The effectiveness of psychological therapies and therapists when working with adults with intellectual disabilities

Psychological therapy has not always been readily available for individuals with intellectual disabilities (ID) due to the belief that therapy was ineffective for this population group. This resulted in an avoidance of offering psychological therapy to clients with ID, often referred to as the 'unoffered chair' (Bender, 1993). Over time it has become evident that individuals with ID experience a wide range of emotions and often higher rates of mental health difficulties in comparison to non-disabled individuals. Psychological therapy is now increasingly offered to clients with ID and an abundance of psychological approaches are utilised in clinical practice. The first part of this thesis will systematically review existing systematic reviews on the effectiveness of psychological therapy for adults with ID and mental health difficulties. The intention was to bring the literature together and provide a useful document for clinical decision makers to easily compare and contrast the evidence. Twelve systematic reviews were identified which focused primarily on cognitive behavioural therapy, psychodynamic therapy, and third-wave therapies. This review tentatively suggested that psychological therapy can be effective for improving a variety of mental health difficulties in adults with ID, including reducing depression and anxiety. However, the review highlighted that the existing systematic reviews are of critically low quality. No conclusions could be made regarding which therapeutic approach works best for adults with ID, however, cognitive behavioural therapy reviews dominated the evidence base and were the only reviews to include comparison groups. The second part of this thesis explored the feasibility of an innovative Qmethodological design, with the hope that this would shed further light on what makes an effective therapist for adults with ID. Outside of the field of ID, a number of core qualities have been associated with increased therapist effectiveness. This has included the therapist's interpersonal skills, ability to be flexible and adaptive, and the ability to develop a therapeutic relationship with a broad range of clients. Twenty-seven clinical psychologists completed an online study and three distinct view points on what makes an effective therapist for this population were identified. However, delivering the Qsorting task online did not meet the feasibility criteria set out and resulted in a low participant sample size. Consequently, further statistical analysis was deemed inappropriate and recommendations are provided for future studies utilising this methodology. Together, the systematic review and research study provide further insights into psychological therapy for adults with ID and highlight the need for more research. The two studies indicate a lack of consensus regarding what works for clients with ID and also that there is not enough high-quality research regarding particular therapeutic modalities for clinicians to base their decisions on. If clinical psychologists vary considerably on what they believe is clinically effective in their work, then it is likely that their practice and possibly client outcomes, will subsequently vary also.