Time-blind analysis and other video-strategies in phase II trials of psychotropic drugs.

Phase-II-studies of potential psychotropic drugs present special difficulties for the investigator. They must often be performed, even in early phase II, as controlled double-blind studies because of methodological requirements. On the other side, the sample size mostly cannot be kept small, due to medical, organizational, ethical, and legal reasons. Thus, the variance of many psychological factors will easily lead to errors of the beta-type. Errors of the alpha-type are the special danger of open pilot studies in psychiatric patients. One bias of primary importance is the fact that the investigator can never remain blind as to time. Special video-techniques, developed by our psychopharmacological research group, allow to carry our time-blind analyses of normal or specially structured patient interviews. Furthermore, they provide the opportunity to expose psychopathological data obtained under normal clinical conditions to several independent raters. This procedure results in a much more standardized average rater judgement and has considerable advantages compared to documentation on conventional rating scales.