Purpose of review: Research has indicated that loot boxes are risky gaming components that could exacerbate Internet gaming disorder due to a link between loot box purchasing and gambling. We conducted a systematic review to identify the characteristics of people who purchase loot boxes with real money, focusing on the relationships (a) between loot boxes and gaming, (b) between loot boxes and gambling, and (c) between loot boxes and other variables.

Recent findings: Of the 201 studies examined for eligibility, we reviewed 20 studies that met the predefined criteria, which were extracted by searching electronic databases (PsycINFO, PubMed, Ovid, EBSCO, and Web of Science) and the reference lists of included studies, and that were published up to March 27, 2021. Overall, this review identified positive relationships among Internet gaming disorder-related symptoms, disordered gambling symptoms, and engagement with, or investment in, loot boxes. In addition to gaming and gambling, the relationships among some variables, such as mood, gender, physiological state, motivation, and loot box engagement, were examined.

Summary: The present review clarified relationships between loot box engagement, gaming, gambling, and other variables, such as mood, gender, physiological state, and motivation, and partially identified the characteristics of people who purchase loot boxes using real money. Specifically, those who spend more money in-game on loot boxes exhibit Internet gaming-related and/or disordered gambling symptoms and behaviors. Finally, we discussed future directions for clinical psychological studies on loot boxes.