Background: Short versions of problematic internet use (PIU) questionnaires may provide a convenient and effective way of assessing internet-related problems in various contexts, ranging from research to clinical practice. The aim of this study was to investigate whether single yes/no question (Q-single) regarding ?functional impairment due to PIU" could serve as a screening tool to indicate the potential absence of PIU, given the lack of functional impairment. Methods: Data from two online studies (N 5 524 and N 5 272) assessing internet-related behaviors among students were used for the analyses. Participants completed questionnaires (the nine-item Problematic Internet Use Questionnaire [PIUQ-9], the Compulsive Internet Use Scale [CIUS], the nine-item Patient Health Questionnaire, depression module [PHQ-9], the seven-item Generalized Anxiety Disorder scale [GAD-7]), questions about their internet use time, besides answering the QSingle question. Block-wise multiple linear regression analyses were used to determine the predictive effect of the Q-Single on PIU (as measured with the PIUQ-9 and the CIUS) and its association with depression and anxiety symptom scores (as measured with the PHQ-9 and the GAD-7). Results: The Q-Single demonstrated a high negative predictive value in screening the absence of PIU, however positive predictive value was low to moderate. Q-Single proved to be a good predictor of PIU (â 5 0.484, p < 0.001 [PIUQ-9] and â 5 0.481, p < 0.001 [CIUS]) when controlling for age, gender, and internet use time. Adjusting for the same controlling variables, the Q-Single had a moderate association with depression symptoms (â 5 0.385, p < 0.001 [PHQ-9]) and anxiety symptoms (â 5 0.252, p < 0.001) [GAD-7]) supporting the validity of the single-question instrument. Conclusions: The finding that a single question could predict absence of PIU in students, implies that functional impairment is an important indicator of PIU.  Kulcsszavak: Q-single, internet addiction, psychological correlates, assessment, questionnaire, behavioral addictions, anxiety, depression, problematic internet use