• Jes Sølgaard
  • Ask Magnus Johannesen Skifjeld
4. term, Psychology, Master (Master Programme)
Introduction: Problems with anger and aggression are usually common in people with intellectual disabilities, and it is often one of the most challenging aspects of the general treatment of this group. This study therefore sought to investigate the treatment effect of psychotherapy in reducing anger and aggression in people with intellectual disabilities.
Method: The chosen method for this study, was to conduct a systematic review and meta-analysis of the existing literature. A thorough literature search was conducted in six databases, supplemented by a control search of studies included in the list of refer-ences in other similar systematic reviews. The quality of all the included studies were assessed using The Cochrane Risk of Bias-tool, and the most important descriptive details were summarized for each study. The meta-analysis was conducted by calculat-ing the standardized mean differences of the studies, using a random effects model in Jamovi
Result: 14 different articles were included in the study, describing a total of 13 differ-ent studies. There were many substantial differences between the studies, in relation to their study design. Almost all of the studies described an observed effect of treatment, although their primary outcome measures were not always significant.
Analysis: The overall risk of bias was generally high in most of the studies. There were however some studies that had a more satisfying quality, with a lower risk of bias. The meta-analysis showed a large treatment effect of 0.84 dCohen (CI 95%: 0.58-1.10), but at the same time there was a substantial amount of heterogeneity (I2=49,46%). It was therefore necessary to discuss the validity of the meta-analysis.
Discussion: The big differences in quality and the heterogenicity between the included studies made it difficult to conclude an exact effect of psychotherapy. However, re-gardless of the heterogeneity and the overall quality, there was an observable effect in all except one study. There were also problems concerning the topics of anger and ag-gression, because of the uncertainty in how to understand and define these phenomena, which great doubts about the common understanding of these terms.
Conclusion: This study concludes that psychotherapy does seem to have a medium to large effect in reducing anger and aggression, but more high-quality research is needed to further conclude the exact effect.
Publication date31 May 2019
Number of pages84
ID: 304739898