Objective: Psychotherapy for depression is effective for many veterans, but the relationship between number of treatment sessions and symptom outcomes is not well established. The Dose-Effect model predicts that greater psychotherapeutic dose (total sessions) yields greater symptom improvement with each additional session resulting in smaller session-to-session improvement. In contrast, the Good-Enough Level (GEL) model predicts that rate of symptom improvement varies by total psychotherapeutic dose with faster improvement associated with earlier termination. This study compared the dose-effect and GEL model among veterans receiving psychotherapy for depression within the Veterans Health Administration. Method: The sample included 13,647 veterans with ≥2 sessions of psychotherapy for depression with associated Patient Health Questionnaire-9 (PHQ-9) scores in primary care (n = 7,502) and specialty mental health clinics (n = 6,145) between October 2014 and September 2018. Multilevel longitudinal modeling was used to compare the Dose-Effect and GEL models within each clinic type. Results: The GEL model demonstrated greater fit for both clinic types relative to dose-effect models. In both treatment settings, veterans with fewer sessions improved faster than those with more sessions. In primary care clinics, veterans who received 4-8 total sessions achieved similar levels of symptom response. In specialty mental health clinics, increased psychotherapeutic dose was associated with greater treatment response up to 16 sessions. Veterans receiving 20 sessions demonstrated minimal treatment response. Conclusions: These findings support the GEL model and suggest a flexible approach to determining length of psychotherapy for depression may be useful for optimizing treatment response and allocation of clinical resources. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

中文翻译：

---

VA患者的心理治疗和抑郁症状轨迹：比较剂量效应和足够好的水平模型。

目的：抑郁症的心理治疗对许多退伍军人有效，但治疗次数与症状结果之间的关系尚不明确。剂量效应模型预测，更大的心理治疗剂量（总疗程）会产生更大的症状改善，每次额外疗程导致较小的疗程间改善。相比之下，足够好水平 (GEL) 模型预测症状改善率因总心理治疗剂量而异，较早终止与较快改善相关。这项研究比较了退伍军人健康管理局内接受抑郁症心理治疗的退伍军人的剂量效应和 GEL 模型。方法：样本包括13个，2014 年 10 月至 2018 年 9 月期间，647 名退伍军人在初级保健 (n = 7,502) 和专业心理健康诊所 (n = 6,145) 中接受了 ≥2 次抑郁症心理治疗并获得相关的患者健康问卷 9 (PHQ-9) 评分。多层次纵向建模用于比较每种诊所类型中的剂量效应和凝胶模型。结果：相对于剂量效应模型，GEL 模型显示出更适合两种临床类型。在这两种治疗环境中，治疗次数较少的退伍军人比治疗次数较多的退伍军人改善得更快。在初级保健诊所，总共接受 4-8 次治疗的退伍军人取得了相似水平的症状反应。在专业心理健康诊所，增加心理治疗剂量与更大的治疗反应相关，最多可达 16 次。接受 20 次治疗的退伍军人表现出最小的治疗反应。结论：这些发现支持 GEL 模型，并提出了一种灵活的方法来确定抑郁症心理治疗的时间长度，这可能有助于优化治疗反应和临床资源的分配。（PsycInfo 数据库记录 (c) 2021 APA，保留所有权利）。