title: Clinical relevance of response and improvement in psychopharmacology: European College of Neuropsychopharmacology.
abstract: The use of responder categories may provide more clinically relevant information than mean differences on a severity scale but is not a definitive solution. Responder analysis is more useful in moderate illness than in mild or severe illness, depends on the timing of the analysis, and on the variance in the sample. Nevertheless, a statistically significant difference between drug and placebo treatment with respect to the percentage responders defined as a pre-established degree of reduction on a pivotal severity scale may provide the most objective information about clinical relevance yet available. Using distributions of categories of response may be less restrictive and provide a better description of results but more data are needed before conclusions can be reached. Effect size is an attractive, apparently simple method of establishing clinical relevance but criteria are lacking on cutoffs for accepting an effect size as relevant. There is a need for more information on patient samples, a better exploration of the conditions affecting response, and a better description of outcome than a single point. There are no accepted firm criteria for the clinical relevance of differences observed. There is insufficient precision in outcome measures as they currently used to set up rules. It is proposed that the criteria under discussion are interesting and need to be further investigated. More data are needed on the expected range of response, the range of size of effect of drugs, the range of response categories to drugs, and the conditions affecting response. This information is available in the large databases from clinical trial programmes of the pharmaceutical industry and a coordinated examination of available databases would provide a fruitful basis for arriving at a worthwhile estimate of the clinical relevance of psychotropic drug effects.
mesh_terms: D005060:Europe; D006801:Humans; D007557:Israel; D001523:Mental Disorders / Q000188:drug therapy* / Q000523:psychology; D011600:Psychopharmacology / Q000639:trends*; D011619:Psychotropic Drugs / Q000627:therapeutic use*; D012107:Research Design
chemical_list: D011619:Psychotropic Drugs