A mixed methods investigation into Autism Plus and the impact of co-occurring conditions on the outcomes and support needs amongst adults with autism spectrum conditions

  • Michael Connolly

Student thesis: Doctoral Thesis


‘Autism Plus’ is a concept which relates to individuals with Autism Spectrum Condition (ASC) and co-occurring conditions (Gillberg & Fernell, 2014). Three studies reported in this thesis examined evidence for a key premise of Autism Plus, namely that individuals with Autism Plus experience poorer social and independent living outcomes and greater support needs compared to those with ‘Autism Only’ (i.e. those with ASC but no co-occurring diagnoses). Study One was a secondary analysis of survey data from secondary data analysis of 404 adults with autistic disorder (n = 82), Asperger’s/High-Functioning Autism (n = 236) and other ASCs (n = 86). A series of chi-square analyses comparing employment, relationship, residential and independent travel outcomes and service pattern use between those with Autism Plus and Autism Only. No group differences were found in employment or travel outcomes, though contrary to the premise of interest here, those with Autism Plus were found to be more likely to live independently and to be in long-term relationships. However, in line with the premise, those with Autism Plus were more likely to have used support services in the six months prior to data collection. In Study Two, logistic regression analyses focusing on the same sample explored whether Autism Plus may better predict poorer adult outcomes as part of a larger model accounting for age and autistic symptom severity. Findings indicated that Autism Plus was not a useful predictor of employment or independent travel outcomes as part of this model, though again indicated that those with Autism Plus were more likely to live independently and to be in long-term relationships. Other key findings indicated that outcomes were better amongst older individuals and those with milder autistic symptoms. Study Three aimed to gain greater insight into the ways in which co-occurring diagnoses could influence the lives of those with ASC through interviews with adults with Autism Plus. Analysis of accounts of lived experience using Interpretative Phenomenological Analysis (IPA) supported the view that the participants’ co-occurring symptoms added considerable disruption and difficulty to their lives, and at times could have a greater impact than their ASC symptoms. There was also evidence that within the context of Autism Plus, the severity of a co-occurring condition may be as important as its presence. Overall, the evidence reported here indicates that current conceptualisation of Autism Plus is limited in the extent to which it can predict those with ASC most likely to experience poor outcomes, though may be helpful in establishing those most likely to require support. Given the findings from Study Two and Three, it is recommended that a modified version of Autism Plus, which considers Autism Plus as an important component of a larger model and acknowledges co-occurring symptom severity, should be explored further.
Date of Award13 Aug 2021
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsUniversity of Strathclyde & Scottish Autism
SupervisorJim Boyle (Supervisor) & Louise Brown Nicholls (Supervisor)

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