title: Dissociation between objective psychomotor impairment and subjective sleepiness after diazepam administration in the aged people.
abstract: The aim of the present study was to clarify whether subjective sleepiness accurately reflects benzodiazepine-related decline in psychomotor function after taking benzodiazepines (BZPs) in aged people. Subjects were eight healthy, young (mean age, 19.8 years) and seven healthy, older (mean age, 60.9 years) men. Placebo and diazepam (DZP) were administered orally in a single-blind crossover manner to the young subjects (placebo, 5 mg DZP and 10 mg DZP) and to the older subjects (placebo and 5 mg DZP). Plasma drug concentration, choice reaction time (CRT) as an objective measure of psychomotor function, and the Stanford Sleepiness Scale (SSS) as a measure of subjective sleepiness were monitored every 20 min from 1000 until 1600 h, being the drug administered at 1200 h. Pharmacokinetic variables did not differ significantly between the two age groups. DZP at 10 mg in young subjects induced significant increases in both the CRT and SSS score. DZP at 5 mg induced no significant increase in SSS score in either age group but did induce a significant increase in CRT only in the older subjects that matched that in young subjects given 10 mg DZP. The older subjects suffered from dissociation between subjective sleepiness and objective psychomotor impairment under DZP treatment. Such individuals may underestimate the detrimental effects on brain function.
authors.affiliation: Division of Neuropsychiatry, Department of Neuro and Locomotor Science, Akita University School of Medicine, Akita, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Echizenya
authors.forename: Kazuo
authors.initials: K
authors.lastname: Mishima
authors.forename: Kohtoku
authors.initials: K
authors.lastname: Satoh
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kusanagi
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ohkubo
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging; D000704:Analysis of Variance; D001288:Attention / Q000187:drug effects; D002492:Central Nervous System Depressants / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D018592:Cross-Over Studies; D003975:Diazepam / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance / Q000187:drug effects* / Q000502:physiology; D016037:Single-Blind Method; D012890:Sleep / Q000187:drug effects* / Q000502:physiology
chemical_list: D002492:Central Nervous System Depressants; D003975:Diazepam