The aim of this study is to provide a survey of systematic reviews that have evaluated the effects of psychosocial interventions for adult people with intellectual disabilities and/or an autistic syndrome with concurrent mental health problems. Reviews for inclusion were identified through searches of 10 electronic databases. The authors found that 3 out of 126 published reviews met the inclusion criteria for interventions, population, and being considered a systematic review. The results imply a weak scientific support for behavioral therapy, cognitive-behavioral therapy, and some forms of integrated care and support. However, the primary studies included in the reviews have several methodological shortcomings. The results suggest future research initiatives in the direction of more effectiveness studies of good quality and reproduction of high-quality systematic reviews.