ObjectiveTo investigate the condom use of men who have sex with men （MSM） in Shanghai， the information motivation behavioral skills model （IMB） theory was used to introduce psychosocial factors and study the relevant factors of consistent condom use （CCU） in this population. MethodsA cross-sectional study of 547 MSM in four districts of Shanghai was conducted by snowball sampling. The structural equation model based on psychosocial optimization was constructed and validated using the data collected by structured questionnaires. ResultsAmong the 547 respondents， the proportion of CCU in the past six months was 45.5%. Comparing the fitness of the initial model with that of the adjusted model， we found that the fitness of the adjusted model was good. ConclusionThe proportion of CCU among MSM in Shanghai is relatively low； In addition， information and motivation do not directly affect the CCU of this population； Only behavioral skills have a direct effect on CCU. Finally， social psychological measures should be emphasized for this population， and comprehensive and multi-level strategies should be formulated to control the spread of HIV in this population.

ObjectiveTo explore the relationships between internet gaming disorder (IGD), interpersonal needs, loneliness, and depression in adolescents through the construction of a chain mediation model, to clarify the underlying mechanisms of these associations, and to provid a theoretical basis for depression prevention and intervention. MethodsBased on the data of the 7th Population Census, using convenient sampling method 1 106 adolescents aged between 10‒19 years in South China (176), North China (147), Central China (332), and East China (451) were selected to conduct a cross-sectional survey, with a ratio of 1∶1∶1.5∶2.5. The survey was conducted with a questionnaire consisting of general information (sex, age, grade, parents’ education level), the Chinese version of the IGDS9-SF, the INQ-15, the short-form of the ULS-8 and the PHQ-9 were used to evaluate the depression status of adolescents. Spearman correlation analysis was used to explore the correlation between the variables. A multiple-mediator model was constructed using IBM SPSS Statistics 22.0 PROCESS to examine the mediating effects of interpersonal needs and loneliness on the relationship between IGD and depression. The significance of the chain mediating effect was tested using the Bootstrap method. ResultsOverall, 39.06% (432/1 106) adolescents experienced depression. The incidence of depression among adolescents with smoking and without smoking was 62.50% and 38.36%, respectively. Similarly, the incidence of depression among adolescents with alcohol consuming and without alcohol consuming was 61.94% and 35.94%, respectively. There were statistically significant differences between IGD, interpersonal needs, loneliness, and depression (P<0.01). The chain mediation model demonstrated a good fit, and the bootstrap test showed that the 95%CI of each mediation path did not include 0, indicating significant mediation effects. The overall effect was 0.337. The direct effect of IGD on depression was significant (effect value=0.138, 95%CI:0.102-0.173, P<0.001). The mediation effects included three paths: ① IGD →interpersonal needs → depression (effect value=0.073, P<0.05), accounting for 21.47% of the total effect;② IGD→ loneliness → depression (effect value=0.093, P<0.05), accounting for 27.35%; and ③ IGD → interpersonal needs → loneliness → depression (effect value=0.036, P<0.05), accounting for 10.59%. ConclusionInterpersonal needs and loneliness independently and jointly mediate the relationship between IGD and depression among adolescents. To reduce depression and improve mental health in this population, measures should be taken to prevent and intervene in IGD, address adolescents’ social and emotional needs, enhance satisfaction of interpersonal needs, and reduce loneliness.