Substances are tested and when it is found that they have beneficial effects on certain conditions, outweighing negative side-effects in individuals with these

Substances are tested and when it is found that they have beneficial effects on certain conditions, outweighing negative side-effects in individuals with these conditions - they are accepted for use after clinical phases. Would you rather have no meds for some conditions because we don't fully understand how existing ones work, or would you dissect living humans' brains for faster research?