Abstract
Young adults increasingly use AI to seek support and manage their feelings. Understanding when and where they use AI for emotion regulation (ER) and its effectiveness can provide evidence needed for research, practice, and policy. In a 13-day ecological momentary assessment study, 3,048 Chinese university students reported emotional situations, ER strategies, and affect four times daily. AI use for confiding, advice, or emotional support was reported on 2.0% of 134,275 prompts and by 17.3% of participants at least once. In person-level logistic regression, use was concentrated among students with greater lifetime AI use (OR up to 3.12); in multilevel logistic regression, it was more likely during digital, academic, and interpersonal situations (OR 1.22-2.56). AI use did not predict next-prompt affect overall, but was followed by lower positive affect when neither stressors nor positive events had occurred, weakening as more events co-occurred. AI has entered everyday ER as a context-dependent resource.