Can likes returned by peers within a day improve users’ depressive/manic levels in a massive multiplayer online game? A randomized controlled trial

Associations exist between avatars’ behaviors in massive multiplayer online games (MMOGs) and their users’ depressive/manic levels; however, these causal relationships remain unclear. Therefore, we designed a parallel-group superiority trial to examine the causal effects of an avatar’s “likes” on its user’s depressive/manic levels. In total, 416 users of Pigg Party, a popular MMOG in Japan, were recruited and randomly assigned to the morning, evening, all-day, and waitlist groups. The morning and evening groups were asked to send likes to their peers at least five times during a specific period (7:00 AM to 8:00 AM and 7:00 PM to 8:00 PM, respectively) for four weeks, and the all-day group was asked to send likes anytime during the day (12:00 AM to 11:59 PM). The waitlist group did not receive any interventions. Depression and manic levels were measured before and after the intervention using self-reported questionnaires. In the all-day group, after sending a like to a peer, the frequency of receiving a like back from that peer was slightly higher, and its frequency was significantly negatively correlated with the level of depression. These results suggest that the exchange of likes on the MMOG can reduce depression levels of its users.