The contributions of mentalizing and impulsivity dimensions to the clinical expressions of Attention-Deficit Hyperactivity Disorder during adulthood

• Identifying the relationship between psychological processes can inform more on ADHD. • Several impulsivity facets are related to symptoms, clinical severity and quality of life. • Self-mentalizing contributed to self-rated symptoms, clinical severity and quality of life. The aim of our study is to characterize how transdiagnostic dimensions of personality trait impulsivity and mentalizing can be related to clinical domains and functional impairments in adults with ADHD. We specifically explore their relationship to 3 levels of expression of psychopathology: number of diagnostic symptoms (1), additional clinical indicators of severity (2), general social functioning (3). We included 157 outpatients with ADHD aged to 16 to 77 consulting in a specialized psychiatric center in an University Hospital. Diagnostic procedure was based on the ACE+ and the ASRS. Mentalizing was assessed with the Mentalization Scale and impulsivity was evaluated with the UPPS-P Short Form. Several forward stepwise linear and logistic regressions were performed. Our results show that independently of gender and age effects, impulsivity facets of personality and especially urgence dimensions are significantly related to ADHD symptoms, clinical severity and quality of life. We also found that mentalizing dimensions, and most prominently self-mentalizing, further contributed to self-rated ADHD symptoms, clinical severity (suicidal history in particular) and quality of life. These results suggest that an evaluation of impulsivity and mentalizing dimensions may be worthwhile to enrich evaluation, personalize diagnosis, case formulation, psychoeducation strategies and treatment for adults receiving the diagnosis of ADHD.