An investigation into the subjective wellbeing of people with an intellectual disability

Abstract

Over the past thirty years, subjective wellbeing (SWB) has emerged as a major theoretical construct within the quality of life literature. Moreover, it is now clear that understanding the SWB of people with intellectual disability is vital to our ability to plan and deliver quality services to such people. The theory of homeostatic control of SWB has not had extensive empirical testing among people with intellectual disability. This is despite such people having a far greater risk of homeostatic defeat than their non-disabled counterparts, due to greater levels of discrimination, abuse, victimisation and health issues. The purpose of this thesis is to test the theory of SWB homeostatic control for a sample of New Zealand people with mild to moderate intellectual disability, compared to non-disabled people. This involves three linked quantitative studies that investigate the internal buffers of self-esteem, control and optimism. The dependent variable is SWB as reported by participants. Study 1 explores the level of response scale complexity that people with intellectual disability can reliably use. Using a split-reversal research design participants were randomly assigned to two groups. Group A used a 7-point version of scales on Trial 1 and an 11-point version on Trial 2. Group B participants used the scales in reverse order. Results revealed a non-significant response difference between the two scale formats. The meaningfulness of participant‘s responses to both formats came from the finding that total mean scores obtained were within the normative range obtained for general population. It is concluded people with mild to moderate intellectual disability can respond to SWB scales at a level of complexity that is sensitive enough to record changes in SWB. Study 2 explores the maintenance of homeostatic control for people with mild to moderate intellectual disability compared to non-disabled people. This involves investigating the buffers of self-esteem, optimism and perceived control, which maintains a steady output of SWB. Results indicate the buffering system works differently for each group. People with intellectual disability use more avoidant control strategies, while non-disabled people used more approach control strategies. It is concluded that these different approaches to the maintenance of SWB are likely to be appropriate to the living circumstances of each group. Study 3 replicates and extends Study 2, to also determine whether the composition of homeostatically protected mood (HPMood), as parsimoniously represented by the affects content, happy and alert, is the same for intellectually disabled as it is for non-disabled people. Results generally confirm and extend Study 2 findings. The idea that SWB predominantly comprises positive affect was supported. Moreover, while the composition of HPMood differs somewhat between the two groups, the amount of variance explained in SWB by HPMood is comparable for both. In conclusion, normative SWB reported by people with intellectual disability suggests that due to the operation of HPMood and homeostasis, they generally feel good about themselves despite experiencing difficult life circumstances. Additionally, understanding the buffering system and SWB homeostatic control for people with intellectual disability, increases service providers and caregivers understanding of the type of conditions that are necessary to ensure homeostatic control of SWB remains undefeated, thus enhancing their life quality.