Fig. 1

A Normalized importance of independent variables in predicting caseness. B Classification tree produced by CART analysis using Gini criterion. Node 0 contains frequency counts and percentages of all observations in the model on the dependent variable, IES-6. Nodes 1–14 display the number and percentage of participants in that subgroup and the percentage of accurate classification of caseness by that subgroup. Dependent variable: Impact of Event Scale (IES-6). Independent variables: Life threat, Fear, Helpless, Horror, Sadness and grief, Worried about the safety of others, Frustrated or angry, Worry loved ones getting COVID-19, Worry significant others getting COVID-19, Losing control over emotions, Difficulty of being confined, Country, Physical reactions (e.g. sweating, shaking), Gender, Seek and share information mass media, Guilt, Know anyone with the COVID-19, Ashamed of my emotional reactions, Occupation, Difficulty of being quarantined, Connection to and support social media, Age, Ethnicity, Number of children, Level of education, Pregnancy status, Separated from loved ones, Socially isolated, Professional emotional help & support, Quarantined, Family emotional help & support, Friend emotional help & support, Experienced COVID-19 symptoms, Felt I might pass out, Exposed to infected individuals or objects as part of work, Difficulty controlling bowel and bladder, Received financial support, Experienced material hardship, Tested for the COVID-19, Travel in or out of your home country, Significant other experienced COVID-19 symptoms, Lost loved ones, Lost your job, At-risk group for the COVID-19, Diagnosed with the COVID-19, Marital status, Received medical care for COVID-19, Hospitalized for COVID-19, Significant other diagnosed with the COVID-19, Been at ICU for COVID-19