<p>Problematic short-form video users (PSVU) usually exhibit deficits in inhibitory control, which has been attributed to an imbalance between the goal-directed and habitual systems. However, the cognitive processes underlying this association remain unclear. From an information-processing perspective, this study employed the drift–diffusion model (DDM) to examine the link between inhibitory control deficits and a dual-system imbalance in PSVU. Thirty PSVU and twenty-eight matched controls completed a go/no-go task and a contingency degradation task. DDM was applied to model latent information-processing mechanisms from go/no-go performance. Habitual tendencies were assessed using ratio scores across contingency degradation conditions. Compared with healthy counterparts, PSVU showed a higher false-alarm rate and lower boundary separation in the go/no-go task. No significant group differences were found in other DDM parameters. In the contingency degradation task, PSVU showed a stubborn ratio score during action-outcome congruence transitions, which correlated positively with the boundary separation index. These findings suggest that, rather than abnormal information accumulation processes or response bias, inhibitory control deficits in PSVU arise from a more impulsive decision-making pattern, associated with insensitivity to task-setting changes. The study provided novel implications for intervention in behavioral addictions.</p>