Comparative studies on the effects of the combination drug lorazepam plus diphenhydramine (Somnium) versus lorazepam on the noopsyche, thymopsyche and psychophysiology in nonorganic insomnia related to generalized anxiety disorder.

In a double-blind, parallel-group design study on hypnotic and anxiolytic effects of the combination drug Somnium (lorazepam 1 mg + diphenhydramine 25 mg) (SOM) as compared with 1 mg lorazepam (LOR) alone, daytime behavioral effects were studied in 44 patients with nonorganic insomnia related to a mild generalized anxiety disorder. After a placebo run-in phase of 1 week, they received active treatment for 4 weeks. Psychometric evaluations included 6 thymopsychic variables (somatic complaints, state anxiety, trait anxiety, self-rating anxiety and depression scale and adjective mood scale), 6 noopsychic variables (general, associative, numerical and total verbal memory; correct reproductions and errors-Benton visual memory test), 4 pupillary measures (pupillary diameter, latency, relative change in % and half recovery time in pupillary response) and 6 skin conductance measures (baseline, latency, ascending time, time to peak, skin conductance response and skin conductance response maximum). Multivariate statistical analysis of the thymopsyche demonstrated significant improvement after both compounds, with the combination drug significantly superior to its single component lorazepam. Also regarding noopsychic measures, Somnium was significantly superior to the single component lorazepam, as specifically verbal memory was improved after Somnium, while opposite changes occurred after lorazepam alone. Pupillary measures revealed no significant overall inter-drug differences, whereas skin conductance findings demonstrated that the combination drug Somnium was superior to the single component lorazepam also in regard to the anxiolytic effect at the autonomic nervous system level.