This is the first review of its kind that explores the prevalence of specific NDDs in Lac and highlight the adverse outcomes that some Lac with a NDD may experience. The aim of the study was to explore the prevalence of specific NDDs that are often very difficult to diagnose as a result of the similarities in characteristics and of which can be often missed, misdiagnosed or over diagnosed in the general population (26–30). Furthermore, it aimed to identify if there were any impacts on the Lac who had been diagnosed with a NDD. The results in this review support similar primary studies that have explored prevalence in Lac but also contribute to the dearth of literature that has explored the adverse outcomes on the Lac with a NDD.
Prevalence of NDDs
It was not a revelation that out of the twelve eligible studies, ADHD and ASD emerged as the most prominent and studied NDDs as this is reflective of the existing NDD literature available at this time. A much-needed research focus has been placed on both ASD and ADHD which has aided in highlighting the awareness of the prevalence, challenges and impacts on individuals with these NDDs (74–77) However, this review also highlights the dearth of literature conducted on the other specific NDDs of interest, such as dyslexia, tic disorders, dyspraxia and dyscalculia in relation to the Lac. It is well documented in literature that many of these NDDs co-occur with ADHD and ASD and prevalence rates for NDDs such as dyslexia in the general population are suggested to range from 5-17.5% (78). Dyslexia, itself can create challenges in reading, writing and processing information which are all key part of the learning process (79, 80). The impact on educational attainment, if not supported correctly can be detrimental for the child which can often lead to poor outcomes in education and have a direct impact on social mobility, which are both recognised concerns for many Lac on a global level (37).
The reasoning behind the high prevalence rates for ADHD (Lac 17.22 vs non-Lac 6.57%) and ASD (Lac 2.4 vs non-Lac 1.01%) found in Lac in this review is an area that requires more attention. A recent systematic review found similar global rates of ADHD in children and adolescents from the general population which support the results of this review for those categorised as non-Lac (81). However, an additional study explored mental health rates across nine countries and found a prevalence of 15.9% for ADHD in the general population which reflects more closely to the Lac percentage. Although a significant finding, this was based on survey results where self-reporting bias may have had an impact on the findings (82). Nevertheless, the prevalence rates for ADHD in Lac found in this review were significantly higher compared to their non-Lac peers. The same applies to the prevalence rates of ASD in Lac. However, it is important to note that this was only based on two studies. A recent systematic review found a global prevalence rate of 1% (1/100) in the general population, in which the majority of studies had included children, which supports the results of this review for non-Lac (83). Although, there is a dearth of literature on Lac with ASD, a study that explored awareness of autism within local authorities found a 3% prevalence rate of ASD in Lac and suggested that this may be an underestimation as a result of missing or unreported data.
Nevertheless, there are several factors to consider that might contribute to these differing prevalence rates between Lac and their non-Lac peers. It could be suggested that a reason for the lower prevalence rates in non-Lac might be attributed to clinicians under-diagnosing, misdiagnosing or missing ADHD or ASD within the general population. Many screening tools are still suggested to lack sufficient specificity and sensitivity to diagnose NDDs, particularly if we take gender, age or cultural differences into account (84–87). Females with a NDD, particularly ASD and ADHD often find it very difficult to attain an early diagnosis as a result of their differing display of behavioural symptomology compared to their male counterparts. Diagnostic assessments are improving and being enhanced to encompass the differences in the female phenotype but there are still areas that need addressing as suggested by other literature (23, 88–90). There are also demographic or geographical variations in the diagnostic process or improved documentation and data entry to consider (91–95). However, the same factors would apply for the prevalence rates for Lac.
Therefore, one could suggest that being a Lac may be a protective factor in attaining an early diagnosis and intervention as they are often embedded in health and social care services. Many children can be over-diagnosed in the general population as a result of male biased assessment tools, lack of knowledge and training and differing diagnostic pathways, and we must consider this same occurrence in the Lac population (27). However, for the Lac there are additional factors to consider that may contribute to this outcome. Professionals who are involved with the care of these children have to unravel their complex ND related characteristics with the characteristics associated with trauma and attachment as a result of ACEs. This complexity could create a confusion and uncertainty for many professionals and potentially hinder or influence their professional judgement when assessing these children. To add to this complexity, the diagnosis of children with NDDs are often attained through the evaluation of historical and current behaviour provided by the parent, combined with intensive educational and psychological testing. It is well recognised in Lac literature that even though reunification with the parent is priority, this does not always happen which leaves a significant lack of parental consent, parental involvement and contribution around childhood history which would cause a complex scenario when trying to assess these children with a NDD (96, 97).
There is also another factor to take into consideration and discourse for possible higher prevalence rates in this group and that is the hereditary or genetic origins associated with these NDDs. Many individuals in the general population have received an ADHD or ASD diagnosis much later in life after historically being misdiagnosed or diagnosed with other co-morbid conditions (98, 99). Therefore, it could be possible that the parents of these Lac may have fallen under the diagnostic radar and been misdiagnosed or even missed altogether as the need to treat other conditions may have overridden- more in-depth exploration of potential NDDs. Particularly, if we take into account that parents of Lac often have challenges in areas of mental health, substance misuse, domestic abuse and learning difficulties or disabilities which may be masking the characteristics of a ND (100, 101). The higher prevalence rates as already discussed require further investigation to ensure that the children/young adults who have been placed in the care system receive the most up to date specialist, holistic therapeutic interventions to enable them to flourish within society and attain positive health and social outcomes.
Adverse Outcomes for the Lac with a NDD
The second objective of the systematic review was to explore the impacts on the Lac with a NDD. Many Lac continue to attain poor health and social outcomes, which is a global concern for this vulnerable group (1, 3, 5, 6). This review found several studies that highlighted that Lac with ADHD, had higher mental health service usage, physical and emotional abuse, higher medication prescription, foster care involvement and criminal justice involvement compared to their non-Lac peers and even their Lac peers who had not been diagnosed with a NDD (63, 65, 68, 69, 72, 73).
It is well noted in research that Lac have a higher prevalence of mental health problems compared to their peers and some are embedded in services which provide them with direct access to appropriate health and social care provision (1, 3, 5). This might contribute to the findings of the dosREis et al (2001) and Tordön et al (2019) studies where mental health service usage was high. However, this finding that Lac with a NDD had a higher usage compared to their peers without a NDD is something to be further explored. Having NDDs, coupled with additional ACEs, and additional factors would have a significant impact on mental health needs. Additionally, many of these NDDs co-occur with debilitating anxiety and other mental disorders which could further contribute to their need for mental health services (102, 103).
The higher usage of mental health services for Lac could be a contributory factor to the findings detailed in the Mandell et al (2008) study. Medication prescription and usage has been noted as high in the Lac population in several studies (19, 104, 105). The number of children aged between 0–5 years who had been prescribed medication raises some concern. However, psychotropic medication as suggested by Mandell et al (2008) can be used for both mood-stabilizing and/or or antiepileptic properties and many autistic children have epilepsy and take these forms of medication (106). The medication used for some children with ASD and ADHD has raised some discourse within literature. Some studies have reported improved behaviours as a result of administering medications while others report negative associations and debilitating side effects (107–109). The long- term effects are still unknown and continue to be explored. However, they further propose that the high use of psychotropic drugs may be attributed to the changing environments that foster children often experience (96, 110). Changes to placements and routines for autistic Lac could exacerbate external behaviours and potentially lead to medicating the child to stabilise the care placement (68).
Only one study in this review found robust associations with foster care placement and having ADHD (65). However, Zill et al (2014) also found that 22% of foster-care children had been diagnosed with ADHD in their childhood. Another study found a high prevalence of ADHD (52%) within the sample Lac population but also added that only quarter of the parent foster carers involved had received interventions (111). Although, it is suggested that a multi modal support plan which includes pharmacological treatment should be considered when creating a care and support plan for children with ADHD. Interventions involving the child and parent/carer is equally important, to ensure that the plan meets the individualistic needs of the child with ADHD (112). Interestingly, in the Zill et al (2014) study it was children who had been adopted from foster care that had the highest prevalence of ADHD (36%)2. Several studies have also found similar rates in adopted children which is an area that requires further exploration as their individualistic needs would also need to be met (113–115).
Similar findings from the Ford et al (2007) study also found ADHD and ASD to be more prevalent in this care setting and suggested that the higher prevalence rates may be more attributed to the inadequate support and services available to families who have children with a NDD which has been highlighted in research (116–118). Additional literature supports these findings and ascertain that some parents voluntarily place their autistic children in foster care with no history of maltreatment, due to a lack of available and accessible specialist support or treatments (119). Many autistic children struggle with overwhelming sensory deficits and debilitating anxiety which can often result in self-injury, aggression or elopement (120). Therefore, it could be suggested that many parents would find it difficult to safeguard their children, especially if there is a lack of support. Autism can also frequently be associated with many other co-existing conditions such as OCD, eating disorders and anxiety, creating an even more complex situation and environment for the child and wider family (102, 103, 121). However, the González et al (2019) study detailed in the review proposed that children with NDDs such as ADHD or those that had ADHD characteristics might be more vulnerable to experiencing maltreatment, which conflicts with Cidav’s proposed no experience of maltreatment (Cidav et al., 2018). Nevertheless, one could suggest that this could be attributed to the fact that ADHD is a NDD that is often (not always) associated with more externalising behaviours and aggression than ASD, possibly increasing the risk of abuse.
Relevant, specialised support services are still scarce for many families pre/post diagnosis (116–118). From an economic and wellbeing perspective, specialist, holistic, early service provision is needed to better support these children. The average length of stay for autistic Lac is suggested to be 1.6 times longer than Lac without ASD and they are also less likely to be placed in a family setting (31% versus 53%) (122). More importantly, the kinship setting might provide a more stable placement setting as many autistic children react positively to familiar and recognisable surroundings; attributed to sharing familiarity with their biological kin (8).
Abuse and neglect are often the primary reasons for children entering the care system. Therefore, it was anticipated that some of these adverse outcomes would exist in literature on Lac with a NDD. However, the results highlight that Lac with a NDD may be at more risk of experiencing emotional and physical abuse compared to their peers and Lac peers. Emotional abuse has a wide definition in the context of social work and is often a major contributing factor for children becoming looked after (Trickett et al., 2009). It can be attributed to a variety of factors such as maltreatment, neglect, harmful or destructive social conditioning, poor socioeconomic environment or parental mental health (123–126). This could contribute to the findings presented in the González et al., (2019) study where emotional abuse had robust association with having an ADHD diagnosis. Although it is important to note that self-report bias could have influenced the results. It is well documented in research that children in the general population with ADHD are at higher risk of experiencing maltreatment compared to those individuals with no ADHD diagnosis (127, 128). González et al (2019) found that boys who were Lac were more likely to experience this form of abuse compared to their female counterparts. Another study found similar findings and further observed an association between maternal hyperactivity/impulsivity and male gender of the child which further increased the risk of emotional abuse (129). ADHD is often associated with externalised behaviours therefore this type of abuse could be further exacerbated and place these children at more risk if not supported correctly (128).
González et al (2019) also identified a negative association with physical abuse and ADHD and found that the prevalence of this abuse was much higher in Lac compared to their non-Lac peers and affected more girls. Physical abuse, alike emotional abuse is also often associated with the child who has ADHD in the general population (130, 131). Girls with ADHD can be vulnerable to intimate partner violence and physical maltreatment suggesting that they might be at more risk of experiencing physical abuse (132, 133). This is important to note and further explore for girls who are Lac and have ADHD, as this could place them at further risk if we factor in the addition of ACEs and their often-vulnerable environment.
Only one study in this review found a higher prevalence of criminal convictions in the Lac population compared to their non-Lac peers. The estimated criminal convictions in Lac with bipolar disorders and psychotic disorders, remained substantial even after regression analysis (Cote et al., 2018). Bipolar has been associated with criminal involvement in several studies however, research is still limited in respect of the Lac, particularly within this age group (134, 135). Characteristics associated with bipolar can be complex, very difficult to diagnose and can have varying subtypes such as Bipolar 1 and 11, which has not been detailed within this study (134, 136). Nevertheless, Bipolar is often diagnosed later in adulthood which could have attributed to the lack of findings (137). There have been studies that have explored bipolar in the criminal justice system and some have found that many of the adults had experienced ACE’s (138, 139). That is not suggesting that having bipolar and experiencing ACE’s place the individual at higher risk of being involved in the criminal justice system as there are so many confounding variables that evolve around this population. We know that unmanaged or unsupported ADHD or ASD can result in poor outcomes in drug use/addictive behaviour, antisocial behaviour, services use and occupation (140). Therefore, we must also consider that the lack of early diagnoses for these adults may have prohibited therapeutic intervention and support during their childhood. This lack of support would have significant safeguarding implications for the young adult with a NDD who has been placed in a juvenile facility (141–143). Many individuals with NDDs can self-harm and are frequently misunderstood in the youth justice system due to their cognitive differences. The behavioural characteristics can often be misinterpreted by their peers placing them in yet more vulnerable situations (141–143). More qualitative research on the experiences of adults with bipolar who were previously Lac would contribute to a better understanding of why some of these adults end up in the criminal justice system (144).
The aim of this review was to highlight to policies and stakeholders that prevalence of NDDs are high in this population and therefore require a specialist support system to meet the individualistic needs of this group. However, this can only be achieved by providing specialist services that have an in depth understanding of NDDs and currently there is no literature to support whether that is the case or not. It adds further value as it highlights the adverse outcomes that some of these children experience, even when compared to their own Lac peers with no diagnosed NDD. More research is needed to explore whether these children may be at more risk of experiencing these adverse outcomes.
Limitations of the review and to the evidence
Some limitations of this review were high heterogeneity between studies; subgroup analysis, and some study characteristics which may have influenced the results. The Lac and non-Lac groups detailed in this review, although detailed a priori in the protocol, could have been reunified with their biological parent/s However, reunification is not always sustained as a result of varying factors such as poor parental physical and mental health and continuous substance misuse abuse (7, 145). Nevertheless, Lac can transition into different care settings and the children in these articles may have previously entered the care setting prior to or after the study collated the data or the data did not disclose that the child had ever been in a care setting. Many children move in and out of the care system at different points in their lifetime which could have impacted on the results attained.
Only publications in the English language were searched. Language bias can often occur as a result of using this approach as the studies identified might not have been a complete, accurate representation of the evidence (146). The I₂ test was not scrutinised in the overall results as research proposes that this test can have low statistical power when there are a small number of studies and the confidence intervals (CI) large, which was the case for this review. More importance has been placed on the 95% CI (62).
A few of the studies were conducted across several European countries, however, eight of the studies reviewed were conducted in the USA. As each country has a different approach and process associated with becoming a Lac, this could have had an impact on the findings.
The high prevalence of ADHD found in this review could have been attributed to the majority of studies (n = 5/6) having been conducted in the USA as they have an overall higher prevalence of ADHD in the general population which might have influenced the results (147). However, the same higher prevalence in Lac compared to non-Lac does not differ.
There are also suggested limitations to attaining prevalence rates on NDDs based on either/or a diagnostic code, standardised diagnostic assessment tool or survey response. Varying factors such as self-reporting bias, coding of NDDs applied without clinician interviews and diagnostic codes would have changed over time for some of these NDDs (27). However, the review followed other studies of similar methodology and include in the collated characteristics the description of the tools, codes and diagnostic manual used for transparency purposes (40).
The findings from the Tordön et al (2019) was based on a small sample and was self-reported which could have resulted in self-reporting bias. Although, mental health service usage was high in Lac, the reasons for accessing these services could not be determined and therefore could be contributed to a multitude of complex factors associated with this vulnerable population.
To conclude this review there were a limited number of research studies comparing Lac versus non-Lac in this context. Therefore, the findings should be interpreted with caution as there are a multitude of contributory factors that could have attributed to these higher prevalence rates. It is important to acknowledge that the findings did not ascertain whether it was the actual NDD, lack of support, the complex dynamics surrounding the Lac, or a combination of both, that might have contributed to the increased adverse outcomes for these children.
The significant higher prevalence of NDDs in this population is something that stakeholders should make note of to ensure that specialist services and support are made available to this vulnerable population as early as possible. The adverse outcomes found raise even further discussion from a protective and safeguarding perspective.