SURVIVAL ANALYTIC APPROACH TO LONG-TERM PRESCRIPTION OF BENZODIAZEPINE HYPNOTICS

Eight hundred and sixty-two patients who visited the department of neu ropsychiatry and who were prescribed benzodiazepine (BZ) hypnotics wer e investigated to evaluate the actual state of their use, in terms of age, gender, diagnostic categories according to ICD-9, duration of pre scription and dose equivalent to diazepam prescribed. The frequency of prescriptions in subjects were surveyed using Kaplan-Meier survival a nalysis at every 3 months. Mean survival time to discontinuation was 8 .5 months. A total of 60% of the subjects did not receive BZ hypnotics at the end of the third month, but 20% remained to be prescribed afte r 1 year. Moreover, 7.9% of the subjects were prescribed BZ hypnotics even after 3 years. The results indicated that 20% of patients who had started prescriptions for BZ hypnotics had the potential to induce de pendence. The following variables were found in the long-term prescrip tion: male patients; aged patients over 60; and affective psychoses (w hich mainly consisted of depression) including neurotic depression, in the present study. A low dose was considered to be associated with an ability to be free from BZ hypnotics in an early period.