Initial dysphoric response (IDR) is characterized by a negative affective reaction within 48 h after a neuroleptic test dose. Currently, there are three scales for measuring the IDR (Neuroleptic Dysphoria Scale, Dysphoric Response Index, Drug Attitude Inventory). The debate continues about the definition, measurement, and underlying aetiology of IDR. Nevertheless, with a prevalence of 30%, the response is a clinically relevant phenomenon. Empirical data give some evidence of an association between IDR and short-term outcome. No correlation of IDR with pretreatment variables has been found yet (e.g. age, gender, and psychopathology at baseline, especially depression and hostility). With respect to aetiology, a negative subjective reaction to concurrent extrapyramidal side effects and direct dysaffective effects of some neuroleptics have been discussed. Other studies found that IDR might not be a specifically antipsychotic effect. Our first results give some evidence that patients treated with atypical antipsychotics experience IDR less often and less severely than those treated with conventional antipsychotics described in the literature. Further research should include placebo-controlled studies and the evaluation of specific pretreatment variables. To assess the aetiology of IDR, further basic research is needed.
