Fig. 1

Schematic of study protocol. Participants were enrolled after providing informed consent and completed the Depression, Anxiety, and Stress Scale-21 (DASS-21) and Patient Health Questionnaire-9 (PH9). To avoid sequence effects, they were randomly allocated to one of three screen condition orders (computer generated), each consisting of six 3-min exposures (1-min between conditions): TV (orange), Gaming (G, blue), and Social Media (SM, green). Two exemplars were included per condition to ensure effects reflected broader screen use patterns rather than the specific stimuli. Functional near-infrared spectroscopy (fNIRS) electrodes were placed over the dorsolateral prefrontal cortex (dlPFC) at F3 and F4 (EEG 10/20 system) for continuous brain activity measurement. Visual analogue scales (VAS) were administered after each condition to assess mood changes.