New research suggests that emotional and behavioral problems in children and adolescents with intellectual disability are common and may carry through to young adulthood. "These results provide evidence that the problem of psychopathology comorbid with intellectual disability is both substantial and persistent and suggest the need for effective mental health interventions," stated Stewart L. Einfeld, MD, of the University of Sydney, and colleagues. The results of their study were published in the October 25 JAMA.

HIGH PREVALENCE OF PSYCHOPATHOLOGY

The researchers examined the course of psychopathology in 578 children and adolescents with intellectual disability, ages 5 to 19.5, from the Australian Child to Adult Development Study. The participants were recruited from health, education, and family agencies that provided services to children with intellectual disability. These persons were followed up for 14 years, at four time waves of data collection. Data were obtained from 507 participants, with 84% of the initial participants from the first wave in 1991 and 1992 followed up from 2002 to 2003 during the fourth wave. The researchers analyzed the Developmental Behavior Checklist (DBC), a measure of psychopathology in young people with developmental disability completed by parents or other caregivers. Changes in the Total Behavior Problem Score and other subscale scores of the DBC were also analyzed.

The investigators found that the prevalence of participants meeting criteria for major psychopathology or definite psychiatric disorder was 41% at the start of the study, which then decreased to 31% from 2002 to 2003. This translated to a slow decline of 1.05 points per year on the DBC’s Total Behavior Problem Score. Overall severity of psychopathology was similar across mild to severe ranges of developmental disability; mean Total Behavior Problem Scores were approximately 44 points. In addition, there was a greater decrease in psychopathology among boys than among girls. Boys began with scores 2.61 points higher than girls’ scores at baseline and ended with scores 2.57 points lower than girls’ scores at the fourth wave.

There was a greater decrease in psychopathology among participants with mild developmental disability compared with those with severe or profound developmental disability. Children with mild developmental disability diverged from having scores 0.53 points lower at baseline, increasing to a difference of 6.98 points below participants with severe developmental disability by the fourth wave. Ten percent of the participants with psychopathology received mental health interventions during the study period.

"The overarching finding was one of a small, albeit significant, decline in severity of overall psychopathology over the 14 years in which the young participants with intellectual disability were followed up," Dr. Einfeld and colleagues stated. "Coupled with the absence of any relationship with age in the Total Behavior Problem Score, the small size of this decline demonstrates that psychopathology and behavioral disturbance in young people with intellectual disability is a phenomenon that largely persists through to young adulthood."

RECOMMENDATIONS TO REMEDY A PUBLIC HEALTH PROBLEM

Given these findings, the researchers presented a basis for planning to remedy the public health problem that psychopathology presents when it complicates intellectual disability.

First, due to the application of established cutoff scores for psychiatric disorder on the DBC Total Behavior Problem Score, "major behavioral and emotional disturbance is an added burden for approximately 40% of parents of children and adolescents with intellectual disability," the investigators noted. "Consequently, programs providing support for such parents need to include mental health interventions effective in altering the trajectories we have identified."

Also, as evidenced by the small degree of improvement during school years, Dr. Einfeld’s team pointed out that "educational settings for young individuals with intellectual disability will be required to contain high rates of psychopathology in their student groups, while attempting to maximize learning of independence skills." Mental health problems will also endanger the establishment of maximum vocational independence after the schooling period ends for adolescents. As a result, the researchers also recommended the requirement of effective mental health interventions and vocational flexibility to minimize "the number of young persons requiring disability support pensions, and the community cost thereof."

DIFFERENCES IN PSYCHOPATHOLOGY BETWEEN INDIVIDUALS

Regarding the differences between individuals in initial and subsequent levels of emotional and behavioral problems, Dr. Einfeld and colleagues pointed out that gender and severity of intellectual disability partially explained this statistically significant variance. In addition, previous findings that have shown the prepuberty predominance in males and the postpuberty predominance in females parallel the change in the course of psychopathology in girls and boys reported in the present study. However, the researchers also pointed out that persons with the most severe or profound intellectual disability decline less than do those with milder intellectual disability. One explanation for the variance present in Dr. Einfeld and colleagues’ findings "could be that those individuals with more severe congenital brain impairment are less affected by any rehabilitative or environmental influences on development."

Furthermore, reasons for the increase of one subscale on the DBC (social-relating disturbance), while the remaining four subscales (disruptive, self-absorbed, communication disturbance, anxiety) decreased, are currently unknown. "Perhaps the increase in anxiety for the girls with severe or profound intellectual disability and the increase in social-relating disturbance may reflect the increased demands on social skills experienced by young people with intellectual disability once they leave the protective school environment," according to the researchers. "This finding warrants further exploration, particularly in terms of examining other variables, such as the transitions experienced by young people as they leave school or move out of the family home."

Dr. Einfeld and colleagues stressed the importance of implementing effective mental health interventions, because of the high prevalence and persistence of psychopathology in their population of children and adolescents with intellectual disability. Such interventions "should include support, education, and skills training for their parents who are likely to be stressed by the burden of care," they noted. "Without effective interventions, these data could lead to the prediction that this sizable and neglected public health problem will also continue to be a burden on families, communities, and governments."

Suggested Reading
Einfeld SL, Piccinin AM, Mackinnon A, et al. Psychopathology in young people with intellectual disability. JAMA. 2006;296:1981-1989.

Return to table of contents