Two hundred and one school refusers (< or =18 years old), excluding schizophrenia, were treated at the Department of Neuropsychiatry, Hirosaki University Hospital between April 1975 and March 1995. Of 56 cases of school refusal, 31 did not improve for more than 2 years (group P), and 25 cases had improved in the degree of school refusal and social impairment (group B). The remaining cases were excluded from the analysis for several reasons. There was no significant difference between groups B and P in age at the first psychiatric evaluation as well as the age of onset of school refusal. The duration from school absence to the first evaluation of group P was significantly longer than that of group B. The duration of school refusal significantly and positively correlated with the duration from school absence to the first evaluation. Introversion and nervousness prolonged the duration of school refusal. The non-presence of volition for school attendance, and a low frequency of school attendance during the 1 month prior to the first evaluation influenced the prolongation of school refusal. The 'duration from school absence to the first evaluation', the 'patient's character', the 'non-presence of volition for school attendance' and the 'frequency of school attendance' influenced the prolongation of school refusal. The introduction of treatment within 10 months of the onset of school refusal is an important factor in preventing the prolongation of the school refusal.