Author
DIDDEN Robert; et al;
Behavioral treatment of challenging behaviors in individuals with mild mental retardation: meta-analysis of single-subject research.
Journal citation/publication details
American Journal on Mental Retardation, 111(4), July 2006, pp.290-298.
Summary
Eighty studies are included in this review, which concludes that there is good evidence to support the use of behavioural treatments (and, to a lesser extent, cognitive-behavioural treatments) to address challenging behaviours in people with mild learning difficulties. The results, however, are primarily derived from studies of children and adolescents in residential settings, and more research is needed to confirm whether they hold good with adults and in different settings.
Context
People with mild mental retardation are at greater risk of developing behavioural problems such as socially inappropriate behaviours, aggression, non-compliance and hyperactivity. Offending behaviour is also more common in this group than in the general population. Behavioural and psychotherapeutic treatments are now widespread, but 'controversy remains as to the evidence base of treatment procedures.especially in those who have mild mental retardation'.
Methods
What sources were used?
PsycINFO, ERIC ( Education Resources Information Center ) and Medline were searched, together with unspecified journals published between 1980 and 2005. The reference lists of relevant studies were also checked and 'unpublished studies were considered if enough information was provided'. However, no details of how these were identified (other than through database searches) are given.
What search terms/strategies were used?
No details are given.
What criteria were used to decide on which studies to include?
Studies were selected if they aimed to reduce an aspect of challenging behaviour and examined a behavioural and/or psychotherapeutic intervention in samples who: had an IQ between 55 and 75; or were described as having mild mental retardation/developmental disability; and/or were diagnosed as educationally mentally retarded. In addition, data had to be collected within baseline or control and treatment phases, and presented in a graph.
Who decided on their relevance and quality?
No details are given of the filtering of the initial search results against the inclusion criteria.
How many studies were included and where were they from?
Eighty studies met the inclusion criteria, comprising 133 comparisons for subsequent coding.
How were the study findings combined?
The first author coded all comparisons according to: year of publication; participants' age; gender; diagnosis; type of challenging behaviour; use and type of pre-treatment functional analysis; type of intervention; setting; study design; procedural reliability; recording reliability; follow-up; generalisation across settings and persons; and effectiveness of treatment. Effect sizes were calculated as PND (percentage of non-overlapping data) and PZD (percentage of zero data) values. The reliability of coding and calculation was checked in a sample of ten of the 80 studies.
Findings of the review
The analysis shows that challenging behaviour in people with mild mental retardation was effectively treated with predominantly behavioural interventions and, to a lesser extent, with cognitive-behavioural approaches such as anger management. The effect sizes were 'relatively large', with an average PND of 75% and PZD of 35%.
Typical interventions addressed physical aggression. combinations of aggressive behaviour and other externalising behaviours, and disruptive behaviours. They generally used differential reinforcement, extinction and differential reinforcement, and antecedent interventions, with only a minority of interventions involving punishment procedures such as contingent shock, loud noise or restraint.
The review does, however, have limitations. The majority of studies involved children and adolescents in residential settings, and more research is needed to explore whether the findings hold good with adults and/or in other settings. More research on challenging internalising behaviours, such as withdrawal and anxiety, are also needed. Interestingly, in this review studies conducted with the greatest methodological rigour produced the largest effect sizes (the opposite is often the case with meta-analyses, including examples from this field).
Authors' conclusions
The authors conclude that, bearing in mind the limitations of the review, 'there is a body of evidence that permits us to conclude that behavioural interventions for challenging behaviours are effective with people who have mild mental retardation.'
Implications for policy or practice
None are discussed.