May P R, Tuma A H, Dixon W J
J Nerv Ment Dis. 1977 Oct;165(4):231-9. doi: 10.1097/00005053-197710000-00002.
It has been suggested that psychotherapy makes some persons better and some worse, and that this might account for the findings of some studies that there was no significant difference between the mean improvement scores of psychotherapy and control groups. The results of a controlled study indicate, however, that psychotherapy alone did not significantly increase outcome variance in schizophrenia by comparison to a control group. In fact, there was a nonsignificant tendency to decreased variability. Ataraxic drugs alone, psychotherapy plus ataraxic drugs, and ECT had significant variance-reducing effects. There is no convincing evidence, either in the literature or from the findings of this study, that a greater outcome variability results from psychotherapy than that resulting from hospitalization and nursing care (control). Our findings support the view that by comparison with a control group, a treatment for schizophrenia reduces outcome variance in proportion to its efficacy on the particular criterion under study.
有人认为心理治疗会让一些人病情好转，而让另一些人病情恶化，这可能解释了一些研究的结果，即心理治疗组和对照组的平均改善得分没有显著差异。然而，一项对照研究的结果表明，与对照组相比，单纯心理治疗并没有显著增加精神分裂症的疗效差异。事实上，存在一种不显著的变异性降低趋势。单纯使用镇静药物、心理治疗加镇静药物以及电休克治疗都有显著的降低差异的效果。无论是在文献中还是在本研究的结果中，都没有令人信服的证据表明心理治疗比住院治疗和护理（对照）导致更大的疗效差异。我们的研究结果支持这样一种观点，即与对照组相比，针对精神分裂症的治疗会根据其对所研究的特定标准的疗效成比例地降低疗效差异。
