Perceived treatment urgency of mental disorders are important as they determine utilization of health care. The aim was to analyze variations in perceived treatment urgency in cases of psychosis (adolescents), alcoholism (adults), and depression (older adults) with two levels of severity each by characteristics of the case and the respondents. A telephone survey (N = 1200) with vignettes describing cases of psychosis, alcoholism, and depression was conducted in Hamburg, Germany. Vignettes varied by symptom severity and sex. Perceived treatment urgency was assessed by three items. A sum scale was calculated. Linear regression models were computed to analyze differences in perceived urgency by characteristics of the case (severity, sex) and the respondents (sex, age, education, migration background, illness recognition, personal affliction). Perceived treatment urgency was significantly higher in severe cases and varied by education. Additionally, regarding psychosis, estimated urgency varied significantly by correct illness recognition. With regard to depression, perceived urgency differed significantly by age and correct illness recognition. Interaction effects between case severity and sociodemographic characteristics of the respondents, personal affliction, and correct recognition of the disorder were found. The identified differences should be considered in the development of interventions on mental health literacy with regard to adequate urgency assessment.