Objective: To analyze the psychological phenotype of ADHD, and the effect of ADHD on life satisfaction and personality in adults with neurofibromatosis type 1 (NF1). Method: Adults with NF1 without (n = 26) and with ADHD (n = 22), and adults with ADHD only (n = 27) completed questionnaires on personality traits and life satisfaction. Differences between groups were analyzed. Results: Participants with NF1 and ADHD present an emotionally instable psychological phenotype similar to adults with ADHD only, which differed significantly from that in adults with NF1 only. Participants with NF1 and ADHD had significantly lower overall life satisfaction than NF1 participants without such symptoms, affecting general health, self-satisfaction, sexuality, and family. Conclusion: The authors’ findings show that ADHD symptoms can persist through adulthood. These NF1 patients display problems similar to those of adults with ADHD only. This finding is highly relevant to understand the behavioral and psychological phenotype in adults with NF1 and to offer psychological and/or medical treatment. (J. of Att. Dis. 2012; XX(X) 1-XX)