The level of intellectual functioning for individuals with autism spectrum disorders is extremely variable, but estimates suggest that up to half of all those with an autism spectrum disorder also have an intellectual disability.
Whilst neurodevelopmental disorders affect children worldwide, it is thought that these might be more prevalent in lower- and middle-income countries compared to higher-income countries.
Most of the published research however has been carried out in the world’s wealthiest countries and evidence suggests that up to 75% of people with mental disorders in some LMICs do not receive any treatment services (Demyttenaere et al 2004). Specialists in such settings are a rare resource and so there is an interest in thinking about ways to build the capacities of non-specialists to provide support in low-resource settings.
The authors of this systematic review were interested in exploring the evidence-base for effectiveness of the provision of psychosocial interventions for learning disabilities and autism spectrum disorders by non-specialist providers. Evidence from low to middle income countries has been shown to lacking, and so the authors were interested to identify ways in which research in high income countries might usefully be adapted for implementation in low to middle income countries.
They therefore set out to provide “an appraisal of which interventions for children and adolescents with intellectual disabilities or lower-functioning autism spectrum disorders delivered by non-specialist care providers in community settings produce benefits in development, daily skills, school performance, behavior, or family outcomes when compared to either a no-treatment control group or treatment-as-usual comparator”
What they did was systematically search electronic databases to find prospective controlled studies.
They only included studies that compared a treatment to a control group that did not have the treatment, but unlike many systematic reviews, included non-randomised controlled studies on the understanding that to narrow the inclusion criteria to only those studies that were randomised to treatment and control might significantly reduce the number of studies that could be included.
The studies also had to report a psychosocial intervention, which they defined as therapy, education, training, or support aimed at improving behaviour, general overall development, or specific life skills without the use of medicines.
The intervention also had to be provided by a non-specialist, e.g. teacher, aide, parent, general practitioner, nurse practitioner, or local clinician). For the purposes of the review, psychiatrists, psychiatric nurse practitioners, psychologists, speech and language pathologists, occupational therapists, and physical therapists were considered specialist providers.
They found over 20,000 records in the first search, but following de-duplication and the application of the inclusion criteria, they were left with 234 full papers, of which 34 articles describing 29 studies involving 1,305 participants were included.
One of the things the researchers did was to calculate effect sizes of the intervention. Effect sizes indicate the following effects of interventions
- 0.2 indicates no effect
- 0.2–0.5 indicates a small effect
- greater than 0.5 indicates a medium-to-large effect
They actually found over half the studies (15 of 29) were randomised controlled trials and three-quarters of the effect size estimates were positive, and nearly half were greater than 0.50, indicating medium to large effects.
When looking at studies that reported behavioural analytic interventions focused on improving socially significant behaviour they found the largest effect sizes were seen for development and daily skills.
When looking at interventions like cognitive rehabilitation, training, and support which focus on the re-learning of lost or altered cognitive skills, they found these produced good improvements in developmental outcomes as measured on IQ tests in children aged 6–11 years old.
They also looked at training interventions for parents aiming to offer guidance for parents on how to provide therapy services for their child and these appeared to have strong effects on developmental, behavioural, and family outcomes.
Conclusion and comment
This is a well conducted systematic review that although widening inclusion criteria to include non-randomised studies, did in fact report on a good many such RCTs within the review. The findings show a good range of psychosocial interventions that can be effectively provided by non-specialist service providers.
One of the major issues with the review is that it is looking to find effective interventions in low to middle income countries, but is using evidence from high income countries as a guide. Very few of the included studies came from low- and middle-income countries. This means of course that the findings may not be generalizable to those children living in those resource-limited setting.
One of the interesting issues discussed in the review is that studies providing high treatment densities often involved significant supervision of the treatment providers by highly trained professionals, but the studies themselves did not provide sufficient detail of this to enable any conclusions to be drawn about its impact on outcomes and effect sizes, but this would be something to consider in future research.
The authors conclude though that given specialists are scarce in many resource-limited settings, the findings of the review provide good evidence for the potential success of a range of interventions by non-specialists to improve outcomes for children with learning disabilities or lower-functioning Autism Spectrum Disorders in low- and middle-income countries.
Non-Specialist Psychosocial Interventions for Children and Adolescents with Intellectual Disability or Lower-Functioning Autism Spectrum Disorders: A Systematic Review, Reichow B et al., in PLoS Med 10(12)
Reference: Demyttenaere K, Bruffaerts R, Posada-Villa J, Gasquet I, Kovess V, et al. (2004) Prevalence, severity, and unmet need for treatment of mental disorders in the World Health Organization, World Mental Health Surveys. JAMA 291: 2581–2590.