Definitions and scores
Previous studies have demonstrated that the SCL-90-R tests have good internal consistency, reliability, and validity (Li et al., 2015). Overall mental health status was evaluated via 3 global scales: 1. The Global Severity Index (GSI), indicating a global scale; 2. Positive Symptom Total (PST), expressing all items more than 1 point to display number of items did the subjects presenting symptoms; and 3. Positive Symptom Distress Index (PSDI), meaning the sum of values of none-zero items by PST, reflecting the extent of severity of items that subjects feel bad about themselves. Higher score indicated more seriously mental health status.