Psychopathology in young people with intellectual disability

Psychometric properties of the Dynamic Risk Outcome Scales (DROS) for individuals with mild intellectual disability or borderline intellectual functioning and externalizing behaviour problems

BACKGROUND

The present study examined the psychometric properties of the Dynamic Risk Outcome Scales (DROS), an instrument developed to measure dynamic risk factors in individuals with mild intellectual disabilities or borderline intellectual functioning (MID-BIF) and externalizing (including offending-like) behaviour problems.

METHOD

The sample consisted of 606 clients (86% male) from inpatient treatment wards at a facility for individuals with MID-BIF and externalizing behaviour problems.

RESULTS

The DROS showed an acceptable factor structure, good internal consistency, significant test-retest reliability and fair to excellent inter-rater reliabilities for most subscales and total score. Compared to the Adult Behavior Checklist (ABCL; Achenbach & Rescorla, 2003 Manual for the ASEBA adult forms and profiles. Burlington, VT: University of Vermont, Research Center for Children, Youth, & Families), the DROS showed convergent and divergent validity, concurrent and longitudinal validity.

CONCLUSIONS

The DROS is a reliable and valid instrument to measure dynamic risk factors in clients with MID-BIF. Future research on the DROS will focus on the assessment of recidivism and the inclusion of internalizing problems.

Transition to adult mental health services for young people with an intellectual disability

People with intellectual disabilities (ID) experience high rates of mental health problems, particularly during the period of transition to adulthood. It is therefore important that the transition from child- to adult-oriented health services for people with ID is well managed to ensure appropriate orientation to ongoing adult mental health care. The purpose of this paper is to summarise the impact and experience of transition to adult mental health care for people with ID and those who support them, as well as issues related to current policy and practice in this area. Several opportunities for improvement are identified in the broad areas of policy, service structure and organisation, research and workforce capacity. Enhancements in these areas will lead to improved outcomes for young people with ID transitioning from child- to adult-oriented mental health care.

Intellectual disability content within tertiary medical curriculum: how is it taught and by whom?

BACKGROUND

Individuals with intellectual disability experience higher rates of physical and mental health conditions compared with the general population, yet have inequitable access to health care services. Improving the workplace capacity of medical professionals to meet the needs of this population is one way to reduce barriers to care and improve health outcomes. Using diverse pedagogy appropriate to learning outcomes to teach medical students about intellectual disability is a necessary step in improving future workplace capacity. However, there is a lack of research into how, and by whom, medical students are taught about intellectual disability. The aim of this study was to investigate this through an audit of Australian medical school curricula.

METHODS

The Deans of Australian universities that provide accredited medical degrees (n = 20) were invited by email to participate in a two-phase audit of intellectual disability content in the curricula. Phase 1 (n = 14 schools) involved the Dean's delegate completing a telephone interview or questionnaire regarding medical course structure. If intellectual disability content was identified, a unit coordinator was invited to complete a survey regarding how this content was taught and by whom (Phase 2; n = 12 schools).

RESULTS

There was considerable variability across Australian medical schools regarding methods used to teach content about intellectual disability. Didactic teaching methods were most frequently used (62% of units included some form of lecture), but workshops and tutorials were reasonably well represented (34% of units contained one or both). Thirty-six percent of units included two or more teaching methods. Almost all schools (83%) used some problem- and/or enquiry-based learning. Educator backgrounds included medicine, nursing, and allied health. A majority of schools (n = 9, 75%) involved people with intellectual disability designing and teaching content, but the extent to which this occurred was inconsistent.

CONCLUSIONS

Renewing curricula around intellectual disability across all medical schools by introducing varied teaching methods and the inclusion of people with intellectual disability would assist students to develop knowledge, skills, attitudes, and confidence in intellectual disability health. Such renewal offers the potential to reduce barriers to service this population regularly face, thereby improving their health outcomes.

Pilot study: undetected post-traumatic stress disorder symptoms among intellectually disabled

Background: Individuals with intellectual disability respond differently to traumatic events, compared to the general population, which makes post-traumatic stress disorder (PTSD) symptoms difficult to recognize. The current study aims to examine the presence of undetected PTSD among individuals with intellectual disability and a known history of trauma exposure. Method: Nine individuals, who have not previously been diagnosed with PTSD, were evaluated for PTSD symptoms through case reports, which include descriptions of medical history, symptoms and behavior described in the former diagnostic reports, potential traumatic experiences, current symptoms and behavior in accordance to the Lancaster and North Gate Trauma Scale, and PTSD criteria from DM-ID. Results: Four out of the nine participants met the DM-ID criteria for PTSD. Conclusions: The current findings highlight the importance of including cognitive impairment and developmental level in the screening, referral and treatment process of PTSD.

An investigation of the determinants of quality of life in adolescents and young adults with Down syndrome

BACKGROUND

Young people with Down syndrome experience varying abilities in activities of daily living, cognitive functioning, behaviour and social skills. The aim of this research was to investigate, from a carer's perspective, the factors that influenced the quality of life of these young people.

METHODS

Families of young people with Down syndrome (n = 197), aged 16-31 years, living in Western Australia, took part in a questionnaire study regarding young person daily functioning, family characteristics, medical background and quality of life measured by the Kidscreen 27-item scale. Kidscreen-10 total score was used as an outcome in the investigation of determinants with higher scores indicating better quality of life.

RESULTS

After adjustment for confounders including carer's mental health measured by the Depression and Anxiety Scale (DASS), global impact of illness as well as impact of mental health and bowel conditions were all negatively associated with the young person's quality of life. Young people who had three or more friends had better quality of life than those with no friends. Scores were lower (reflecting poor quality of life) in individuals who had more behavioural problems but these relationships were attenuated after adjustment for confounders and DASS.

CONCLUSIONS

Overall, our findings revealed that quality of life of young people with Down syndrome was most negatively associated with burden of medical conditions, but also with lack of friendships. We were somewhat surprised to find the effect of medical problems on quality of life persisting into adolescence and adulthood where in general the burden of medical comorbidities is much less than in childhood.

Assessing the Confidence of Australian Mental Health Practitioners in Delivering Therapy to People With Intellectual Disability

Research supports the use of psychological therapies among people with mild to moderate intellectual disability (ID). One barrier to people with ID accessing psychological treatments is the confidence of mental health practitioners. This article explores the confidence of Australian clinicians in providing therapy to people with ID. One hundred and fifty-two psychologists and counselors in Australia completed a survey exploring self-reported confidence when working with clients who have ID and mental health difficulties. Clinicians were most confident with generic counseling skills, but less confident with elements of assessments and interventions. The use of treatment protocols was endorsed as helpful particularly among those with low confidence. This highlights the need for dissemination of treatment guides and training to help increase clinician confidence.

Early vulnerabilities for psychiatric disorders in elementary schoolchildren from four Brazilian regions

PURPOSE

The purpose of the study is to identify early vulnerabilities for psychiatric disorders among Brazilian elementary school children, controlling for familial and community adversities.

METHODS

This is a cross-sectional study examining the association between child psychiatric disorders and potential early vulnerabilities (disability, low intellectual quotient, and negative dimensions of the temperament trait self-directedness (low resourcefulness, low purposefulness, low enlightened second nature), controlling for the potential confounders: familial and community adversities.

SAMPLE

Four probabilistic samples of second-to-sixth grade students from public schools in four towns from different Brazilian regions (N = 1620). The following instruments were applied: the K-SADS-PL (to assess child/adolescent psychiatric disorders); the Ten-Question Screen (to measure child disability); three structured questions used as proxy of self-directedness; and the reduced version of the WISC-III to measure IQ. To evaluate familial/community adversities: Self-Report Questionnaire-SRQ-20 (to assess maternal/primary caretaker anxiety/depression); questions derived from structured questionnaires (to measure child abuse, marital physical violence, neighborhood violence); Brazilian Association of Research Companies questionnaire (to evaluate poverty/socioeconomic status). Trained psychologists interviewed mothers/primary caretakers and evaluated children/adolescents individually.

RESULTS

A final logistic regression model showed that children/adolescents with low resourcefulness, low purposefulness, low enlightened second nature, lower IQ and disability were more likely to present any child psychiatric disorders.

CONCLUSION

Early vulnerabilities such as low IQ, presence of disability, and dimensions of temperament were associated with psychiatric disorders among Brazilian elementary school children, after controlling for familial and ecological confounders. These early vulnerabilities should be considered in mental health prevention/intervention programs in low-middle-income countries like Brazil.

Depression and anxiety symptoms during the transition to early adulthood for people with intellectual disabilities

BACKGROUND

The transition to adulthood is a major developmental milestone; a time of self-discovery and increased independence. For young adults (YA) with intellectual disabilities (ID), however, this period is especially challenging. The increased incidence of mental health disorders in this population, such as depression and anxiety, make this transition even more difficult, increasing caregiver burden at a time when the young adult would traditionally be gaining independence. It is not clear, however, why YA with ID are more susceptible and what factors may predict mental health symptoms.

METHOD

Potential risk and protective factors (demographic variables, coping styles, sense of hopelessness, unmet achievement of adulthood milestones, self-reflection and insight) of anxiety and depression symptoms were assessed in 55 YA with ID and a sample of age-matched controls.

RESULTS

Insight was the strongest predictor of anxiety (with gender in the controls) for YA with and without ID, with increased insight predicting fewer anxiety symptoms. However, YA with ID had significantly less insight than their aged-matched counterparts and significantly higher levels of anxiety. They were also less likely to have achieved traditional adulthood milestones. Maladaptive coping was the strongest predictor of depression for YA with ID. In comparison, both maladaptive coping and insight predicted depression in controls. More maladaptive coping predicted increased depressive symptoms in both populations, whilst increased insight predicted fewer depressive symptoms in controls.

CONCLUSIONS

Insight and maladaptive coping are potential targets in the treatment of anxiety and depression among YA with ID. Longitudinal intervention studies exploring the efficacy of such targeted programmes in reducing mental health symptoms and improving the transition to adulthood for these young people are recommended.

Autistic, Aberrant, and Food-Related Behaviors in Adolescents and Young Adults with Prader-Willi Syndrome: The Effects of Age and Genotype

The effects of age and genotype were examined, with regard to the severity of aberrant, autistic, and food-related behaviors in Prader-Willi syndrome (PWS), with an emphasis on the contrast between adolescents and young adults. The Aberrant Behavior Checklist Japanese version (ABC-J), the Food Related Problem Questionnaire (FRPQ), and the Pervasive Developmental Disorders Autism Society Japan Rating Scale (PARS) were administered to 65 PWS patients, including 20 adolescents (ages 12 to 17) and 45 young adults (ages 18 to 29). Significant differences (Mann-Whitney U tests) were found in ABC-J (p = 0.004) and PARS (p = 0.021), with lower scores in adolescents than in young adults. While DEL subgroups showed no significant differences between the two age groups in ABC-J (p = 0.063) and PARS (p = 0.134), mUPD subgroups showed a statistically significant difference in terms of ABC-J (p = 0.007). No significant differences were found between adolescents and young adults, in terms of FRPQ (p = 0.163). These results suggest that aberrant and autistic behaviors follow a marked worsening trend from around the age of 18. On the other hand, food-related behaviors give no sign of change at this transitory stage. Young adults with mUPD were found to be significantly more severe than adolescents with mUPD, in terms of aberrant behaviors.

Concurrence of the strengths and difficulties questionnaire and developmental behaviour checklist among children with an intellectual disability

BACKGROUND

The Strengths and Difficulties Questionnaire (SDQ) is widely used to measure emotional and behavioural problems in typically developing young people, although there is some evidence that it may also be suitable for children with intellectual disability (ID). The Developmental Behaviour Checklist - Parent version (DBC-P) is a measure of emotional and behavioural problems that was specifically designed for children and adolescents with an ID. The DBC-P cut-off has high agreement with clinical diagnosis. The aim of this study was to estimate the relationship between DBC-P and SDQ scores in a sample of children with ID.

METHOD

Parents of 83 young people with ID aged 4-17 years completed the parent versions of the SDQ and the DBC-P. We evaluated the concurrent validity of the SDQ and DBC-P total scores, and the agreement between the DBC-P cut-off and the SDQ cut-offs for 'borderline' and 'abnormal' behaviour.

RESULTS

The SDQ total difficulties score correlated well with the DBC-P total behaviour problem score. Agreement between the SDQ borderline cut-off and the DBC-P cut-off for abnormality was high (83%), but was lower for the SDQ abnormal cut-off (75%). Positive agreement between the DBC-P and the SDQ borderline cut-off was also high, with the SDQ borderline cut-off identifying 86% of those who met the DBC-P criterion. Negative agreement was weaker, with the SDQ borderline cut-off identifying only 79% of the participants who did not meet the DBC-P cut-off.

CONCLUSION

The SDQ borderline cut-off has some validity as a measure of overall levels of behavioural and emotional problems in young people with ID, and may be useful in epidemiological studies that include participants with and without ID. However, where it is important to focus on behavioural profiles in children with ID, a specialised ID instrument with established psychometric properties, such as the DBC-P, may provide more reliable and valid information.

Thailand's national universal developmental screening programme for young children: action research for improved follow-up

Introduction

In low-income and middle-income countries, it is estimated that one in every three preschool-age children are failing to meet cognitive or socioemotional developmental milestones. Thailand has implemented a universal national developmental screening programme (DSPM) for young children to enable detection of developmental disorders and early intervention that can improve child health outcomes. DSPM implementation is being hampered by low attendance at follow-up appointments when children fail the initial screening.

Methods

Action research, using qualitative methods was conducted with 19 caregivers, 5 health workers and 1 chief at two Health Promotion Hospitals to explore the factors affecting attendance at follow-up appointments. Transcripts and notes were analysed using descriptive content analysis. Findings were then discussed with 48 health workers, managers, researchers and policymakers.

Results

The high workload of health workers during busy vaccination clinics, and inadequate materials prevented clear communication with caregivers about the screening, how to stimulate child development and the screening result. Caregivers, particularly grandparents, had a lack of understanding about how to stimulate child development, and did not fully understand failed screening results. Caregivers felt blamed for not stimulating their child’s development, and were either worried that their child was severely disabled, or they did not believe the screening result and therefore questioned its usefulness. This led to a lack of attendance at follow-up appointments.

Conclusion

Task-sharing, mobile health (mhealth), community outreach and targeted interventions for grandparent caregivers might increase awareness about child development and screening, and allow health workers more time to communicate effectively. Sharing best practices, communication training and mentoring of DSPM workers coupled with mhealth job aids could also improve caregiver attendance at follow-up. Engagement of caregivers in understanding the barriers to attendance at follow-up and engagement of stakeholders in the design and implementation of interventions is important to ensure their effectiveness.

Gene networks associated with non-syndromic intellectual disability

Non-syndromic intellectual disability (NS-ID) is a genetically heterogeneous disorder, with more than 200 candidate genes to date. Despite the increasing number of novel mutations detected, a relatively low number of recurrently mutated genes have been identified, highlighting the complex genetic architecture of the disorder. A systematic search of PubMed and Medline identified 245 genes harbouring non-synonymous variants, insertions or deletions, which were identified as candidate NS-ID genes from case reports or from linkage or pedigree analyses. From this list, 33 genes are common to syndromic intellectual disability (S-ID) and 58 genes are common to certain neurological and neuropsychiatric disorders that often include intellectual disability as a clinical feature. We examined the evolutionary constraint and brain expression of these gene sets, and we performed gene network and protein-protein interaction analyses using GeneGO MetaCore^TM and DAPPLE, respectively. The 245 NS-ID candidate genes were over-represented in axon guidance, synaptogenesis, cell adhesion and neurotransmission pathways, all of which are key neurodevelopmental processes for the establishment of mature neuronal circuitry in the brain. These 245 genes exhibit significantly elevated expression in human brain and are evolutionarily constrained, consistent with expectations for a brain disorder such as NS-ID that is associated with reduced fecundity. In addition, we report enrichment of dopaminergic and glutamatergic pathways for those candidate NS-ID genes that are common to S-ID and/or neurological and neuropsychiatric disorders that exhibit intellectual disability. Collectively, this study provides an overview and analysis of gene networks associated with NS-ID and suggests modulation of neurotransmission, particularly dopaminergic and glutamatergic systems as key contributors to synaptic dysfunction in NS-ID.

Psychopathology of adolescents with an intellectual disability who present to general hospital services

OBJECTIVE

Adolescents with intellectual disability have increased rates of psychopathology compared with their typically developing peers and present to hospital more frequently for ambulant conditions. The aim of this study is to describe the psychopathology and related characteristics of a sample of adolescents with intellectual disability who presented to general hospital services.

METHOD

We investigated a cohort of adolescents with intellectual disability in South East Queensland, Australia between January 2006 and June 2010. Demographic and clinical data were obtained via mailed questionnaires and from general practice notes. Psychopathology was measured with the Short Form of the Developmental Behaviour Checklist.

RESULTS

Of 98 individuals presenting to hospital, 71 (72.5%) had significant levels of psychopathology. Unknown aetiology for the intellectual disability was associated with presence of problem behaviours. Adolescents with more severe intellectual disability were more likely to have major problem behaviours. Co-morbid physical health issues were not associated with psychopathology. Only 12 (12.1%) adolescents had undergone specialized mental health intervention.

CONCLUSIONS

The general hospital environment may offer opportunities for liaison psychiatry services to screen and provide management expertise for adolescent individuals with intellectual disability presenting for physical health issues.

Syndrome specific modules to enhance the Stepping Stones Triple P public health intervention

BACKGROUND

Service responses to behaviour phenotypes include care by expert clinicians, syndrome-specific clinics, disability-specific mental health services and generic mental health services. While these services contribute to care, they are often of limited accessibility.

METHODS

We describe a population-wide public health intervention aimed at increasing the accessibility of services to the target population. Stepping Stones Triple P (SSTP) is a public health intervention of known efficacy in reducing behaviour problems when delivered to parents of children aged 0-12 with mixed developmental disabilities.

RESULTS

The strategy we discuss involves enhancing SSTP with modules for specific causes of developmental disabilities including Down, Fetal Alcohol, Fragile X, Prader-Willi and Williams syndromes.

CONCLUSIONS

We propose that enhancing SSTP with syndrome specific modules will increase the accessibility of support to families who have a child with a specific behaviour phenotype. We suggest that future research should confirm the public health impact of the modified SSTP programme using the RE-AIM framework.

Age and gender-related differences in emotional and behavioural problems and autistic features in children and adolescents with Down syndrome: a survey-based study of 674 individuals

BACKGROUND

Recent studies have indicated an increased risk of autism, behavioural and emotional problems and attention-deficit/hyperactivity disorder in individuals with Down syndrome.

METHOD

In a large-scale survey-based study, we examined the rates of these problems and their relationship to age and gender, in a sample of 674 individuals (4-18 years) with Down syndrome. The relationship with IQ level was also explored in a subsample (n = 175). The Strengths and Difficulties Questionnaire and the Social Communication Questionnaire were used to assess behavioural and emotional problems and autism traits.

RESULTS

On the Strengths and Difficulties Questionnaire, peer problems were the most frequently reported difficulty (48% > cut-off), followed by hyperactivity/inattention (34% > cut-off). On the Social Communication Questionnaire, 37% scored at or above cut-off (≥15) for autism spectrum disorder; 17% were at or above the suggested cut-off (≥22) for autism. Little association between age and behavioural or emotional problems or with severity of autistic symptomatology was found. However, peer problems were more common in adolescents than in junior school children (P < 0.001); Hyperactivity/inattention was less prevalent among adolescents (P < 0.001).

CONCLUSIONS

High rates of autistic features, emotional and behavioural problems are documented. These problems are related to age, gender and degree of intellectual disability.

Child’s Challenging Behaviour Scale, Version 2 (CCBS–2): Psychometric Evaluation With Young Children

OBJECTIVE. In this article, we evaluate psychometric properties of the Child’s Challenging Behaviour Scale, Version 2 (CCBS–2) with mothers of young, typically developing children.

METHOD. A cross-sectional mail survey with Australian mothers (N = 337) included the CCBS–2, the Depression Anxiety Stress Scales, and the Parents’ Evaluation of Developmental Status scale.

RESULTS. Internal consistency was good, and no gender differences in CCBS–2 scores were significant. Significant results included differences between CCBS–2 scores: among children grouped according to age, among children grouped according to pre– and post–school entry, among mothers grouped according to extent of any symptom type, and between this sample and a previously collected age-matched sample of children with disabilities.

CONCLUSION. Of the properties tested, results support sound psychometrics. The CCBS–2 can be used to differentiate children according to age, school entry, and disability as well as to identify families for potential services in behavior management and mental health.

Priority service needs and receipt across the lifespan for individuals with autism spectrum disorder

Individuals with Autism Spectrum Disorder (ASD) have a range of health, community, and social support needs across the lifespan that create age‐specific challenges in navigating service sectors. In this study, we set out to identify the priority needs of individuals with ASD across the lifespan, and the factors that predict receiving priority services. Participants included 3,317 individuals with ASD from a Canada‐wide online caregiver survey, stratified into five age groups (preschool, elementary school age, adolescence, emerging adulthood, adulthood). Priority receipt was calculated as a ratio of current services that corresponded to individualized priority need. Age‐stratified Poisson regression analyses were used to identify the sociodemographic, clinical and systemic predictors of priority receipt. Results indicate that the distribution of priority need varied by age, except for social skills programming, which was a high across all groups. The number of high and moderate priority needs diversified with age. Overall, 30% of individuals had none of their priority needs met and priority receipt decreased with age. Systemic factors were most consistently related to priority receipt across the lifespan. Understanding patterns and correlates of priority needs and use that currently exist in different age groups can inform policies to improve service access. Autism Res2017, 10: 1436–1447. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

The Familial Co-Aggregation of Attention-Deficit/Hyperactivity Disorder and Intellectual Disability: A Register-Based Family Study

OBJECTIVE

Although many studies document an association between attention-deficit/hyperactivity disorder (ADHD) and intellectual disability (ID), little is known about the etiology of this comorbidity and how it should be addressed in clinical settings. We sought to clarify this issue.

METHOD

All individuals born in Sweden between 1987 and 2006 (n = 2,049,587) were identified using the Medical Birth Register (MBR). From this we selected 7 cohorts of relatives: 1,899,654 parent-offspring pairs, 4,180 monozygotic twin pairs, 12,655 dizygotic twin pairs, 914,848 full sibling pairs, 136,962 maternal half-sibling pairs, 134,502 paternal half-sibling pairs, and 2,790,164 full cousin pairs. We used within-individual and within-family analyses to assess the association between ADHD and ID.

RESULTS

Individuals with ID were at increased risk for ADHD compared to those without ID, and relatives of participants with ID were at increased risk of ADHD compared with relatives of those without ID. The magnitude of this association was positively associated with the fraction of the genome shared by the relative pair and was lower for severe compared with mild and moderate ID. Model-fitting analyses demonstrated that 91% of the correlation between the liabilities of ADHD and ID was attributable to genetic factors.

CONCLUSION

These data provide evidence that nearly all of the comorbidity between ADHD and ID can be attributed to genetic factors, which has implications for diagnostic practice.

Intellectual disability health content within nursing curriculum: An audit of what our future nurses are taught

BACKGROUND

Individuals with intellectual disability experience chronic and complex health issues, but face considerable barriers to healthcare. One such barrier is inadequate education of healthcare professionals.

OBJECTIVE

To establish the quantity and nature of intellectual disability content offered within Australian nursing degree curricula.

DESIGN

A two-phase national audit of nursing curriculum content was conducted using an interview and online survey.

SETTING

Australian nursing schools offering pre-registration courses.

PARTICIPANTS

Pre-registration course coordinators from 31 universities completed the Phase 1 interview on course structure. Unit coordinators and teaching staff from 15 universities in which intellectual disability content was identified completed the Phase 2 online survey.

METHODS

Quantity of compulsory and elective intellectual disability content offered (units and teaching time) and the nature of the content (broad categories, specific topics, and inclusive teaching) were audited using an online survey.

RESULTS

Over half (52%) of the schools offered no intellectual disability content. For units of study that contained some auditable intellectual disability content, the area was taught on average for 3.6h per unit of study. Units were evenly distributed across the three years of study. Just three participating schools offered 50% of all units audited. Clinical assessment skills, and ethics and legal issues were most frequently taught, while human rights issues and preventative health were poorly represented. Only one nursing school involved a person with intellectual disability in content development or delivery.

CONCLUSION

Despite significant unmet health needs of people with intellectual disability, there is considerable variability in the teaching of key intellectual disability content, with many gaps evident. Equipping nursing students with skills in this area is vital to building workforce capacity.

A cross-syndrome evaluation of a new attention rating scale: The Scale of Attention in Intellectual Disability

Whilst neuropsychological research has enhanced our understanding of inattentive and hyperactive behaviours among children with intellectual disability (ID), the absence of rating scales developed for this group continues to be a gap in knowledge. This study examined these behaviours in 176 children with autism spectrum disorder (ASD), Down Syndrome (DS), or idiopathic ID using a newly developed teacher rating scale, the Scale of Attention in Intellectual Disability. Findings suggested that children with ASD had a significantly greater breadth of hyperactive/impulsive behaviours than those with DS or idiopathic ID. These findings support existing research suggesting differing profiles of attention and activity across groups. Understanding disorder-specific profiles has implications for developing strategies to support students with ID in the classroom.

What Effect Does Transition Have on Health and Well-Being in Young People with Intellectual Disabilities? A Systematic Review

BACKGROUND

Transition to adulthood might be a risk period for poor health in people with intellectual disabilities. However, the present authors could find no synthesis of evidence on health and well-being outcomes during transition in this population. This review aimed to answer this question.

METHOD

PRISMA/MOOSE guidelines were followed. Search terms were defined, electronic searches of six databases were conducted, reference lists and key journals were reviewed, and grey literature was searched. Papers were selected based on clear inclusion criteria. Data were extracted from the selected papers, and their quality was systematically reviewed. The review was prospectively registered on PROSPERO: CRD42015016905.

RESULTS

A total of 15 985 articles were extracted; of these, 17 met the inclusion criteria. The results of these articles were mixed but suggested the presence of some health and well-being issues in this population during transition to adulthood, including obesity and sexual health issues.

CONCLUSION

This review reveals a gap in the literature on transition and health and points to the need for future work in this area.

Young People with Intellectual Disability Transitioning to Adulthood: Do Behaviour Trajectories Differ in Those with and without Down Syndrome?

Background

Young people with intellectual disability exhibit substantial and persistent problem behaviours compared with their non-disabled peers. The aim of this study was to compare changes in emotional and behavioural problems for young people with intellectual disability with and without Down syndrome as they transition into adulthood in two different Australian cohorts.

Methods

Emotional and behavioural problems were measured over three time points using the Developmental Behaviour Checklist (DBC) for those with Down syndrome (n = 323 at wave one) and compared to those with intellectual disability of another cause (n = 466 at wave one). Outcome scores were modelled using random effects regression as linear functions of age, Down syndrome status, ability to speak and gender.

Results

DBC scores of those with Down syndrome were lower than those of people without Down syndrome indicating fewer behavioural problems on all scales except communication disturbance. For both groups disruptive, communication disturbance, anxiety and self-absorbed DBC subscales all declined on average over time. There were two important differences between changes in behaviours for these two cohorts. Depressive symptoms did not significantly decline for those with Down syndrome compared to those without Down syndrome. The trajectory of the social relating behaviours subscale differed between these two cohorts, where those with Down syndrome remained relatively steady and, for those with intellectual disability from another cause, the behaviours increased over time.

Conclusions

These results have implications for needed supports and opportunities for engagement in society to buffer against these emotional and behavioural challenges.

Child Adjustment and Parent Efficacy Scale-Developmental Disability (CAPES-DD): First psychometric evaluation of a new child and parenting assessment tool for children with a developmental disability

This study examined the psychometric properties of the Child Adjustment and Parent Efficacy Scale-Developmental Disability (CAPES-DD), a brief inventory for assessing emotional and behavioral problems of children with developmental disabilities aged 2- to 16-years, as well as caregivers' self-efficacy in managing these problems. A sample of 636 parents participated in the study. Children's ages ranged from 2 to 15. Exploratory and confirmatory factor analyses supported a 21-item, three-factor model of CAPES-DD child adjustment with 13 items describing behavioral (10 items) and emotional (3 items) problems and 8 items describing prosocial behavior. Three additional items were included due to their clinical usefulness and contributed to a Total Problem Score. Factor analyses also supported a 16-item, one factor model of CAPES-DD self-efficacy. Psychometric evaluation of the CAPES-DD revealed scales had satisfactory to very good internal consistency, as well as very good convergent and predictive validity. The instrument is to be in the public domain and free for practitioners and researchers to use. Potential uses of the measure and implications for future validation studies are discussed.

Psychosocial correlates of psychiatric diagnoses and maladaptive behaviour in youth with severe developmental disability

BACKGROUND

We know little about the correlates of mental health problems in youth with severe and profound intellectual disability (ID), as most research includes these youth within larger samples that include greater proportions of mild and moderate disability. The purpose of the current study was to identify the child, family and psychosocial characteristics that were associated with the presence of psychiatric diagnoses and maladaptive behaviour in youth with severe ID.

METHODS

Participants were 141 parents of youth with severe or profound levels of ID, 4 to 18 years of age. The mean age of children was 11.04 years (SD = 3.38), with 68% male and 39% with autism spectrum disorder (ASD). Parents completed a primarily online survey of child and family characteristics, negative life events, family quality of life and their own mental health.

RESULTS

Logistic regression analyses revealed that youth with a psychiatric diagnosis had higher levels of adaptive behaviour and experienced more negative life events than youth without psychiatric diagnosis, while the presence of clinically significant maladaptive behaviour was related to higher levels of adaptive behaviour, parents' mental health problems and lower family quality of life. Child age, gender, ASD status and financial hardship were not related to either outcome variable.

CONCLUSIONS

Youth with severe and profound ID who experience psychosocial stressors are more likely reported to have mental health problems than youth without such stressors. It is likely that a combination of child and family based interventions, along with with policies that address larger systemic issues of social adversity, are needed to promote mental health and treat psychopathology when it arises.

Using 'candidacy' as a framework for understanding access to mainstream psychological treatment for people with intellectual disabilities and common mental health problems within the English Improving Access to Psychological Therapies service

BACKGROUND

The Improving Access to Psychological Therapies (IAPT) service was established to address common mental health problems among the English population in a timely manner in order to counter the social and economic disadvantage accompanying such difficulties. Using the concept of candidacy, we examined how the legitimacy of claims by people with intellectual disabilities to use this service is facilitated or impeded.

METHOD

We used a sequential mixed methods design. We completed 21 interviews with a range of stakeholders, including people with intellectual disabilities and their carers. Themes from the interviews were used to design an online survey questionnaire that was returned by 452 staff from IAPT and specialist intellectual disability services.

RESULTS

Using the candidacy framework, we noted that eligibility and access to IAPT were achieved through dynamic and iterative processes of negotiation involving people with intellectual disabilities and their supporters on one side and IAPT staff and service structures on the other. Barriers and facilitators were apparent throughout the seven dimensions of candidacy (identification, navigation, permeability of services, appearances, adjudications, offers and resistance and operating conditions) and were linked to discourses relating to the character and purpose of IAPT and specialist intellectual disability services.

CONCLUSIONS

Opportunities exist for some people with intellectual disabilities to assert their candidacy for IAPT input, although there are barriers at individual, professional, organisational and structural levels. More attention needs to be paid to how principles of inclusiveness are operationalised within IAPT teams and to the mental health facilitation role of specialist intellectual disability staff.

Intellectual disability health content within medical curriculum: an audit of what our future doctors are taught

BACKGROUND

There is a high burden of unmet health needs for people with intellectual disability. Despite experiencing significantly higher rates of morbidity and mortality compared with the general population, this group faces greater barriers to accessing healthcare. While increasing workplace capacity is one way to reduce this inequitable access, previous research indicates a scarcity of undergraduate teaching in intellectual disability. The aim of the study was to determine the extent and nature of intellectual disability content currently offered within medical degree curricula.

METHODS

All Australian universities (n = 20) providing accredited medical training were invited to participate in a two-phase audit via an email invitation to the Dean of each medical school. The Dean's delegate from 14 medical schools completed Phase 1, which involved a questionnaire or telephone interview about the overall medical course structure. Unit coordinators and/or teaching staff from 12 medical schools completed Phase 2, which involved an online survey about intellectual disability content within the curriculum.

RESULTS

In Australia, medical school curricula contain a median of 2.55 h of compulsory intellectual disability content. The majority of universities only offer a small amount of compulsory content. Of compulsory units, intellectual disability teaching is minimal in sexual health and emergency medicine (only one unit offered in one school for each). Topics of key relevance in intellectual disability health such as human rights issues, interdisciplinary team work and preventative health are poorly represented in intellectual disability teaching. Elective content varies markedly across universities (1 to 122 h), but emergency medicine, women's health, men's health and many other specialist medicine areas are not represented. Inclusive practice is inconsistent in degree and nature, but a majority of universities (nine) involve people with intellectual disability in the development or delivery of content.

CONCLUSIONS

There is a mismatch between the considerable unmet health needs of people with intellectual disability and the inconsistent teaching within medical schools. Future doctors will be better equipped to support the health and wellbeing of people with intellectual disability if curricula are enhanced in this area.

The co-occurrence of mental disorders in children and adolescents with intellectual disability/intellectual developmental disorder

PURPOSE OF REVIEW

The study summarizes supportive epidemiological data regarding the true co-occurrence (comorbidity) and course of mental disorders in children with intellectual disability/intellectual developmental disorders (ID/IDD) across the lifespan.

RECENT FINDINGS

Published studies involving representative populations of children and adolescents with ID/IDD have demonstrated a three to four-fold increase in prevalence of co-occurring mental disorders. The effect of age, sex, and severity (mild, moderate, severe, and profound) and socioeconomic status on prevalence is currently not clearly understood. To date there are no prevalence estimates of co-occurring mental disorders in youth identified using the new DSM-5 (and proposed ICD-11) definition of ID/IDD using measures of intellectual functions and deficits in adaptive functioning with various severity levels defined on the basis of adaptive functioning, and not intellectual quotient scores.

SUMMARY

The true relationship between two forms of morbidity remains complex and causal relationships that may be true for one disorder may not apply to another. The new conceptualization of ID/IDD offers a developmentally better informed psychobiological approach that can help distinguish co-occurrence of mental disorders within the neurodevelopmental section with onset during the developmental period as well as the later onset of other mental disorders.

The Developmental Trajectory of Self-Injurious Behaviours in Individuals with Prader Willi Syndrome, Autism Spectrum Disorder and Intellectual Disability

In the present study we examined the nature and developmental trajectory of self-injurious behaviour in Prader Willi syndrome (PWS) and autism spectrum disorder (ASD). The development of interventions is greatly aided by understanding gene to behaviour pathways, and this requires an accurate description of the behaviour phenotype, that is, which types and natural history of self-injurious behaviour are more common in PWS and ASD and which are shared with other forms of developmental disability. Self-injury displayed by individuals with PWS and individuals with ASD was compared with that reported in a group of individuals with intellectual disability due to mixed aetiology (ID group). Three self-injurious behaviours (head banging, skin-picking and hitting and/or biting self) were measured on five occasions over 18 years using the Developmental Behaviour Checklist (DBC) a well-validated caregiver report measure. Rates of skin picking were higher in individuals with PWS and hitting and/or biting self was higher in individuals with ASD compared to the ID group. Rates of head banging were similar across the three groups. Over time, skin-picking and head banging increased with age for individuals with ASD and hitting and/or biting self increased for the PWS group. In the PWS and mixed ID groups head banging decreased with age. These findings suggest that the typology and developmental trajectories of self-injurious behaviours differ between those with PWS and ASD.

Contextual Factors Predict Patterns of Change in Functioning over 10 Years Among Adolescents and Adults with Autism Spectrum Disorders

In the present study, we jointly employ and integrate variable- and person-centered approaches to identify groups of individuals with autism spectrum disorders (ASD) who have similar profiles of change over a period of 10 years across three critical domains of functioning: maladaptive behaviors, autism symptoms, and daily living skills. Two distinct developmental profiles were identified. Above and beyond demographic and individual characteristics, aspects of both the educational context (level of inclusion) and the family context (maternal positivity) were found to predict the likelihood of following a positive pattern of change. Implementing evidence-based interventions that target the school and home environments during childhood and adolescence may have lasting impacts on functioning into adulthood for individuals with ASD.

Mental health needs and availability of mental health care for children and adolescents with intellectual disability in Berlin

BACKGROUND

The increased risk of mental health problems in children and adolescents with intellectual disability (ID) has been reported in several studies. However, almost no research has been conducted on parents' experiences with the general mental health system. We have investigated the prevalence of emotional and behavioural problems in children with ID as well as the availability and quality of mental health care from the parents' point of view.

METHODS

Teachers of specialised schools for ID in Berlin were asked to complete the Teacher's Report Form (TRF) of the Child Behavior Checklist. Information was collected for 1226 children and adolescents aged 6-18 years with mild to profound ID (response 70.5%). The availability and quality of mental health care was assessed by a questionnaire given to parents who had already been seeking help for their children. A total of 330 parents completed the questionnaires (response 62.0%). In addition to univariate analysis, we conducted multiple logistic regressions regarding the psychopathology reported by teachers (TRF-syndrome scales) and difficulties concerning mental health care reported by parents for a paired sample of 308 children.

RESULTS

Overall, 52.4% of the children and adolescents with ID had a total problem score on the TRF in the deviant range (47.1% when eliminating four items reflecting cognitive deficits). Compared with the general population normative sample of children, this is a three-time higher prevalence. The most striking problems were thought problems (schizoid and obsessive-compulsive), aggressive behaviour, attention problems and social problems. Parents whose children had more severe behavioural or emotional dysfunction reported more difficulties with the mental health system. From the parents' point of view, mental health professionals frequently did not feel responsible or were not sufficiently skilled for the treatment of children with ID. As a consequence, 96% of all parents were longing for specialised in- and outpatient services.

CONCLUSIONS

This study confirms the findings from other studies regarding the high rate of co-occurrence of ID and mental health problems in youths. Results indicate that both are strongly requested by parents: specialised in- and outpatient services, as well as more professional general services and equitable treatment for all children, with and without ID.

Informant agreement for youth with autism spectrum disorder or intellectual disability: a meta-analysis

This study investigated informant agreement on emotional and behavior problems and social skills in youth with autism spectrum disorder or intellectual disability using meta-analytic methods. Forty-nine studies were included, consisting of 107 effect sizes. The mean weighted effect size across all raters and all behaviors was .36, reflecting moderate agreement. Consistent with meta-analyses in typically developing youth, pairs of similar informants (e.g., parent-parent) demonstrated higher agreement compared to pairs of different raters (e.g., parent-teacher). With all rater pairs combined, agreement was significantly higher for externalizing problems (r = .42) than either internalizing problems (r = .35) or social skills (r = .30). Several factors appear to moderate the level of agreement among informants, including the youth's diagnosis, age, and IQ.

Association between adaptive behaviour and age in adults with Down syndrome without dementia: examining the range and severity of adaptive behaviour problems

BACKGROUND

Studies on adaptive behaviour and ageing in adults with Down syndrome (DS) (without dementia) have typically analysed age-related change in terms of the total item scores on questionnaires. This research extends the literature by investigating whether the age-related changes in adaptive abilities could be differentially attributed to changes in the number or severity (intensity) of behavioural questionnaire items endorsed.

METHODS

The Adaptive Behaviour Assessment System-II Adult (ABAS-II Adult) was completed by parents and caregivers of 53 adults with DS aged between 16 and 56 years. Twenty adults with DS and their parents/caregivers were a part of a longitudinal study, which provided two time points of data. In addition 33 adults with DS and their parents/caregivers from a cross-sectional study were included. Random effects regression analyses were used to examine the patterns in item scores associated with ageing.

RESULTS

Increasing age was found to be significantly associated with lower adaptive behaviour abilities for all the adaptive behaviour composite scores, expect for the practical composite. These associations were entirely related to fewer ABAS-II Adult items being selected as present for the older participants, as opposed to the scores being attributable to lower item severity.

CONCLUSIONS

This study provides evidence for a differential pattern of age-related change for various adaptive behaviour skills in terms of range, but not severity. Possible reasons for this pattern will be discussed. Overall, these findings suggest that adults with DS may benefit from additional support in terms of their social and conceptual abilities as they age.

Supporting primary healthcare professionals to care for people with intellectual disability: a research agenda

BACKGROUND

The vast health inequities experienced by people with intellectual disability remain indisputable. Persistent and contemporary challenges exist for primary healthcare providers and researchers working to contribute to improvements to the health and well-being of people with intellectual disability. Over two decades after the only review of supports for primary healthcare providers was published, this paper contributes to an evolving research agenda that aims to make meaningful gains in health-related outcomes for this group.

METHODS

The present authors updated the existing review by searching the international literature for developments and evaluations of multinational models of care.

RESULTS

Based on our review, we present three strategies to support primary healthcare providers: (i) effectively using what we know, (ii) considering other strategies that offer support to primary healthcare professionals and (iii) researching primary health care at the system level.

CONCLUSIONS

Strengthening primary care by supporting equitable provision of health-related care for people with intellectual disability is a much needed step towards improving health outcomes among people with intellectual disability. More descriptive quantitative and qualitative research, as well as intervention-based research underpinned by rigorous mixed-methods evaluating these strategies at the primary care level, which is sensitive to the needs of people with intellectual disability will assist primary care providers to provide better care and achieve better health outcomes.

ACCESSIBLE ABSTRACT

Many people with intellectual disability have poor health. The authors reviewed what has been written by other researchers about how to improve the health of people with intellectual disability. In the future, people who support adults with intellectual disability should continue doing what they do well, think of other ways to improve health, and do more research about health. At all times, the needs of people with intellectual disability should be the greatest concern for those trying to support them.

Association of physical activity and health status with intelligence quotient of high school students in Jeddah

[Purpose] The present study investigated the relationships of physical activity and healthiness with the intelligence quotients of high school students in Jeddah. [Subjects and Methods] A total of 135 male and female students were randomly drawn from public and private secondary schools in Jeddah. A self-designed questionnaire was distributed to the students that included demographic, physical activity, and health status sections. Body mass index measurement and an intelligence quotient test were carried out for all students. In addition, samples of blood were collected to estimate hemoglobin and serum iron. [Results] The highest proportions of males and females (39.1% and 51% respectively) had an intelligence quotient score of more than 75%. Moreover, the findings revealed that about 35% of the students were categorized as overweight obesity, and there was aninverse correlation between body mass index and physical activity. Students who shared physical education classes and exercising at and outside school showed a positive correlation with high IQ scores. Regarding hemoglobin and iron levels, there were significant correlations between their levels in blood and IQ. [Conclusion] The intelligence quotient of adolescent students is positively associated with physical activity and health status.

The developmental trajectory of disruptive behavior in Down syndrome, fragile X syndrome, Prader-Willi syndrome and Williams syndrome

The aim of this study was to investigate the developmental trajectories of verbal aggression, physical aggression, and temper tantrums in four genetic syndrome groups. Participants were part of the Australian Child to Adult Development Study (ACAD), which collected information from a cohort of individuals with an intellectual disability at five time points over 18 years. Data were examined from a total of 248 people with one of the four following syndromes: Down syndrome, Fragile X syndrome, Prader-Willi syndrome, or Williams syndrome. Changes in behaviors were measured using validated items from the Developmental Behavior Checklist (DBC). The results indicate that, while verbal aggression shows no evidence of diminishing with age, physical aggression, and temper tantrums decline with age before 19 years for people with Down syndrome, Fragile X syndrome, and William syndrome; and after 19 years for people with Prader-Willi syndrome. These findings offer a somewhat more optimistic outlook for people with an intellectual disability than has previously been suggested. Research is needed to investigate the mechanisms predisposing people with PWS to persistence of temper tantrums and physical aggression into adulthood.

Patterns of depressive symptoms and social relating behaviors differ over time from other behavioral domains for young people with Down syndrome

People with intellectual disabilities are at a higher risk for experiencing behavioral, emotional, and psychiatric problems in comparison with the general population. People with Down syndrome have been reported as experiencing fewer behavioral problems than others with intellectual disability, although still at a greater level than the non-intellectually disabled population, except for depression and Alzheimer disease. The aim of this study was to describe the trajectories of subscales of behavior, including depressive symptoms, communication disturbance, anxiety, disruptiveness, and social relating abilities, for young adults with Down syndrome.Families of young adults with Down syndrome living in Perth, Western Australia, participated in a questionnaire study over 8 years, 2004 (n = 255), 2009 (n = 191), and 2011 (n = 188). Questionnaires collected information about young person characteristics and family functioning. The parent-completed Developmental Behavior Checklist-Adult (DBC-A) and Developmental Behavior Checklist-Primary Carer Version (DBC-P) were used to measure emotional and behavioral problems. These measures include the following subscales: disruptive, communication and anxiety disturbances, self-absorbed, antisocial, depressive, and social relating.DBC score declined from 2004 to 2011 reflecting an improvement in behavior in the self-absorbed (coeff -0.011, 95% confidence interval (CI) -0.031, -0.008), anxiety (coef -0.009 95%CI -0.129, -0.006), communication disturbances (coeff -0.008, 95% CI -0.012, -0.005) and disruptive/antisocial behavior (coeff -0.013, 95% CI -0.016, -0.009) subscales. Subscales for depressive symptoms and social relating problems decreased less (coeff -0.003, 95% CI -0.007, -0.0001) (coeff -0.003 95% CI -0.007, 0.001). Young people who were lower functioning were reported as exhibiting significantly more behavioral problems across every subscale when compared with those who were higher functioning.Behavior of young adults with Down syndrome improves over time but depressive symptoms and social relating behavior problems persist into adulthood. It is possible that those with persistent depressive symptoms are at a high risk for developing depressive illness in adulthood. Identifying young people with Down syndrome who are at risk for developing depression in adult life has implications for prevention and early treatment.

Development of a New Attention Rating Scale for Children With Intellectual Disability: The Scale of Attention in Intellectual Disability (SAID)

Difficulties with attention, impulsivity, and hyperactivity are thought to be as common among children with intellectual disability (ID) as they are in children without ID. Despite this, there is a lack of scales to specifically assess ADHD symptomatology in children and adolescents with ID. This article describes the development and evaluation of a teacher-completed measure; the Scale of Attention in Intellectual Disability (SAID). A community survey of 176 teachers of children 5-13 years of age, with ID at all levels of impairment indicated that the T-SAID is a reliable and valid measure. Integrating this scale with neuropsychological and clinical research holds exciting promise for enhancing our understanding of the nature of attention difficulties within populations with ID.

Cognitive training as a resolution for early executive function difficulties in children with intellectual disabilities

Core executive functions (EF) such as attention, and working memory have been strongly associated with academic achievement, language development and behavioral stability. In the case of children who are vulnerable to cognitive and learning problems because of an underlying intellectual disability, EF difficulties will likely exacerbate an already compromised cognitive system. The current review examines cognitive training programs that aim to improve EF, specifically focusing on the potential of this type of intervention for children who have intellectual disabilities. We conclude that despite considerable discrepancies regarding reported intervention effects, these inconsistencies can be attributed to flaws in both program and study design. We discuss the steps needed to address these limitations and to facilitate the advancement of non-pharmaceutical interventions for children with intellectual disabilities.

Ambulatory mental health data demonstrates the high needs of people with an intellectual disability: results from the New South Wales intellectual disability and mental health data linkage project

OBJECTIVE

To investigate the ambulatory mental health service profile of persons with intellectual disability (ID) in a representative sample of New South Wales (NSW).

METHODS

A statistical linkage key was used to link the Disability Services Minimum Data Set (DS-MDS) and a community mental health services dataset (MH-COM) for a representative area of NSW for the period 2005-2010. Linkage was undertaken in four NSW local health districts (LHDs), covering 36.7% of the NSW population. The mental health profiles and service use characteristics of people with an ID were compared to mental health service users without an ID.

RESULTS

Of the 89,262 people in the MH-COM over this 6-year period, 1,459 people (1.6 %) were identified as having an ID. Compared to those without an ID, people with an ID were more likely to have psychotic disorders, developmental disorders and personality disorders, and more than twice as likely to have an 'unknown' diagnosis. Compared to those without an ID, people with an ID were less likely to have depressive disorders, adjustment disorders and other disorders. Service use profiles revealed that people with an ID had 1.6 times more face-to-face contacts, and a total face-to-face contact time which was 2.5 times longer than people without an ID.

CONCLUSIONS

Ambulatory mental health data from NSW indicates that people with an ID receive care for a distinct range of mental disorders, and experience uncertainty regarding their diagnosis. People with an ID have higher service needs which require recognition and the allocation of specific resources. Such data provide a suitable baseline for future evaluation of the impact of ambulatory mental health reforms for people with an ID.

Change in autism symptoms and maladaptive behaviors in adolescence and adulthood: the role of positive family processes

Little is known about outcomes for individuals with autism spectrum disorders (ASD) into adulthood. Several characteristics of individuals with ASD predict long-term outcomes, and the family environment may also play a role. The present study uses a prospective, longitudinal design to describe and predict trajectories of autism symptoms and maladaptive behaviors over 8.5 years in a large, community-based sample of adolescents and adults with ASD. Overall, autism symptoms and maladaptive behaviors were observed to improve over the study period. Above and beyond the adult's gender, age, and level of intellectual disability, greater improvements were associated with higher levels of maternal praise (based on maternal speech samples) and higher quality mother-child relationships. Implications for future research and intervention are discussed.