DRUGS AND HUMAN-MEMORY - EFFECTS OF LOW-DOSES OF NITRAZEPAM AND HYOSCINE ON RETENTION

1 The effects of diazepam (5 mg) and hyoscine hydrobromide (0.3 mg) were assessed in two memory tasks: short‐term retention of digit strings and the free recall of items from categorizable lists. 2 One hundred and two healthy subjects were tested in an independent‐groups design. Subjects were assigned randomly to either placebo, diazepam or hyoscine groups. Treatments were administered orally under double‐blind conditions. 3 The short‐term retention of digits was impaired to an equivalent degree and locus for both drugs (P less than 0.05). This effect was ascribed to the action on primary memory. 4 The drugs produced no significant effects on the recall of categorizable lists either in terms of the number of words recalled or the cohesiveness of categorical recall. 5 These results demonstrate that drugs of different pharmacological actions produce isomorphic psychological deficits in memory and that 'anti‐memory' effects on one task should not be extrapolated to all aspects of memory. 1979 The British Pharmacological Society