On the path to psychiatric care, many patients who experience their first episode of mental disorder consult general practitioners or physicians of general hospitals before consulting psychiatrists. Some patients receive proper care promptly while others experience a delay in treatment. We investigated treatments and psycho-education given to patients by general practitioners or physicians of general hospitals, particularly focusing on informed diagnosis. We conducted a multi-center collaborative study in Japan. In this study, 15 facilities participated, including 4 university hospitals, 3 general hospitals, and 8 psychiatric hospitals. A total of 382 patients experiencing their first episode of mental disorder were enrolled. Among them, 157 patients primarily consulted general practitioners or general hospitals. We divided the 157 patients into 3 groups according to the kind of psycho-education given by general practitioners or physicians of general hospitals: those who were told nothing about their diagnosis nor mental condition (N = 74, 47.1%), those who were not given a direct diagnosis but were informed about their condition in some way (N = 55, 35.0%), and those who were directly informed of their diagnosis (N = 28, 17.8%). We found that almost half of the patients were told nothing about their diagnosis nor mental condition by general practitioners or physicians of general hospitals. Patients who were likely to be directly informed of their diagnosis were those who were recommended to see a doctor by someone, or those with a lower global psychosocial function. The patients who were told nothing about their diagnosis nor mental condition were mainly covered by national health insurance, and had decided to go to hospitals or clinics under their own volition. Sorted by ICD-10 F code, patients diagnosed as F0, F3, or F4 accounted for 89.9% of all subjects. We compared treatment delays among these 3 categories. The median treatment delay in patients diagnosed correctly as F0 by general practitioners or physicians of general hospitals was 50 weeks, that in patients diagnosed as F3 was 4 weeks, and that in patients diagnosed as F4 was 5 weeks. These findings suggest that patients might be treated in different ways according to their diagnosis by general practitioners or physicians in general hospitals. Our results suggest the importance of further educating general practitioners and physicians of general hospitals about mental disorders, in order to not only shorten the duration of untreated psychosis, but also for patients to be given proper primary care.