Background. Recommendations for promoting mental health during the COVID-19 pandemic include maintaining social contact, through virtual rather than physical contact, moderating substance/alcohol use, and limiting news and media exposure. We seek to understand if these pandemic-related behaviors impact subsequent mental health. Methods. Daily on-line survey data were collected on adults during May/June 2020. Measures were of daily physical and virtual (on-line) contact with others; substance and media use; and indices of psychological striving, struggling and COVID-related worry. Using random-intercept cross-lagged panel analysis, dynamic within-person cross-lagged effects were separated from more static individual differences. Results. 1148 participants completed daily surveys (657 [57.2%] females, 484 [42.1%] males; mean age 40.6 [SD 12.4] years). Daily increases in news consumed increased COVID-related worrying the next day (cross-lagged estimate=0.034 [95% CI 0.018 to 0.049], FDR adjusted p=0.00005) and vice versa (0.03 [0.012 to 0.048], FDR-adjusted p=0.0017). Increased media consumption also exacerbated subsequent psychological struggling (0.064 [0.03 to 0.098], FDRadjusted p=0.0005). There were no significant cross-lagged effects of daily changes in social distancing or virtual contact on later mental health.Conclusions. We delineate a cycle wherein daily increase in media consumption results in a subsequent increase in COVID-related worries, which in turn increases daily media consumption. Moreover, the adverse impact of news extended to broader measures of