BackgroundThe recent outbreak of COVID-19 has impacted adversely upon the mental health of millions of people worldwide. Impacts on the mental health conditions and the associated predictors relating to adults in Pakistan, the fifth most populous country in the world, during the COVID-19 remain understudied. Our aim was to investigate distress, anxiety, and overall mental health and their associated predictors among Pakistani adults in this pandemic. We specifically examine mental health issues based on the distance from the epicenter, (a predictor that has revealed opposing evidence in other countries) based on the theories of typhoon eye effect and ripple effect. The sample consisted of 601 adults who were surveyed online about 2.5 months into the outbreak across Pakistan with varying distances from the epicenter of COVID-19 of Karachi.ResultsThe results showed that 9.2 and 19.0% of the participants surpassed the cut-off criteria for distress and anxiety disorders, respectively. Overall, the distance from the epicenter positively predicted the mental health of adults in Pakistan, and family size negatively moderated this effect. The distance from the epicenter negatively predicted distress and anxiety disorders for adults in large families, which are quite common in Pakistan.ConclusionThe evidence of the study interestingly finds that the prediction of the mental health of people by their distance from the epicenter depends on family size. The evidence of this study can help to provide initial indicators for mental health care providers to screen vulnerable groups in Pakistan, a populous country that continues struggling to cope with the COVID-19 pandemic.