Current clinical trials of cognitive enhancers in Japan

The primary purpose of this paper is to review the clinicopharmacological properties of brain metabolism enhancers available in Japan. The major target symptoms of brain metabolism enhancers are peripheral psychiatric symptoms (symptoms of the noncognitive type) of demented patients. A review of double-blind studies of major brain metabolism enhancers in Japan revealed that 60-70% of patients were better than slightly improved and 20-30% better than moderately improved in treatment of cerebrovascular disorders. In treatment of Alzheimer-type dementia, on the other hand, the better than slightly improved patients comprised 30-70% in mild to moderately demented cases. Severe cases of dementia showed a lower improvement rate. The incidence of side effects ranged from 4-9%. In our geriatric outpatient clinic, 72.5% of elderly demented patients (85% were mild-moderate dementia) exhibited better than a moderate improvement with combined psychopharmacotherapy, so far as peripheral psychiatric symptoms were concerned. Psychophysiological analysis of cases in terms of improvement of scores on Hasegawa's dementia scale strongly suggested that sporadic cases with cognitive improvement were brought about, at least secondary to improved vigilance, or with improved concentration and attention.