The prevalence and phenomenology of self-injurious and aggressive behaviour in genetic syndromes.

BACKGROUND: Self-injurious and aggressive behaviours are reported as components of some behavioural phenotypes but there are few studies comparing across syndrome groups. In this study we examined the prevalence of these behaviours and the associated person characteristics in seven genetic syndromes. METHODS: Questionnaire data on self-injury and aggression, mood, hyperactivity, autism spectrum disorder and repetitive behaviour were collected on Angelman (AS, n=104), Cornelia de Lange (CdLS, 101), Cri du Chat (CdCS, 58), Fragile X (FXS, 191), Lowe (LS, 56), Prader-Willi (PWS, 189) and Smith-Magenis (SMS, 42) syndromes. RESULTS: A significantly higher prevalence of self-injury was evident in CdCS, CdLS, FXS, PWS, LS and SMS. The prevalence of aggression was significantly heightened in AS and SMS. Self-injury was associated with repetitive and impulsive behaviour in CdLS, FXS, PWS and LS. Impulsivity and overactivity were significantly higher in those showing aggression across all syndrome groups. CONCLUSIONS: These data quantify the risk for self-injury and aggression in the syndromes studied with implications for early intervention. The associations between these behaviours and person characteristics both within and between syndromes warrant further research.

The association between repetitive behaviours, impulsivity and hyperactivity in people with intellectual disability.

BACKGROUND: There is a need for assessments of psychological difference and disorder in people who have more severe intellectual disability (ID). Hyperactivity and impulsivity are two behavioural domains of importance as they are correlated with self-injury and aggression and this alludes to a shared cognitive correlate of compromised behavioural inhibition. Additionally, compromised behavioural inhibition is demonstrably related to repetitive behaviour and the latter might be expected to be associated with impulsivity and hyperactivity. METHODS: The Activity Questionnaire (TAQ) was developed for this study. Three sub-scales with high levels of face validity were supported by factor analysis of the scoring of 755 intellectually disabled participants on the TAQ items. These sub-scales mapped onto the constructs of Overactivity, Impulsivity and Impulsive Speech. Test-retest, inter-rater reliability and internal consistency were robust. TAQ scores and scores on the Repetitive Behaviour Questionnaire (RBQ) were collected for a sample of 136 participants with varying degrees of ID. RESULTS: Scores on the TAQ at sub-scale and full-scale level were not related to level of adaptive functioning. There were significant positive associations between overactivity (TAQ) and stereotyped behaviour (RBQ), impulsivity (TAQ) and restricted preferences (RBQ), and impulsive speech (TAQ) and repetitive speech (RBQ). CONCLUSIONS: The TAQ is a reliable assessment of hyperactivity and impulsivity for people with ID with robust factor structure. Validity requires evaluation. The relationship between impulsivity and restricted preferences may result from a common cognitive impairment in inhibition, which may underpin these two classes of behaviour.

Self-injurious behaviour in Cornelia de Lange syndrome: 1. Prevalence and phenomenology.

BACKGROUND: Self-injurious behaviour is frequently identified as part of the behavioural phenotype of Cornelia de Lange syndrome (CdLS). We conducted a case-control study of the prevalence and phenomenology of self-injurious behaviour (SIB) in CdLS. METHODS: A total of 54 participants with CdLS were compared with 46 individuals who were comparable on key variables including age, degree of intellectual disability and wheelchair use, using questionnaire and observational measures. RESULTS: Clinically significant self-injury was not more prevalent in the CdLS group (55.6%), nor was it different in presentation from that seen in the comparison group. Hyperactivity, stereotyped and compulsive behaviours predicted clinically significant self-injury in all participants. Hand directed, mild self-injury was more prevalent in CdLS. CONCLUSIONS: The results show that clinically significant self-injury may not be part of the behavioural phenotype of CdLS but a specific body target for proto-SIB is more common.

Self-injurious behaviour in Cornelia de Lange syndrome: 2. Association with environmental events.

BACKGROUND: Self-injurious behaviour is commonly seen in Cornelia de Lange syndrome (CdLS). However, there has been limited research into the aetiology of self-injury in CdLS and whether environmental factors influence the behaviour. METHODS: We observed the self-injury of 27 individuals with CdLS and 17 participants who did not have CdLS matched for age, gender, level of intellectual disability and mobility. Descriptive analyses were used to determine the extent to which environmental events were associated with self-injury. RESULTS: Lag sequential analysis of the association between self-injurious behaviour and environmental events revealed no differences between the two groups in terms of either the number or degree of environmental associations. CONCLUSIONS: The results suggest that the associations between the environment and self-injury in CdLS do not differ from those seen in the broader population of people with intellectual disability. By implication the social reinforcement hypothesis is equally applicable to both groups.

Health and sleep problems in Cornelia de Lange Syndrome: a case control study.

BACKGROUND: Self-injury, sleep problems and health problems are commonly reported in Cornelia de Lange Syndrome (CdLS) but there are no comparisons with appropriately matched participants. The relationship between these areas and comparison to a control group is warranted. METHOD: 54 individuals with CdLS were compared with 46 participants with intellectual disability (ID) of mixed aetiology who were similar in terms of degree of ID, mobility, age and gender using informant-based measures of health problems, sleep and self-injury. RESULTS: Participants with CdLS experienced significantly more current and lifetime health problems with eye problems and gastrointestinal disorders prominent. Although 55% of those with CdLS experienced sleep problems this prevalence was not different from the comparison group. Sleep disorder was not associated with self-injury in the CdLS group, skin problems were associated with severity of self-injury but not presence. DISCUSSION: People with CdLS experience a range of significant health problems and have more health concerns than others with the same degree of ID. Although this has been well documented in the past, the current high prevalence of health concerns indicates the need for regular health assessment and appropriate intervention.

The association between environmental events and self-injurious behaviour in Cornelia de Lange syndrome.

BACKGROUND: There has been limited empirical research into the environmental causes of self-injury in Cornelia de Lange syndrome. The present study examined the variability of self-injurious behaviour in Cornelia de Lange syndrome across environmental setting events. Additionally, the association between setting events and more specific environmental events was examined. METHOD: A descriptive analysis of observational data on eight children with Cornelia de Lange syndrome aged between 4 and 14 years was carried out. The association between self-injurious behaviour and four environmental setting events and between specific environmental events and setting events was examined using established statistical methods for observational data. RESULTS: Seven out of eight of the participants showed at least one form of self-injurious behaviour that was associated with a particular setting event. The study also demonstrated that the relationship between setting events and environmental events is extremely variable across individuals. CONCLUSIONS: Self-injurious behaviour in some individuals with Cornelia de Lange syndrome is associated with environmental events although the precise nature of the association warrants clarification. Using broad setting events as a methodological tool in isolation provides some insight into the role of specific environmental factors in maintaining self-injurious behaviour but the integrity of setting events must be established.