Hyperfocus can be defined as a state of intense selective attention on an engaging activity. During this cognitive state, time is distorted by the decreased perception of unrelated stimuli in the environment (Ashinoff & Abu-Akel, 2021). This state of mind is more known in the domain of sports but not necessarily with screen devices. With the increase of the latter, many studies have observed that anxious and depressive individuals have shown to have an increase in their screentime (Hamer, Stamatakis, & Mishra, 2010; Lee Smith & al., 2020). According to research, negative metacognitive beliefs seem to play an important role in anxiety and depressive symptoms (Wells, 2009) and they seem to have an influence on the access to hyperfocus (Love, Kannis-Dymand, & Lovell, 2019). Knowing this, we assumed that there was an increase of hyperfocus on screens with anxious and depressive people. And based on the mediation theory of Baron and Kenny (1986), we were able to hypothesize that the relation between having anxiety and depressive symptoms and hyperfocus screentime would be mediated by negative metacognitive beliefs. Through a course credit at the University of Geneva and our acquaintances, our sample for this study included 101 adults aged 20 to 49 years old (M = 27,60, SD = 7,12). The results corroborated with our hypothesis. A higher score of anxiety and depressive symptoms was related to a higher frequency of hyperfocus on screens. We could confirm then through mediation analysis that negative metacognitive beliefs played a role of a complete mediator in the relationship between the score of anxiety and depressive symptoms and the frequency of hyperfocus on screens. The findings indicate that the relation between the score of anxiety and depression and the frequency of hyperfocus on screens exist through the presence of negative metacognitive beliefs.