Abstract
Smartphones have become the "backbone" of the connected society, reshaping social interactions in a period of adolescence marked by a neuropsychology vulnerability that is sensitive to intensive technological mediation. This study analyzes the relationship between problematic mobile phone use and the social and assertiveness skills of adolescents. Through a cross-sectional design, the answers of 1864 adolescents aged between 11 and 21 years old from education centers located in Cordoba (Spain) were analyzed, through a questionnaire that collected sociodemographic variables, the MPPUSA scale, to measure the inadequate use of mobile phones, and the ADCA-1 to assess social skills and assertiveness. The results revealed inadequate levels of mobile phone use and low levels of social skills, with nomophobia and negative consequences emerging as the dimensions most related to these outcomes. A decision tree analysis identified negative consequences as the variable with the strongest association with the level of social development. The findings point to a concerning situation in which not only the usage time but also quality of use are associated with the psychosocial development of this population group. Therefore, preventive and educational interventions addressing digital literacy, management of emotions, and the promotion of face-to-face social skills are necessary.