Background: Mental illness are common among medical students. Currently, there is increasingly emboldened literature around mental illness and suicide in medical students. More attention has begun to be paid about psychological screening of medical students.
Objective: To analyze whether or not the psychological test on  the first day of interview can distinguish medical students without mental illness from those with mental illness.
Materials and Methods: A retrospective study was conducted in 115 medical students of the Faculty of Medicine, Srinakharinwirot University, Thailand. The psychological tests, 16 personality factors (PF) test, emotional intelligence (EQ) test, and draw a person test were used to measure psychological well-being of case group and control group on their first day of interview. There were 23 medical students with mental illness in the case group and 92 medical students without mental illness in the control group. Chi-square and Fisher’s exact test were used to make the group comparisons.
Results: The results obtained from statistical analysis indicated that relationship was important predictor of mental illness. Most
students (56.52%) have mental illness on the fourth year. The demographic data revealed that female medical students had suffered more mental illness (1.8 times than males). On group comparisons, there was no statistically significant difference in demographic data between the case group and the control group.
Conclusion: Mental illness appears to be common in medical students and varies by gender. Interpersonal relationship is an important predictor for mental illness in Thai medical students, and therefore, needs to be more carefully adopted when conducting psychological screening. A closer attention to applying more psychological tests that measure the students’ relationship is suggested when planning to address the mental health of medical students.

Keywords: Medical students; The psychological test; Mental illness