"Quality of life of adults on the autism spectrum is lower than that of typically developing adults, when measured with tools designed for the general population."
That was one of the primary conclusions reached by Michael Ayres and colleagues  as per their systematic review of the peer-reviewed research looking at quality of life for adults on the autism spectrum and how said quality of life (QoL) is measured. Covering a topic that has received some significant airtime on this blog (see here), authors noted the available literature is generally consistent with the notion that for quite a few people, a diagnosis of autism or autism spectrum disorder (ASD) brings significant challenges that impact on how one feels/interprets their life experience. I know not everyone will necessarily agree with such sentiments but that is what the available science literature suggests (see here also).
The associated finding that there are currently "no comprehensive autism spectrum disorder-specific quality of life measurement tools validated for use with representative samples of adults on the autism spectrum" is also an important one. My first thought was that such a 'gap' might be partially plugged as and when the ICF core sets for autism are finally agreed upon (see here and see here for more information) and put into practice. More than that however, I hark back to my previous mega-post on QoL and autism and the idea that QoL is often a very subjective thing and indeed, is a dynamic concept, that can readily change as a function of nature and nurture. Any such measurement tools need to keep this in mind alongside how facets of autism and important comorbidities can wax and wane as a function of maturation for example and how said changes might impact on QoL (see here). They also need to bear in mind that proxy reporting when required, may not be the most accurate way of reporting .
The bottom line however is that QoL is affected by a diagnosis of autism, either directly or indirectly. I might add that, minus any sweeping generalisations or 'blame', QoL issues in the context of autism are also not confined to the person but potentially also significant others (see here). The next [complicated] question being: what can be done to improve QoL in the context of autism?  (ensuring that all aspects of the autism spectrum are included in that question) and keeping in mind that 'a good outcome' might mean different things to different people  as it might with other age-groups .
 Ayres M. et al. A systematic review of quality of life of adults on the autism spectrum. Autism. 2017 Aug 1:1362361317714988.
 Flynn S. et al. Measurement tools for mental health problems and mental well-being in people with severe or profound intellectual disabilities: A systematic review. Clin Psychol Rev. 2017 Aug 11;57:32-44.
 Hwang YIJ. et al. Aging well on the autism spectrum: the perspectives of autistic adults and carers. Int Psychogeriatr. 2017 Aug 11:1-14.
 Lounds Taylor J. When is a good outcome actually good? Autism. 2017 Aug 1:1362361317728821.
 McConachie H. et al. Parents Suggest Which Indicators of Progress and Outcomes Should be Measured in Young Children with Autism Spectrum Disorder. J Autism Dev Disord. 2017. Aug 31.