Background: Studies conducted in different countries have reported a relationship between suicidal tendencies and childhood trauma experiences, personality traits, and psychological pain. It would be valuable to re-examine such a relationship in Iranian culture. Objectives: This study aimed to investigate early life experiences, temperament, character, and psychological pain in suicidal attempters and normal individuals. Methods: This cross-sectional, causal-comparative, basic research was conducted retrospectively on all individuals who had attempted suicide by drug poisoning and were referred to Imam Khomeini Hospital of Kermanshah, Iran. The study sample, consisting of 121 suicide attempters by drug poisoning and 121 healthy individuals (companions of suicide attempters), was selected by purposeful sampling, according to the inclusion and exclusion criteria. The participants completed the questionnaires about early life experiences, temperament, character, and mental pain. A discriminant analysis was also performed to analyze the data. Data analysis was performed in SPSS version 26. Results: Based on the simultaneous discriminant analysis, 4 predicting variables (early life experiences, temperament, character, and psychological pain components) could explain 91.7% of the variance in suicide attempts. Based on the stepwise discriminant analysis, six subscales predicting variables (emptiness/worthlessness, harm avoidance, persistence, worthlessness, cooperation, and self-transcendence) could explain 91.7% of the variance in suicide attempts, as shown in the discriminant function analysis for differentiation of suicide attempters from normal people. Conclusions: Based on the findings of the present study, emptiness/worthlessness, personality traits, and early traumatic experiences can predispose individuals to suicide attempts. Therefore, there is an urgent need for psychological interventions to reduce psychological harm in suicidal attempters.