OBJECTIVE The dose-response model of change in psychotherapy posits that each session of therapy is incrementally beneficial across patients. The contrasting good-enough level model suggests that patients improve at different rates in therapy and discontinue treatment when they are satisfied with their improvement. Support for each theory has been mixed, and many prior studies have relied on samples of patients receiving unstructured treatment approaches. We conducted this study to compare these two theories across two manualized treatments for posttraumatic stress disorder (PTSD). METHOD Two hundred eighty-four female veterans and military service members with PTSD (Mage = 44.79; 54.6% White non-Hispanic, 6.7% Black non-Hispanic, 37% other) were randomized to receive 10 sessions of prolonged exposure (PE), a trauma-focused therapy, or present-centered therapy (PCT), a non-trauma-focused therapy. Participants completed the PTSD Checklist (PCL) at even-numbered treatment sessions, and the timing of dropout/treatment completion was monitored. RESULTS The point of highest risk for dropout differed between the treatments, with risk in PE corresponding to the beginning of imaginal exposures. In the PE condition, but not in PCT, a higher number of sessions completed increased the likelihood of achieving reliable clinically significant improvement. Across treatments, the rate of change in PTSD symptoms did not differ according to the number of sessions completed (b = 0.06, p = .687). CONCLUSIONS Findings support the dose-response model of change in psychotherapy. There were notable differences in dropout across the treatment conditions, including rates, timing, and implications for outcomes. These differences likely reflect differences in content between the protocols. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

中文翻译：

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创伤后应激障碍的长期暴露和以当前为中心的治疗的治疗长度和症状改善：比较两种手动干预措施中的剂量反应和足够好水平模型。

目的 心理治疗变化的剂量反应模型认为，每次治疗对患者都逐渐有益。对比足够好水平模型表明，患者在治疗中以不同的速度改善，当他们对改善感到满意时停止治疗。对每种理论的支持参差不齐，许多先前的研究都依赖于接受非结构化治疗方法的患者样本。我们进行这项研究是为了比较这两种理论在创伤后应激障碍（PTSD）的两种手动治疗中的作用。方法 284 名患有 PTSD 的女性退伍军人和军人（法师 = 44.79；54.6% 非西班牙裔白人，6.7% 非西班牙裔黑人，37% 其他）被随机接受 10 次长期暴露 (PE) 治疗，以创伤为中心的治疗，或以当下为中心的治疗（PCT），一种非以创伤为中心的治疗。参与者在偶数治疗疗程中完成了创伤后应激障碍检查表（PCL），并监测退出/治疗完成的时间。结果 不同治疗方案中退出的最高风险点不同，PE 的风险对应于想象暴露的开始。在 PE 条件下，但在 PCT 条件下，完成的疗程次数越多，获得可靠的临床显着改善的可能性就越大。在不同的治疗中，PTSD 症状的变化率并没有根据完成的治疗次数而有所不同 (b = 0.06，p = .687)。结论 研究结果支持心理治疗变化的剂量反应模型。不同治疗条件下的退出率存在显着差异，包括比率、时间和对结果的影响。这些差异可能反映了协议之间内容的差异。（PsycInfo 数据库记录 (c) 2023 APA，保留所有权利）。