RESUMEN
BACKGROUND: Autism spectrum disorder (ASD) in adulthood is associated with severe impairments in functioning and poor health, while ASD is also affecting close relations. Accessible first-line interventions addressing the complex clinical needs and care coordination are lacking. METHODS: This study investigated the feasibility and preliminary effects of a new psychoeducational intervention (Prisma) developed for intellectually able adults with ASD and their close relations in an outpatient setting. The manualized Prisma intervention consist of four weekly group sessions guided by trained group leaders and providing information about autism, support, and services. Feasibility was examined through treatment completion rate and group-level comparisons between intervention completers and non-completers (Student's t-test, Fisher's exact test, and Pearson's chi-squared test). Perceived treatment credibility was investigated by within-group comparisons of participant's self-ratings from pre-intervention to post-intervention, as well as by group leaders' ratings using an adjusted questionnaire. Treatment satisfaction was examined quantitatively regarding the session evaluations (Student's t-tests), as well as by a qualitative thematic analysis of participants' feedback. Preliminary efficacy was studied using paired t-tests (pre- and post-intervention). RESULTS: Completion rate was 77% (n = 71 of the 92 adults with ASD) and 73% (n = 69 of the 94 close relations), respectively. Participants considered Prisma to be an acceptable intervention indicated by increases in treatment credibility and expectations from pre- to post-intervention. The group leaders reported treatment credibility in the same range as the participants. Both autistic adults and their close relations reported good treatment satisfaction for each session, while the qualitative thematic analysis indicated that Prisma could be improved by enhancing active participation. This participant feedback will be used to further improve the intervention for an upcoming RCT. Preliminary analyses of effects showed promising results with an increase in knowledge of ASD and some indications for improvements in relationship quality, mental health, quality of life, acceptance of diagnosis and burden of care. CONCLUSIONS: Overall, results indicate that the Prisma is a feasible and acceptable first-line intervention in outpatient services. Randomized controlled trials are needed to further corroborate the evidence base of this novel intervention. TRIAL REGISTRATION: Clinicaltrials.org NCT0446097, retrospectively registered July 8th 2020.