The American Psychiatric Association recently included Internet gaming disorder (IGD) as a potential diagnosis, recommending that further study be conducted to help illuminate it more clearly. This paper is a summary of the review undertaken by the IGD Working Group as part of the 2015 National Academy of Sciences Sackler Colloquium on Digital Media and Developing Minds. By using measures based on or similar to the IGD definition, we found that prevalence rates range between ∼1% and 9%, depending on age, country, and other sample characteristics. The etiology of IGD is not well-understood at this time, although it appears that impulsiveness and high amounts of time gaming may be risk factors. Estimates for the length of time the disorder can last vary widely, but it is unclear why. Although the authors of several studies have demonstrated that IGD can be treated, no randomized controlled trials have yet been published, making any definitive statements about treatment impossible. IGD does, therefore, appear to be an area in which additional research is clearly needed. We discuss several of the critical questions that future research should address and provide recommendations for clinicians, policy makers, and educators on the basis of what we know at this time.

Despite recent growth of research on prosocial media effects (e.g., Greitemeyer, 2011a & b), processes underlying these effects are not well understood. Two studies explored theoretically relevant mediators and moderators of prosocial media effects on helping. Study 1 examined associations among prosocial and violent media use, empathy, and helping with participants from 7 countries. Prosocial media use was positively associated with helping. This effect was mediated by empathy and was similar across cultures. Study 2 explored longitudinal relations among prosocial video game use, violent video game use, empathy, and helping in a large sample of Singaporean children and adolescents measured three times across two years. Path analyses yielded significant longitudinal effects of prosocial and violent video game use on prosocial behavior through empathy. Latent growth curve modeling revealed significant mediated effects of change in video game use on change in helping through change in empathy over the two-year period.

Few studies have empirically examined how media stereotypes of Muslims influence Americans' support for public policies exclusively harming Muslims. Across three studies, we tested the short-term and long-term effects of news portraying Muslims as terrorists on Americans' support for public policies harming Muslims domestically and internationally.

IMPORTANCEAlthough several longitudinal studies have demonstrated an effect of violent video game play on later aggressive behavior, little is known about the psychological mediators and moderators of the effect. OBJECTIVE To determine whether cognitive and/or emotional variables mediate the effect of violent video game play on aggression and whether the effect is moderated by age, sex, prior aggressiveness, or parental monitoring. DESIGN, SETTING, AND PARTICIPANTSThree-year longitudinal panel study. A total of 3034 children and adolescents from 6 primary and 6 secondary schools in Singapore (73% male) were surveyed annually. Children were eligible for inclusion if they attended one of the 12 selected schools, 3 of which were boys' schools. At the beginning of the study, participants were in third, fourth, seventh, and eighth grades, with a mean (SD) age of 11.2 (2.1) years (range, 8-17 years). Study participation was 99% in year 1. MAIN OUTCOMES AND MEASURESThe final outcome measure was aggressive behavior, with aggressive cognitions (normative beliefs about aggression, hostile attribution bias, aggressive fantasizing) and empathy as potential mediators. RESULTSLongitudinal latent growth curve modeling demonstrated that the effects of violent video game play are mediated primarily by aggressive cognitions. This effect is not moderated by sex, prior aggressiveness, or parental monitoring and is only slightly moderated by age, as younger children had a larger increase in initial aggressive cognition related to initial violent game play at the beginning of the study than older children. Model fit was excellent for all models.CONCLUSIONS AND RELEVANCE Given that more than 90% of youths play video games, understanding the psychological mechanisms by which they can influence behaviors is important for parents and pediatricians and for designing interventions to enhance or mitigate the effects. EmpathyThe 16-item Children's Empathic Attitudes Questionnaire 7 (coefficient α = 0.86) was used, modified for language appropriate to the culture (eg, "When I see a student who is upset, it really bothers me"). Students responded yes, maybe, or no for each statement.

Cultural generality versus specificity of media violence effects on aggression was examined in seven countries (Australia, China, Croatia, Germany, Japan, Romania, the United States). Participants reported aggressive behaviors, media use habits, and several other known risk and protective factors for aggression. Across nations, exposure to violent screen media was positively associated with aggression. This effect was partially mediated by aggressive cognitions and empathy. The media violence effect on aggression remained significant even after statistically controlling a number of relevant risk and protective factors (e.g., abusive parenting, peer delinquency), and was similar in magnitude to effects of other risk factors. In support of the cumulative risk model, joint effects of different risk factors on aggressive behavior in each culture were larger than effects of any individual risk factor.