Emma Honey - Academia.edu (original) (raw)
Papers by Emma Honey
Frontiers in Rehabilitation Sciences
BackgroundDemand for diagnostic assessment in children with possible autism has recently increase... more BackgroundDemand for diagnostic assessment in children with possible autism has recently increased significantly. Services are under pressure to deliver timely and high-quality diagnosis, following National Institute and Care Excellence multidisciplinary assessment guidelines. This UK National Health Service study aimed to answer: how many hours of health professional time are required to deliver autism diagnostic assessment, and how much does this cost?.MethodCase notes of 20 children (1–16 yrs.) from 27 NHS trusts, assessed through an autism diagnostic pathway in the previous year, were examined retrospectively. Data included: hours of professional time, diagnostic outcome. Assessment costs calculated using standardised NHS tariffs.Results488 children (aged 21–195 months, mean 82.9 months, SD 39.36) from 22 Child Development Services (CDS), four Child and Adolescent Mental Health Services (CAMHS) and one tertiary centre; 87% were either under 5 (36%) or 5 to 11 years (51%). Childr...
Clinical Psychology Forum
This article describes a systematic investigation into intolerance of uncertainty (IU) behaviours... more This article describes a systematic investigation into intolerance of uncertainty (IU) behaviours. This involved systematic searches of IU behaviours, developing an expert consensus of the different types of IU behaviour and classifying behaviours into these categories.
Developmental Psychology Forum
This record contains two files comprising the material used in study 2 of Stuart, L., Grahame, V.... more This record contains two files comprising the material used in study 2 of Stuart, L., Grahame, V., Honey, E., & Freeston, M. (2020). Intolerance of uncertainty and anxiety as explanatory frameworks for extreme demand avoidance in children and adolescents. <i>Child and Adolescent Mental Health</i>, <i>25</i>(2), 59-67.The first file is a semi-structured interview used to explore a caregiver's perception of their child's behaviour in uncertain situations. The second provides a range of examples of uncertain situations where a child or young person may experience distress related to uncertainty; these examples may be used to prompt the participant.
Additional file 1. SPIRIT Checklist.
Additional file 2. Ethical approval documentation. HRA ethical approval.
sagepub.co.uk/journalsPermissions.nav
Journal of Policy and Practice in Intellectual Disabilities, 2021
Child and Adolescent Mental Health, 2020
Child and Adolescent Mental Health, 2020
Many children with austism spectrum disorder (ASD) show difficulties containing anxiety, acute di... more Many children with austism spectrum disorder (ASD) show difficulties containing anxiety, acute distress, behavioural avoidance or control, and sometimes to an extreme degree. Not nearly enough is known about the variety of likely origins of such presentations or their course. Pathological Demand Avoidance (PDA) has been advocated as a discrete developmental syndrome explaining such characteristics when extreme, but its status as an entity is controversial and to date poorly evidenced. Stuart et al. make one of the first studies into factors underlying PDA, by testing Intolerance of uncertainty and anxiety as explanatory paradigms. There is a circularity in their sampling design and common respondent methods, which, alongside the uncertain status of PDA itself, inevitably limits firm conclusions from their study. However, they do develop important concepts and hypotheses that could and should be tested in representative samples across ASD, using comparative, longitudinal and interven...
Child and Adolescent Mental Health, 2019
Background: Pathological demand avoidance (PDA) is a proposed subtype of autism spectrum disorder... more Background: Pathological demand avoidance (PDA) is a proposed subtype of autism spectrum disorder (ASD), characterised by extreme avoidance of demands. Demand avoidant behaviour has been proposed to be driven by an anxious need to be in control, although has never been explicitly studied. Emerging evidence suggests intolerance of uncertainty (IU) and anxiety may explain the behaviours seen in ASD. We propose these concepts may be useful starting points for furthering understanding of PDA. Methods: In Study 1, quantitative methods examined the relationship between PDA, IU and anxiety using data collected in an online survey (N = 214). The sample included cases with clinically diagnosed PDA (n = 69) and those with no clinical diagnosis but parent-identified features of PDA (n = 151). 'Children with a diagnosis of PDA scored significantly higher on the IUS-P (t(212) = 2.45, p < .05) compared to those without a diagnosis of PDA. PDA diagnosis did not impact on scores on any other measure.' In Study 2, a selection of Study 1 participants (n = 11) were followed up with a telephone interview to gain descriptive data relating to PDA and its association with IU and anxiety. Results: Regression analyses indicate that demand avoidant behaviour can be conceptualised in part as a possible attempt to increase certainty and predictability to alleviate increasing anxiety. Children and young people with PDA employed varying strategies to manage IU depending on the level of demand presented and degree of anxiety generated. These strategies can be represented by different features of the behaviour profile seen in PDA (control behaviour, withdrawal to fantasy, and meltdown). These behavioural features of PDA showed differential relationships with IU and anxiety, although all were predicted by IU, only meltdown demonstrated a mediation effect by anxiety. Conclusions: This study represents one of the first attempts to conceptualise and understand the behavioural features of the PDA profile in children and young people. It builds upon emerging evidence from the ASD literature that IU is a relevant construct for conceptualising demand avoidant behaviour in children who show PDA behaviour. This has potential clinical implications for the assessment and management of PDA in children and young people. Key Practitioner Message • Demand avoidant behaviour in PDA has been proposed to be driven by an anxious need to be in control, although has never been explicitly studied. • This paper highlights that demand avoidant behaviour in children with PDA can be conceptualised as an attempt to increase certainty and predictability to alleviate increasing anxiety. • This study builds upon emerging evidence from the ASD literature that intolerance of uncertainty (IU) is a relevant construct for conceptualising demand avoidant behaviour in children with PDA. • If IU and anxiety are at the heart of understanding EDA behaviours, it follows that anxiety and IU-based treatment approaches may be beneficial for these children.
Journal of Autism and Developmental Disorders, 2019
We examined the feasibility and acceptability of using an immersive virtual reality environment (... more We examined the feasibility and acceptability of using an immersive virtual reality environment (VRE) alongside cognitive behaviour therapy (CBT) for young people with autism experiencing specific phobia. Thirty-two participants were randomised to treatment or control. Treatment involved one session introducing CBT techniques and four VRE sessions, delivered by local clinical therapists. Change in target behaviour was independently rated. Two weeks after treatment, four treatment participants (25%) and no control participants were responders; at 6 months after treatment, six (38%) treatment and no control participants were responders. At 6 months post-treatment, symptoms had worsened for one treatment and five control (untreated) participants. Brief VRE exposure with CBT is feasible and acceptable to deliver through child clinical services and is effective for some participants.
Journal of Autism and Developmental Disorders, 2017
example, reporting the need to restrict certain aspects of family life such as family days out an... more example, reporting the need to restrict certain aspects of family life such as family days out and holidays (Hutton and Caron 2005; Montes and Halterman 2007). In addition, research has shown autistic adults are at increased risk of experiencing mental health problems, with anxiety difficulties reported as common amongst autistic adults and their family members (Davis et al. 2011; Van Bourgondien et al. 2014). Sterling et al. (2008) report in a sample of autistic 18-44 year olds that around 35% had anxiety, whilst Mazefsky et al. (2008) report 77% of autistic adults in their sample met criteria for an anxiety disorder. When mental health difficulties are present, this can be an additional barrier in addition to autism specific barriers towards independence for autistic adults (Smith and Philippen 2005), further increasing the need for support from others. Family Members/Caregivers of Autistic Adults Hare et al. (2004) interviewed families of 26 autistic adults, and found parental emotional distress was prominent and directly associated with unmet need of the autistic family member. One of the unmet needs identified by family members was the capability to plan for their relatives' future and the majority of participants expressed concern about the future for their autistic relative, due to the lack of service provision. Krauss et al. (2005) explored the positive and negative experiences of mothers of autistic adults. They directly compared those who lived in the family home versus those in residential care. Those whose relative lived with them in the family home reported experiencing daily stress, whereas Abstract Family members are often the primary caregiver for autistic adults and this responsibility may impact on the carer's wellbeing and quality of life. 109 family members of autistic adults completed an online survey assessing their wellbeing relating to their caring role for their autistic relative. Family members who were supporting an autistic relative with co-occurring mental health difficulties and who they reported as unprepared for the future, self-reported higher levels of worry, depression, anxiety and stress, and poorer quality of life. These findings emphasise the importance of support for family members of autistic adults, whether through external services to support their relative or individual mental health support for the carer.
Journal of Autism and Developmental Disorders, 2017
In order to investigate the experience of anxiety and restricted and repetitive behaviours (RRB) ... more In order to investigate the experience of anxiety and restricted and repetitive behaviours (RRB) in young people with ASD, nineteen families with young people with ASD aged between 13 and 20 years completed questionnaire measures of RRB, anxiety, and intolerance of uncertainty. Ten young people also completed a novel semi-structured interview exploring an individualised example of an RRB. Findings demonstrated that young people with ASD can self-report and show insight in to their RRB, and replicated previous findings based on parent report showing a significant positive relationship between RRB and anxiety. This is the first evidence of young person self-report using both quantitative and qualitative data and indicates a range of reasons why young people may engage in RRB.
Autism Research, 2016
Sensory atypicalities are a common feature of autism spectrum disorder (ASD). To date, the relati... more Sensory atypicalities are a common feature of autism spectrum disorder (ASD). To date, the relationship between sensory atypicalities in dyads of children with ASD and their parents has not been investigated. Exploring these relationships can contribute to an understanding of how phenotypic profiles may be inherited, and the extent to which familial factors might contribute towards children's sensory profiles and constitute an aspect of the broader autism phenotype (BAP). Parents of 44 children with ASD and 30 typically developing (TD) children, aged between 3 and 14 years, participated. Information about children's sensory experiences was collected through parent report using the Sensory Profile questionnaire. Information about parental sensory experiences was collected via self‐report using the Adolescent/Adult Sensory Profile. Parents of children with ASD had significantly higher scores than parents of TD children in relation to low registration, over responsivity, and ta...
Journal of Autism and Developmental Disorders, 2016
Autism Research, 2016
Many children with autism spectrum disorder (ASD) experience high levels of anxiety. A widely use... more Many children with autism spectrum disorder (ASD) experience high levels of anxiety. A widely used measure for typically developing children is the Revised Child Anxiety and Depression Scale (RCADS). However, such anxiety measures may require adaptation to accommodate characteristics of those with ASD. An adapted version of the RCADS was created based on empirical evidence of anxiety phenomenology in ASD, which included additional items related to sensory anxiety, intolerance of uncertainty, and phobias. Content validity was refined during focus groups with parents. Polychoric factor analysis was undertaken on data from 170 children with ASD, aged 8‐16, and their parents. This process resulted in the creation of a new 24 item scale (self and parent report) each with four subscales: Performance Anxiety, Uncertainty, Anxious Arousal, and Separation Anxiety, with evidence of good reliability and validity. The freely available Anxiety Scale for Children ‐ ASD, Parent and Child versions ...
Journal of Applied Research in Intellectual Disabilities, 2016
BackgroundAnxiety is a common problem for children with autism spectrum disorder (ASD). Recent re... more BackgroundAnxiety is a common problem for children with autism spectrum disorder (ASD). Recent research indicates that intolerance of uncertainty (IU) may be an important aspect of anxiety for this population. IU is the belief that uncertainty is upsetting, and not knowing what is going to happen is negative. There is little known about the phenomenology of IU in children with ASD. We therefore present data from parent focus groups exploring this concept in children with ASD.MethodsParticipants were asked to differentiate IU from dislike of change and fear, and to discuss examples of IU and the strategies they use to manage it. Their experiences of IU and strategies are presented.ResultsIU was evident across novel and familiar situations and parents used a variety of strategies to manage IU. Their experiences of IU and strategies used are presented.ConclusionsParticipants were able to identify and provide examples of IU suggesting that it is a recognizable construct among children w...
Review Journal of Autism and Developmental Disorders, 2015
Existing evidence suggests that there is a relationship between sensory processing difficulties a... more Existing evidence suggests that there is a relationship between sensory processing difficulties and the clinical and non-clinical features of autism spectrum disorder (ASD). The current review aimed to evaluate evidence of the psychological correlates of sensory processing patterns in individuals with ASD. Primary studies investigating sensory processing patterns in children and adolescents with ASD were identified through systematic searches of electronic databases and evaluated for methodological rigor and reporting quality. In 21 studies, associations between sensory processing patterns and psychological correlates were found. Sensory hyporesponsiveness was correlated with core features of ASD. Social awareness difficulties and affective disorders were associated with hyperresponsiveness. Mixed results were found for repetitive behaviours. Further research is needed to confirm, clarify and extend these findings.
Frontiers in Rehabilitation Sciences
BackgroundDemand for diagnostic assessment in children with possible autism has recently increase... more BackgroundDemand for diagnostic assessment in children with possible autism has recently increased significantly. Services are under pressure to deliver timely and high-quality diagnosis, following National Institute and Care Excellence multidisciplinary assessment guidelines. This UK National Health Service study aimed to answer: how many hours of health professional time are required to deliver autism diagnostic assessment, and how much does this cost?.MethodCase notes of 20 children (1–16 yrs.) from 27 NHS trusts, assessed through an autism diagnostic pathway in the previous year, were examined retrospectively. Data included: hours of professional time, diagnostic outcome. Assessment costs calculated using standardised NHS tariffs.Results488 children (aged 21–195 months, mean 82.9 months, SD 39.36) from 22 Child Development Services (CDS), four Child and Adolescent Mental Health Services (CAMHS) and one tertiary centre; 87% were either under 5 (36%) or 5 to 11 years (51%). Childr...
Clinical Psychology Forum
This article describes a systematic investigation into intolerance of uncertainty (IU) behaviours... more This article describes a systematic investigation into intolerance of uncertainty (IU) behaviours. This involved systematic searches of IU behaviours, developing an expert consensus of the different types of IU behaviour and classifying behaviours into these categories.
Developmental Psychology Forum
This record contains two files comprising the material used in study 2 of Stuart, L., Grahame, V.... more This record contains two files comprising the material used in study 2 of Stuart, L., Grahame, V., Honey, E., & Freeston, M. (2020). Intolerance of uncertainty and anxiety as explanatory frameworks for extreme demand avoidance in children and adolescents. <i>Child and Adolescent Mental Health</i>, <i>25</i>(2), 59-67.The first file is a semi-structured interview used to explore a caregiver's perception of their child's behaviour in uncertain situations. The second provides a range of examples of uncertain situations where a child or young person may experience distress related to uncertainty; these examples may be used to prompt the participant.
Additional file 1. SPIRIT Checklist.
Additional file 2. Ethical approval documentation. HRA ethical approval.
sagepub.co.uk/journalsPermissions.nav
Journal of Policy and Practice in Intellectual Disabilities, 2021
Child and Adolescent Mental Health, 2020
Child and Adolescent Mental Health, 2020
Many children with austism spectrum disorder (ASD) show difficulties containing anxiety, acute di... more Many children with austism spectrum disorder (ASD) show difficulties containing anxiety, acute distress, behavioural avoidance or control, and sometimes to an extreme degree. Not nearly enough is known about the variety of likely origins of such presentations or their course. Pathological Demand Avoidance (PDA) has been advocated as a discrete developmental syndrome explaining such characteristics when extreme, but its status as an entity is controversial and to date poorly evidenced. Stuart et al. make one of the first studies into factors underlying PDA, by testing Intolerance of uncertainty and anxiety as explanatory paradigms. There is a circularity in their sampling design and common respondent methods, which, alongside the uncertain status of PDA itself, inevitably limits firm conclusions from their study. However, they do develop important concepts and hypotheses that could and should be tested in representative samples across ASD, using comparative, longitudinal and interven...
Child and Adolescent Mental Health, 2019
Background: Pathological demand avoidance (PDA) is a proposed subtype of autism spectrum disorder... more Background: Pathological demand avoidance (PDA) is a proposed subtype of autism spectrum disorder (ASD), characterised by extreme avoidance of demands. Demand avoidant behaviour has been proposed to be driven by an anxious need to be in control, although has never been explicitly studied. Emerging evidence suggests intolerance of uncertainty (IU) and anxiety may explain the behaviours seen in ASD. We propose these concepts may be useful starting points for furthering understanding of PDA. Methods: In Study 1, quantitative methods examined the relationship between PDA, IU and anxiety using data collected in an online survey (N = 214). The sample included cases with clinically diagnosed PDA (n = 69) and those with no clinical diagnosis but parent-identified features of PDA (n = 151). 'Children with a diagnosis of PDA scored significantly higher on the IUS-P (t(212) = 2.45, p < .05) compared to those without a diagnosis of PDA. PDA diagnosis did not impact on scores on any other measure.' In Study 2, a selection of Study 1 participants (n = 11) were followed up with a telephone interview to gain descriptive data relating to PDA and its association with IU and anxiety. Results: Regression analyses indicate that demand avoidant behaviour can be conceptualised in part as a possible attempt to increase certainty and predictability to alleviate increasing anxiety. Children and young people with PDA employed varying strategies to manage IU depending on the level of demand presented and degree of anxiety generated. These strategies can be represented by different features of the behaviour profile seen in PDA (control behaviour, withdrawal to fantasy, and meltdown). These behavioural features of PDA showed differential relationships with IU and anxiety, although all were predicted by IU, only meltdown demonstrated a mediation effect by anxiety. Conclusions: This study represents one of the first attempts to conceptualise and understand the behavioural features of the PDA profile in children and young people. It builds upon emerging evidence from the ASD literature that IU is a relevant construct for conceptualising demand avoidant behaviour in children who show PDA behaviour. This has potential clinical implications for the assessment and management of PDA in children and young people. Key Practitioner Message • Demand avoidant behaviour in PDA has been proposed to be driven by an anxious need to be in control, although has never been explicitly studied. • This paper highlights that demand avoidant behaviour in children with PDA can be conceptualised as an attempt to increase certainty and predictability to alleviate increasing anxiety. • This study builds upon emerging evidence from the ASD literature that intolerance of uncertainty (IU) is a relevant construct for conceptualising demand avoidant behaviour in children with PDA. • If IU and anxiety are at the heart of understanding EDA behaviours, it follows that anxiety and IU-based treatment approaches may be beneficial for these children.
Journal of Autism and Developmental Disorders, 2019
We examined the feasibility and acceptability of using an immersive virtual reality environment (... more We examined the feasibility and acceptability of using an immersive virtual reality environment (VRE) alongside cognitive behaviour therapy (CBT) for young people with autism experiencing specific phobia. Thirty-two participants were randomised to treatment or control. Treatment involved one session introducing CBT techniques and four VRE sessions, delivered by local clinical therapists. Change in target behaviour was independently rated. Two weeks after treatment, four treatment participants (25%) and no control participants were responders; at 6 months after treatment, six (38%) treatment and no control participants were responders. At 6 months post-treatment, symptoms had worsened for one treatment and five control (untreated) participants. Brief VRE exposure with CBT is feasible and acceptable to deliver through child clinical services and is effective for some participants.
Journal of Autism and Developmental Disorders, 2017
example, reporting the need to restrict certain aspects of family life such as family days out an... more example, reporting the need to restrict certain aspects of family life such as family days out and holidays (Hutton and Caron 2005; Montes and Halterman 2007). In addition, research has shown autistic adults are at increased risk of experiencing mental health problems, with anxiety difficulties reported as common amongst autistic adults and their family members (Davis et al. 2011; Van Bourgondien et al. 2014). Sterling et al. (2008) report in a sample of autistic 18-44 year olds that around 35% had anxiety, whilst Mazefsky et al. (2008) report 77% of autistic adults in their sample met criteria for an anxiety disorder. When mental health difficulties are present, this can be an additional barrier in addition to autism specific barriers towards independence for autistic adults (Smith and Philippen 2005), further increasing the need for support from others. Family Members/Caregivers of Autistic Adults Hare et al. (2004) interviewed families of 26 autistic adults, and found parental emotional distress was prominent and directly associated with unmet need of the autistic family member. One of the unmet needs identified by family members was the capability to plan for their relatives' future and the majority of participants expressed concern about the future for their autistic relative, due to the lack of service provision. Krauss et al. (2005) explored the positive and negative experiences of mothers of autistic adults. They directly compared those who lived in the family home versus those in residential care. Those whose relative lived with them in the family home reported experiencing daily stress, whereas Abstract Family members are often the primary caregiver for autistic adults and this responsibility may impact on the carer's wellbeing and quality of life. 109 family members of autistic adults completed an online survey assessing their wellbeing relating to their caring role for their autistic relative. Family members who were supporting an autistic relative with co-occurring mental health difficulties and who they reported as unprepared for the future, self-reported higher levels of worry, depression, anxiety and stress, and poorer quality of life. These findings emphasise the importance of support for family members of autistic adults, whether through external services to support their relative or individual mental health support for the carer.
Journal of Autism and Developmental Disorders, 2017
In order to investigate the experience of anxiety and restricted and repetitive behaviours (RRB) ... more In order to investigate the experience of anxiety and restricted and repetitive behaviours (RRB) in young people with ASD, nineteen families with young people with ASD aged between 13 and 20 years completed questionnaire measures of RRB, anxiety, and intolerance of uncertainty. Ten young people also completed a novel semi-structured interview exploring an individualised example of an RRB. Findings demonstrated that young people with ASD can self-report and show insight in to their RRB, and replicated previous findings based on parent report showing a significant positive relationship between RRB and anxiety. This is the first evidence of young person self-report using both quantitative and qualitative data and indicates a range of reasons why young people may engage in RRB.
Autism Research, 2016
Sensory atypicalities are a common feature of autism spectrum disorder (ASD). To date, the relati... more Sensory atypicalities are a common feature of autism spectrum disorder (ASD). To date, the relationship between sensory atypicalities in dyads of children with ASD and their parents has not been investigated. Exploring these relationships can contribute to an understanding of how phenotypic profiles may be inherited, and the extent to which familial factors might contribute towards children's sensory profiles and constitute an aspect of the broader autism phenotype (BAP). Parents of 44 children with ASD and 30 typically developing (TD) children, aged between 3 and 14 years, participated. Information about children's sensory experiences was collected through parent report using the Sensory Profile questionnaire. Information about parental sensory experiences was collected via self‐report using the Adolescent/Adult Sensory Profile. Parents of children with ASD had significantly higher scores than parents of TD children in relation to low registration, over responsivity, and ta...
Journal of Autism and Developmental Disorders, 2016
Autism Research, 2016
Many children with autism spectrum disorder (ASD) experience high levels of anxiety. A widely use... more Many children with autism spectrum disorder (ASD) experience high levels of anxiety. A widely used measure for typically developing children is the Revised Child Anxiety and Depression Scale (RCADS). However, such anxiety measures may require adaptation to accommodate characteristics of those with ASD. An adapted version of the RCADS was created based on empirical evidence of anxiety phenomenology in ASD, which included additional items related to sensory anxiety, intolerance of uncertainty, and phobias. Content validity was refined during focus groups with parents. Polychoric factor analysis was undertaken on data from 170 children with ASD, aged 8‐16, and their parents. This process resulted in the creation of a new 24 item scale (self and parent report) each with four subscales: Performance Anxiety, Uncertainty, Anxious Arousal, and Separation Anxiety, with evidence of good reliability and validity. The freely available Anxiety Scale for Children ‐ ASD, Parent and Child versions ...
Journal of Applied Research in Intellectual Disabilities, 2016
BackgroundAnxiety is a common problem for children with autism spectrum disorder (ASD). Recent re... more BackgroundAnxiety is a common problem for children with autism spectrum disorder (ASD). Recent research indicates that intolerance of uncertainty (IU) may be an important aspect of anxiety for this population. IU is the belief that uncertainty is upsetting, and not knowing what is going to happen is negative. There is little known about the phenomenology of IU in children with ASD. We therefore present data from parent focus groups exploring this concept in children with ASD.MethodsParticipants were asked to differentiate IU from dislike of change and fear, and to discuss examples of IU and the strategies they use to manage it. Their experiences of IU and strategies are presented.ResultsIU was evident across novel and familiar situations and parents used a variety of strategies to manage IU. Their experiences of IU and strategies used are presented.ConclusionsParticipants were able to identify and provide examples of IU suggesting that it is a recognizable construct among children w...
Review Journal of Autism and Developmental Disorders, 2015
Existing evidence suggests that there is a relationship between sensory processing difficulties a... more Existing evidence suggests that there is a relationship between sensory processing difficulties and the clinical and non-clinical features of autism spectrum disorder (ASD). The current review aimed to evaluate evidence of the psychological correlates of sensory processing patterns in individuals with ASD. Primary studies investigating sensory processing patterns in children and adolescents with ASD were identified through systematic searches of electronic databases and evaluated for methodological rigor and reporting quality. In 21 studies, associations between sensory processing patterns and psychological correlates were found. Sensory hyporesponsiveness was correlated with core features of ASD. Social awareness difficulties and affective disorders were associated with hyperresponsiveness. Mixed results were found for repetitive behaviours. Further research is needed to confirm, clarify and extend these findings.