COHEN S
Calif Med. 1958 Dec;89(6):417-9.
Evaluation of tranquilizing drugs is more difficult by any technique than evaluation of drugs given for purely organic effect, since both the symptom and its evidences are conditioned by profound psychic values. Difficult as it is to match psychiatric patients as controls, it is equally difficult to use each patient as his own control, since his reaction either to drug or to placebo may be strongly affected by previous experience with the other dose or with other drugs. In a "double blind, double cross" test comparing the values of prochlorperazine and phenobarbital, the controller misled the observers by maintaining the same drug for each patient during the entire test period. The observers detected that the test was not going according to plan, and when the "double cross" was revealed they were able to guess fairly well which patients had received each drug. The experiment not only sharpened their future observation, but demonstrated the reliability of trained clinical judgment in evaluating drugs when bias is eliminated.
与评估具有纯粹器质性效应的药物相比，采用任何技术评估镇静药物都更加困难，因为症状及其表现都受到深刻心理因素的制约。虽然将精神病患者作为对照很难匹配，但将每个患者作为自身对照同样困难，因为他对药物或安慰剂的反应可能会受到先前使用另一剂量药物或其他药物的强烈影响。在一项比较氯丙嗪和苯巴比妥效果的“双盲、双交叉”试验中，控制者在整个试验期间对每位患者都使用同一种药物，从而误导了观察者。观察者察觉到试验未按计划进行，当“双交叉”情况被揭示时，他们能够相当准确地猜出哪些患者服用了哪种药物。该实验不仅提高了他们未来的观察能力，还证明了在消除偏差时，经过训练的临床判断在评估药物方面的可靠性。
