Double-blind cross-over clinical comparison of two 2'-chloro benzodiazepines: 7-chloro-5-(2-chlorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one (chlordesmethyldiazepam) versus 7-chloro-5-(o-chlorophenyl)-1,3-dihydro-3-hydroxy-2H-1,4-benzodiazepin-2-one (lorazepam) in neurotic anxiety.

A group of 20 female neurotic inpatients has been treated with 7-chloro-5-(2-chlorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one-(chlordesmethyldiazepan)- 7-chloro-5(o-chlorophenyl)-1,3-dihydro-3-hydroxy-2H-1,4-benzodiazepin-2-one (lorazepam) according to a double-blind cross-over design. For each drug clinical evaluations were performed by means of Hamilton's rating scale for anxiety states and of Overall and Gorham's brief psychiatric rating scale, at the beginning, after the first week and at the end of the two-week period of treatment, in opposite sequence. A statistically greater efficacy of chlordesmethyldiazepam in comparison to lorazepam was observed. Results are discussed with regard to benzodiazepine structure-activity relationships.