A study was made of comprehensive school teachers' perceptions of mental health when it was defined as a "dynamic integration process of the physical, psychical, social, and spiritual existence of a human being." Two groups participated: 76 middle-aged teachers and 87 advanced teacher trainees. Perceptions of health and mental health were measured with attitudinal statements and with psychological, psycho-biological, and biological explanations of health etiology. Mental health and social adaptation were surveyed with thematic interviews, psychological measuring tests, and statements regarding job satisfaction. Additional information was obtained with demographic, life change, and academic achievement variables. The middle-aged teachers regarded mental health issues with more psychological understanding and emphasized more the psychological and biological etiology of health than did the teacher trainees. This was not interpreted as an effect of cultural change, but as an influence of maturation. Cultural influences played a larger part in the perception of mental health by the teacher trainees. (JD)