of at-risk groups and inform causal pathways of anxiety. No known study has explored estimates of anxiety symptomatology and diagnosis, including specific anxiety profiles, across groups whilst accounting for methodological quality of studies. This systematic review and meta-analysis aimed to fill this gap. Prior to review completion, methodology and analysis plans were registered and documented in a protocol (CRD42019123561). Data from 83 papers, involving a pooled sample of 13,708 across eight syndromes were synthesised using a random effects model. Anxiety prevalence ranged from 9 % (95 % CI: 4-14) in Down syndrome to 73% in Rett syndrome (95 % CI: 70-77). Anxiety prevalence across syndromic intellectual disability was higher than for intellectual disability of mixed aetiology and general population estimates. Substantial variability between syndromes identified groups at higher risk than others. The identification of high-risk groups is crucial for early intervention, allowing us to refine models of risk and identify divergent profiles.

The behavioural phenotype of SATB2-associated syndrome: a within-group and cross-syndrome analysis.

BACKGROUND: SATB2-associated syndrome (SAS) is a multisystem neurodevelopmental disorder characterised by intellectual disability, speech delay, and craniofacial anomalies. Although the clinical presentation of SAS is well-delineated, behaviours associated with SAS are less well-defined. Given the varied social profile reported in SAS of a 'jovial' predisposition and autistic behaviours, there may be phenotypic overlap with both Angelman syndrome (AS) and non-syndromal autism. This study aimed to describe behaviours in SAS in relation to chronological age and level of ability and contrast aspects of the behavioural phenotype with AS and non-syndromal autism. METHODS: Informant report questionnaire measures of behaviour, emotion, and autism characteristics were completed for 81 individuals with SAS (aged 1-36 years; 43 male). Within-group associations were analysed, and categorical data were compared between pre-school (1-5 years), school-age (6-15 years), and adolescent and adult SAS sub-groups (16 years and over). Cross-syndrome subscale and item-level analyses were conducted for 63 individuals with SAS (aged 1-27 years; 31 male), who were matched according to age and level of ability to 63 individuals with AS (aged 2-25 years; 32 male) and 63 individuals with non-syndromal autism (aged 3-26 years; 53 male). RESULTS: In SAS, higher rates of overactivity were moderately associated with lower self-help ability, and higher general anxiety scores were reported for males compared with females. Cross-syndrome subscale analyses uncovered several significant differences (p < .01), with comparatively low rates of stereotyped behaviour, overactivity, insistence on sameness and positive affect, and comparatively greater interest and pleasure and compulsive behaviour in individuals with SAS. Item-level analyses revealed a distinct profile of repetitive and autistic behaviours. LIMITATIONS: Developmental analysis was based on a cross-sectional rather than a longitudinal research design, the contribution of pain and sleep to behaviour was not explored, and molecular genetic testing to determine genotype-phenotype behavioural relationships was not possible. CONCLUSIONS: This study highlights the importance of behavioural comparisons to well-delineated groups and the utility of fine-grained item-level analyses to elucidate aspects of behaviour that might be syndrome related or shared across neurodevelopmental disorders. Future research is needed to further describe the distinctive repetitive and autistic behavioural phenotype in SAS.

Executive function, repetitive behaviour and restricted interests in neurodevelopmental disorders.

BACKGROUND: Individuals with genetic syndromes show unique profiles of repetitive behaviours and restricted interests (RRBs). The executive dysfunction account of RRBs suggests that in autistic (AUT) individuals executive function impairments underpin RRBs, but not communication and social interaction autistic characteristics. AIMS: To 1) describe profiles of behavioural manifestations of executive function (EF behaviours) and 2) explore the relationship between EF behaviours and autistic traits across individuals with Cornelia de Lange (CdLS), fragile X (FXS) and Rubinstein-Taybi syndromes (RTS), and AUT individuals. METHOD: Carers completed the Behavior Rating Inventory of Executive Function - Preschool Version and the Social Communication Questionnaire. Data reporting on 25 individuals with CdLS (Mage = 18.60, SD = 8.94), 25 with FXS (Mage = 18.48, SD = 8.80), 25 with RTS (Mage = 18.60, SD = 8.65) and 25 AUT individuals (Mage = 18.52, SD = 8.65) matched on chronological age and adaptive ability were included in analyses. RESULTS: All groups showed impairments across EF behaviours compared to two-to-three-year-old typically developing normative samples with no differences between groups. Different EF behaviours predicted RRBs in the syndrome groups with no associations found in the AUT group. CONCLUSIONS: Syndrome related differences should be considered when developing targeted interventions that focus on EF behaviours and/or RRBs in these groups.

Anxiety characteristics in individuals with Williams syndrome.

BACKGROUND: Williams syndrome anxiety research predominantly focuses on disorder prevalence and symptomatology, categorised using standardised mental health classifications. However, the use of these assessments may not fully capture the phenotypic features of anxiety in Williams syndrome. In this study, we examined characteristics of anxiety using a formulation framework. METHOD: A semi-structured interview was conducted with thirteen parents of individuals with Williams syndrome (median age: 19, age range: 12-45, 8 females). RESULTS: Various anxiety triggers were reported, including anxiety triggered by phobias, uncertainty and negative emotions in others. The range of described behaviours was diverse with both avoidant and active coping strategies for anxiety management reported. CONCLUSIONS: Many of the characteristics described were consistent with findings in the intellectual disability and typically developing literature, although novel information was identified. The study demonstrates the utility of a formulation framework to explore anxiety characteristics in atypical populations and has outlined new avenues for research.

Anxiety and intellectual functioning in autistic children: A systematic review and meta-analysis.

LAY ABSTRACT: Autistic children often experience higher levels of anxiety than their peers. It can be difficult to diagnose and treat anxiety disorders in autistic children, in part because of the high degree of variability in their underlying abilities and presentations. Some evidence suggests that autistic children with higher intelligence (as measured by intelligence quotient) experience higher levels of anxiety than autistic children with lower intelligence. However, the evidence is inconsistent, with other papers not finding a difference or finding higher levels of anxiety in autistic children with lower intelligence. In this article, we review existing literature to see whether autistic children with higher intelligence quotients have higher anxiety than autistic children with lower intelligence quotients. A systematic search of the literature was conducted which identified 49 papers on the topic. The methods of all the papers were reviewed using an objective quality assessment framework. When combining the data statistically, there was evidence that autistic children with higher intelligence quotients are more anxious than autistic children with lower intelligence quotients. The quality review raised common weaknesses across studies. Most importantly, few studies used measures of anxiety that have been shown to be valid for children with very low intelligence quotients. Similarly, many studies used measures of anxiety that have not been shown to be valid for autistic children. These factors are important because autistic children and those with low intelligence quotient may experience or understand anxiety differently. Future research should use fully validated measures to test whether high intelligence quotient is associated with high levels of anxiety in autistic children.

Anxiety in autistic individuals who speak few or no words: A qualitative study of parental experience and anxiety management.

LAY ABSTRACT: Anxiety is a common condition in autistic individuals, including those who also have an intellectual disability. Despite this, autistic individuals who have severe to profound intellectual disability, or use few or no words, are often excluded from autism research. There are also very few assessment tools and interventions with known effectiveness for autistic individuals with intellectual disability. In this study, we aimed to learn more about parent/carers experiences of recognising and managing anxiety in autistic individuals who use few or no words. We conducted semi-structured interviews with parents and carers to address three research questions: (1) what techniques and management strategies do parents describe for anxiety-related behaviour in their child; (2) how do communication difficulties impact parental understanding and management of anxiety provoking situations and behaviours; (3) what is the impact of anxiety-related behaviours on the quality of life of autistic individuals and their families? During the interviews, parents described difficulties recognising anxiety in their child, mostly due to reduced verbal language use and anxiety behaviours overlapping with other behaviours (e.g. autism characteristics). However, parents also described use of a number of management strategies, including some which overlap with components of evidence-based interventions for emotional and behavioural problems in autistic individuals (e.g. exposure/sensory calming). Despite this, parents reported that anxiety continues to have significant impact on quality of life. We will use the findings of this study to inform future research to develop assessment tools and interventions for anxiety in autistic individuals who use few or no words.

Scaling of Early Social Cognitive Skills in Typically Developing Infants and Children with Autism Spectrum Disorder.

We delineate the sequence that typically developing infants pass tasks that assess different early social cognitive skills considered precursors to theory-of-mind abilities. We compared this normative sequence to performance on these tasks in a group of autistic (AUT) children. 86 infants were administered seven tasks assessing intention reading and shared intentionality (Study 1). Infants responses followed a consistent developmental sequence, forming a four-stage scale. These tasks were administered to 21 AUT children (Study 2), who passed tasks in the same sequence. However, performance on tasks that required following others' eye gaze and cooperating with others was delayed. Findings indicate that earlier-developing skills provide a foundation for later-developing skills, and difficulties in acquiring some early social cognitive skills in AUT children.

Temper outbursts in Lowe syndrome: Characteristics, sequence, environmental context and comparison to Prader-Willi syndrome.

BACKGROUND: There is limited research into the nature and aetiology of temper outbursts in people with intellectual disabilities. In this study, we describe the phenomenology and environmental context of temper outbursts in Lowe syndrome, a rare genetic syndrome in which outbursts are purportedly frequent. METHOD: A temper outburst interview (TOI) was conducted with caregivers of seventeen individuals with Lowe syndrome to generate an account of the behavioural sequence, common antecedents and consequences of temper outbursts, and to enable comparisons with similar work on Prader-Willi syndrome. RESULTS: Outbursts in Lowe syndrome were frequently triggered by thwarted goal-directed behaviour and were associated with high levels of physical aggression and property destruction. CONCLUSIONS: Form and sequence of outbursts showed similarities to Prader-Willi syndrome and to behaviours reported in literature on typically developing children. The results highlight the importance of considering shared aetiology as well as syndrome-specific pathways in the development of outbursts.

Williams syndrome: recent advances in our understanding of cognitive, social and psychological functioning.

PURPOSE OF REVIEW: Since the last review of Williams syndrome in Current Opinion (2001) there have been many advances in knowledge about the cognitive, social and psychological impairments that characterize the disorder. The present review focuses on current research in these areas. RECENT FINDINGS: Williams syndrome is associated with a wide range of cognitive, linguistic, social and other difficulties. When young, these deficits may appear relatively mild - for example, many children are highly sociable and talkative - but with age the impact of these difficulties becomes more evident. Thus, inappropriate social behaviours can significantly increase the risk of social exclusion and vulnerability to abuse. Their superficially good speech can lead to educational and other services failing to understand the true extent of impairments or the need for specialist support. Mental health problems, especially related to anxiety, often become an increasing challenge from adolescence onwards. SUMMARY: The core difficulties associated with Williams syndrome have a cascading effect on many areas of development over time. However, specialist provision is rare and intervention trials are almost nonexistent. Longitudinal research is needed to identify factors associated with cognitive, social and emotional problems and to develop more effective ways of minimizing and treating difficulties.