Insistence on sameness, repetitive negative thinking and mental health in autistic and non-autistic adults.

participants were recruited from community settings. All participants completed measures of repetitive behaviours; a measure of anxiety and depression; and two measures of repetitive negative thinking (ruminating and obsessing). Autistic community participants had significantly higher repetitive behaviours, rumination and obsessing scores than non-autistic community participants. We found that higher rates of repetitive behaviours contributed to more repetitive thinking (obsessing and ruminating), which contributed to higher rates of depression and anxiety. The higher rates of repetitive negative thinking found in autistic individuals may contribute to higher rates of mental health problems in this group. Mental health assessments and interventions for autistic people should therefore consider the role of multiple forms of repetitive negative cognition and behaviour, which cut across diagnostic categories such as anxiety, depression and obsessive-compulsive disorder. These should be considered when aiming to understand why individuals develop mental health conditions and why these conditions persist.