Communicative skills in Spanish children with Autism Spectrum Disorder and children with Attention Deficit Hyperactivity Disorder. Analysis through parents' perceptions and narrative production 1. Introduction Recent studies have highlighted the diagnostic conundrum that clinicians often face when establishing differential diagnoses of verbally fluent school-age children with Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) (Grzadzinski, Dick, Lord, & Bishop, 2016). These two neurodevepmental disorders show a high co-occurrence; in fact, there is an overlap in genetic, neurobiological and neuropsychological bases, such as executive functioning or theory of mind skills (Miranda, Baixauli, Colomer y Roselló, 2013). One relevant aspect that can shed light on this complex topic is the analysis of communication. Persistent deficits in social communication are present across the autism spectrum (Schuh, Eigsti, & Mirman, 2016) and, even if they are not included in the core diagnostic criteria, language and pragmatic disturbances may often occur in ADHD (Bellani, Moretti, Perlini, & Brambilla, 2011; Green, Johnson, & Bretherton, 2014). Studies that have compared the communicative competence in ADHD and in ASD (specifically, high functioning autism, without language impairment) have mainly used the Children's Communication Checklist (CCC-2) (Bishop, 2003), designed to assess social-communicative impairments in daily interactions. Research has found similar deficits in both populations on coherence and inappropriate initiations. However, they do not seem to be as severe in ADHD as in ASD, where the impairment is more pronounced in the interpretation of the context, nonverbal communication, and stereotyped language (