Benzodiazepine-induced reduction in activity mirrors decrements in cognitive and psychomotor performance.
OBJECTIVE
To assess whether actigraphy is sensitive to benzodiazepine-induced changes in cognitive and psychomotor performance and sleep.


METHODS
Healthy young volunteers (n = 23; 11 males), were randomised to a double-blind, placebo-controlled, crossover trial. Actigraphy was used to record motor activity continuously. Following dosing at 18.00 h with 2.5 mg lorazepam (LZP), psychomotor and cognitive assessments were made at hourly intervals post-dose for 4 h and after sleep at 14.5 h post-dose.


RESULTS
Activity levels were significantly reduced after LZP for 5 h post-dose (p = 0.0104), during sleep (5-13 h) (p < 0.02) and the following morning, 13-14.5 h post-dose (p < 0.02). At the same time cognitive and psychomotor performance was also significantly impaired (p < 0.05). LZP also significantly increased actigraphic sleep efficiency and sleep per cent (p < 0.02).


CONCLUSIONS
This study showed that activity levels were significantly reduced following dosing with a benzodiazepine and these changes coincided with impairment of cognitive and psychomotor performance. Actigraphy, therefore, appears to be able to reflect the psychopharmacological effects of a benzodiazepine in changes in daytime function and nocturnal behaviour, which, without waking the subject, is beyond the power of conventional psychometrics.
Dawson
Jean
J
Faculty of Health and Medical Sciences, HPRU Medical Research Centre, University of Surrey, Guildford, UK. j.dawson@surrey.ac.uk
Boyle
Julia
J
Stanley
Neil
N
Johnsen
Sigurd
S
Hindmarch
Ian
I
Skene
Debra J
DJ
D000328:Adult; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008140:Lorazepam / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009483:Neuropsychological Tests; D011594:Psychometrics; D011597:Psychomotor Performance / Q000187:drug effects*; D012890:Sleep / Q000187:drug effects; D013997:Time Factors; D055815:Young Adult
D014151:Anti-Anxiety Agents; D008140:Lorazepam