Neuroleptics and the neuroleptic-induced deficit syndrome

The first central pharmacodynamic action of chlorpromazine to be described was sedation without narcosis. The antipsychotic action and extrapyramidal symptoms were observed later. Sedation can be separated into nonspecific sedation (drowsiness, somnolence) and specific sedation (psychomotor inhibition and psychic indifference). Both types are parts of the clinical profiles of classical neuroleptics. The sedative properties of neuroleptics may contribute to the overall efficacy in the treatment of psychotic patients, depending on the clinical situation. In most patients, however, sedation is only needed for a short period, or not at all. The drug induced sedation may adversely affect the patients' well-being and functional capabilities. The term neuroleptic-induced deficit syndrome (NIDS) has been coined to focus attention on the adverse mental effects of neuroleptics. NIDS still needs to be properly defined and to be differentiated from the deficit syndrome of schizophrenia and postpsychotic depression. Assessment methods are needed to establish the incidence and prevalence of NIDS, to evaluate the importance of NIDS in the overall treatment outcome in psychoses and to facilitate development of better antipsychotic agents.