Thymosthenic effects of ritanserin (R 55667), a centrally acting serotonin‐S₂ receptor blocker

Abstract

Abstract Ritanserin, characterized as a long‐acting serotonin‐S 2 antagonist and as a pure and selective antagonist of LSD discrimination in rats, was found to be effective in the treatment of anxiety states. In these studies the observation that the patients felt less tired and more energetic with improved mood has led to study the effects of ritanserin 10 mg b.i.d. in dysthymic disorder and chronic schizophrenia, two conditions with a predominant symptomatology of anergy. The results obtained from two separate placebo‐controlled studies showed significant improvement of depressive mood, early insomnia, agitation, and psychic anxiety in the dysthymic group, whereas negative and affective symptoms showed the best improvement in the schizophrenic group under concurrent decrease of extrapyramidal symptomatology. In both diagnostic groups the drug treatment was very well tolerated. Based on the results that ritanserin showed predominant improvement of anergy and depressed mood, the drug was ascribed thymosthenic properties, which are further supported by the specific property of ritanserin to increase human slow wave sleep.