This study found that youths with ID or ASD comprise a substantial proportion of those served in public services systems caring for youths with mental health needs, particularly in the Serious Emotional Disturbance (SED) category of special education, as well as the public mental health and the child welfare systems. A second important finding was that youths with ID/ ASD in this sample differed from other youths in a number of ways: (a) They were younger on average, and more likely to be Caucasian, and of higher socioeconomic status. (b) They were more likely to be enrolled in the school SED system and less likely to be involved in the juvenile justice system. (c) They had significantly higher rates of externalizing psychiatric symptoms and diagnoses, and learning, developmental and medical problems. For youths with ID/ ASD, those involved in the child welfare system were less likely to meet criteria for an externalizing psychiatric diagnosis than those with ID/ ASD not enrolled in this system. A majority of youths with ID/ ASD enrolled in the alcohol/ drug and mental health systems were concurrently involved in another system. Across all systems except alcohol/ drug services, youths with ID/ASD were most likely to also be served by the mental health system.
The finding that approximately one fourth of youths in the school SED system had ID/ASD is consistent with the one other (albeit dated) study in this area, which reported that 22% of children with emotional disturbance referred for special education services had below average intellectual functioning (Mendelsohn & Jennings, 1986
). It is not clear why such a high proportion of youths with ID/ ASD are served under the SED special education category instead of autism or mental retardation categories. One possibility is that educational professionals view the youths’ behavioral problems as more important or impairing than developmental issues. Alternatively, behavioral problems related to developmental problems may have been misinterpreted as conduct problems, resulting in this placement. A critical examination of placement practices is warranted as an SED educational setting may not be an appropriate environment for youths with ID/ ASD.
Over 10% of youths in the mental health system had ID/ ASD. In California, as in many states, the mental health and developmental disability systems are administered separately. Unfortunately, although there has been more recent attention devoted to understanding psychiatric conditions in individuals with developmental disabilities such as ID and ASD, their diagnosis and treatment remain problematic (Rush, Bowman, Eidman, Toole, & Mortenson, 2004
). Providers may have difficulty recognizing mental disorders in this population (Rush et al., 2004
) or under-diagnose mental disorders in individuals with developmental disabilities due to diagnostic overshadowing of emotional disturbances by the presence of significant cognitive deficits (Reiss, 1993
; Reiss, Levitan, & Szyszko, 1982
). Training mental health clinicians to recognize and treat individuals who have psychiatric and developmental problems is a critical issue for improving services for this population (Moss, Emerson, Bouras, & Holland, 1997
The finding that more than 10% of youths in our sample who were active in the child welfare system had ID/ ASD is consistent with previous research suggesting that individuals with certain developmental disabilities are at increased risk for child abuse and neglect (Spencer et al., 2005
; Sullivan & Knutson, 2000
). For example, Mandell and colleagues (Mandell, Walrath, Manteuffel, Sgro, & Pinto-Martin, 2005b
) reported that almost 20% of children with autism had been physically or sexually abused. Developmental issues are not typically considered or identified in the child welfare system (Hibbard et al., 2007
), which may be particularly important when determining placement or services. Traditionally, the decision regarding whether to remove children from their homes of origin has focused on careful consideration of issues related to child safety, the impact of removal of the child on the family, parental rights, and permanence of children who have been abused or neglected rather than on developmental issues (Davidson-Arad, Englechin-Segal, & Wozner, 2003
). There are some preliminary data suggesting that youths with developmental delays may not fare as well in the foster care system as other youths and that specialized training may be needed to maximize the potential of these youths (Stahmer et al., in press
). Child welfare services, such as placement decisions, reunification efforts and parent training, should consider youths’ disabilities when helping parents to address their children’s needs.
Very few youths with ID/ ASD in this sample were active in the alcohol and drug system. This is consistent with research indicating that substance abuse disorders infrequently occur in people with ID (Glick & Zigler, 1995
; Reiss, 1990
) and that youths with ASDs are not likely to be referred for alcohol and drug treatment (Mandell et al., 2005a
). Likewise, very few youths were involved in the juvenile justice system. This is somewhat inconsistent with research indicating that a substantial proportion of children with a broad array of disabilities are involved in the juvenile justice system (Quinn et al., 2005
). It is possible that the low rate involved in juvenile justice relates to the specific disabilities examined or that developmental problems may not have not be identified and reported to parents of youths involved in this system.
The socio-demographic differences between youths with and without ID/ ASD are consistent with documented racial/ ethnic disparities in the timing of diagnosis in autism (Mandell, Listerud, Levy, & Pinto-Martin, 2002
) and service involvement, diagnosis, and treatment in youths with mental health problems (Garland et al., 2005
; Wood et al., 2005
; Yeh, McCabe, Hough, Dupuis, & Hazen, 2003
). In this sample, a higher proportion of youths with ID/ASD were Caucasian and had higher income compared to other youths. This is consistent with another recent study in Hong Kong in which parents of young children with ID had higher education and socioeconomic levels than parents of children without ID (Tang, Chen, Lau, & Wu, 2008)
. It may be that these disabilities go unrecognized in minority communities or that ethnic minority youths identified with these disabilities are more likely to be served in other special education categories not captured in the current study. The higher socioeconomic status of youths with ID/ASD suggests that families with greater resources may be more likely to either recognize or request assessment for developmental problems. A critical examination of these disparities is warranted.
The finding that three fourths of youths with ID/ASD met DSM-IV criteria for an externalizing diagnosis and had more severe behavior problems on the CBCL than other youths without an ID/ ASD is consistent with previous research (Kerker et al., 2004
; Leyfer et al., 2006
). In the current study, diagnosis on the DISC-IV required a least moderate impairment associated with the symptoms, indicating that these behavior problems may be beyond what would be expected based on having either ID or ASD. These youths also had higher rates of other learning, medical and developmental problems. These results provide additional support for the need for providers within these systems to understand how to serve individuals presenting with complex co-occurring psychiatric and developmental diagnoses.
Although, overall, youths with ID/ ASD had high rates of externalizing disorders across all service systems, youths enrolled in the child welfare system were less likely to be diagnosed with a psychiatric disorders. This finding may be explained by differences in the process of eligibility for services between systems. Specifically, the child welfare system differs from the others examined in that eligibility is based on a youth’s risk for maltreatment, not their behavior. Alternatively, there may be differences in characteristics of caregivers that influence their report on the CBCL and DISC-IV (on which externalizing diagnosis and problems were based). Further, youths involved in the mental health or the SED systems were more likely to meet criteria for conduct disorder. This finding may indicate that youths with ID/ ASD enrolled in these systems are likely to exhibit the most severe externalizing problems.
The last key finding of this study is that approximately one third of the sample was concurrently served in more than one system. The systems under study did not include the California Regional Centers, which coordinate and fund specialty care for individuals with developmental disabilities including ASDs and ID. Likewise, involvement in special education categories not related to emotional disorders (e.g., Autism, Mental Retardation) was not captured in this study. Therefore, it is likely that multiple service system involvement is actually much higher. This is consistent with previous research indicating that children with developmental disabilities are likely to be served by a high number of service providers at the same time (Kohler, 1999
; Thomas et al., 2007
), and suggests that, perhaps even more than for children without these disabilities, case coordination across systems is critical. Mechanisms for systematically coordinating between MR/DD and these other systems (especially mental health systems) are needed (Beasley & duPree, 2003
). Clear guidelines for system navigation are needed for both providers and for caregivers of youths with developmental disabilities. Finally, more information is needed on the types of intervention services youths with ID and ASD are receiving within each service systems, as there may be redundancies and/or gaps in care.
Some study limitations should be noted. First, these data were not collected to examine youths with ID/ ASD, so standardized measures to determine developmental status were not available. Therefore, the identification of ID/ ASD was based on parent report, which may underestimate prevalence as it is based on the parents’ knowledge of being identified as having ID or ASD by a professional. A related limitation is that the item used to identify those with ID also included “other developmental delay.” Because these groups are both considered to have ID in our local developmental disability system, the ID group in this study is broadly defined. Therefore, our findings can not be generalized to more precisely defined subgroups of children with developmental disabilities. Further, since the CHQ item used to identify children with ASD referred only to “autism,” children with other ASD diagnoses may have been missed, which potentially limits the generalizability of the results to the entire autism spectrum.
Another important limitation relates to the assessment of psychiatric disorders in youths with ID/ASD. As with most psychiatric diagnostic instruments, the psychometric properties of the DISC-IV are not available for youths with these disabilities (Leyfer et al., 2006)
. We also recognize there may be overlap between the behavioral characteristics of developmental disabilities and externalizing psychiatric disorders. However, we feel that identifying psychiatric problems according to DSM-IV criteria is an important first step in understanding psychiatric symptoms with these youths, especially when examining their involvement in public systems of care that serve youths with mental health problems or at risk for mental health problems. There was also no assessment of other mental health conditions as internalizing disorders (e.g. anxiety, depression) or other childhood disorders (e.g., Tourette’s, encopresis). Therefore, the overall estimated prevalence of co-occurring psychiatric diagnoses is likely much higher.
Another important limitation of this study is the low participation rate which potentially results in a biased sample. Although the sociodemographic characteristics of the participants were generally similar to the nonparticipants, the clinical characteristics are unknown. Additionally, this study examined youths sampled from public services in one metropolitan area almost a decade ago. Although the findings may not generalize to those served in other publicly funded systems or privately funded systems, the issues related to serving children with ID/ ASD likely remain relevant today as changes to the systems examined in our community have not directly targeted this population. Further, youths were sampled on the basis of their service involvement. For some participants, there may have been a lag between there service involvement and assessment. However, the random order of interviews may reduce any potential impact of time between involvement and assessment.
Despite these limitations, the results highlight the role of multiple public service systems in caring for youths with two of the most common developmental disabilities, ID and ASD. Because the five systems examined were not designed to serve individuals with developmental problems and many professionals in public service systems have limited training needed to work with this population (Matson & Sevin, 1994
), the findings support the need to build capacity in these systems to appropriately serve these youths and their families. Guidelines for system navigation for both families and for providers within the public systems are also clearly needed.