A FURTHER EXAMINATION OF THE TIME-DEPENDENT EFFECTS OF OXAZEPAM AND LORAZEPAM ON IMPLICIT AND EXPLICIT MEMORY

Until recently, research indicated that all benzodiazepines impair exp licit memory, while only lorazepam impairs priming. Stewart and associ ates provided preliminary data which indicated that both oxazepam and lorazepam may impair implicit memory: but in a time-dependent fashion. The present study was designed to replicate Stewart et al.'s findings after overcoming several limitations of the original study. Thirty su bjects were administered an acute dose of lorazepam (2 mg), oxazepam ( 30 mg) or a placebo and were tested with an implicit (word-stem comple tion) test and an explicit (cued recall) test. However, subjects were only tested at 170 min postdrug (close to oxazepam's theoretical peak concentration) to rule out the possible ''explicit memory contaminatio n'' explanation of the Stewart et al. implicit memory findings. Consis tent with previous research, both drugs impaired explicit memory relat ive to placebo. Also, both lorazepam and oxazepam impaired priming per formance, supporting the ''time-dependence'' interpretation of the Ste wart et al. findings. The results also indicate that episodic memory i s impaired by both benzodiazepines in a lime-dependent fashion even wh en the research methodology used involves everyday memory demands.