Higher therapy session frequency has been found to result in faster recovery, but few studies have considered that clients follow diverse trajectories of change in psychotherapy. It is unknown how session frequency may affect the sizes and shapes of change trajectories. The present study examined clients' change trajectories in weekly and biweekly therapy in a naturalistic setting, as well as predictors of these trajectories. Using a sample of 5,102 clients receiving 3-10 therapy sessions at a university counseling center, we identified 886 clients attending approximately weekly therapy and 1,753 clients attending approximately biweekly therapy. We examined the change trajectories of the weekly and biweekly samples using latent growth mixture modeling (LGMM). Three trajectories were identified in weekly therapy: slow change (78.33%), early improvement (17.61%), and worse before better (4.06%), and in biweekly therapy: slow change (80.38%), early improvement (13.52%), and worse before better (6.1%). The worse before better subgroup in weekly therapy experienced greater deterioration than those in biweekly therapy. The slow change and early improvement subgroups in weekly therapy showed treatment outcome comparable to those of their respective counterparts in biweekly therapy. Clients' intake symptoms, including eating concerns, frustration/anger, depression, and academic concerns, significantly predicted change trajectories. Compared to biweekly therapy, weekly therapy leads to higher chances of early improvement and shortens the duration of suffering but results in greater deterioration for individuals who deteriorate in therapy. The impact of session frequency on treatment outcome varies across clients, and session frequency should be adjusted individually. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

中文翻译：

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每周和每两周治疗的变化轨迹。

研究发现，较高的治疗频率可以加快康复速度，但很少有研究认为客户在心理治疗中遵循不同的变化轨迹。目前尚不清楚会话频率如何影响变化轨迹的大小和形状。本研究在自然环境下检查了客户在每周和每两周治疗中的变化轨迹，以及这些轨迹的预测因素。通过使用在大学咨询中心接受 3-10 次治疗的 5,102 名客户的样本，我们确定了 886 名客户大约每周参加一次治疗，1,753 名客户大约每两周参加一次治疗。我们使用潜在生长混合模型（LGMM）检查了每周和每两周样本的变化轨迹。每周治疗确定了三种轨迹：缓慢变化（78.33％）、早期改善（17.61％）和先恶化后好转（4.06％），而每两周治疗则确定：缓慢变化（80.38％）、早期改善（13.52％）、先差后好（6.1%）。每周治疗中较佳亚组的恶化程度比每两周治疗中的亚组恶化程度更大。每周治疗的缓慢变化和早期改善亚组的治疗结果与每两周治疗的相应对应组相当。客户的摄入症状，包括饮食问题、沮丧/愤怒、抑郁和学业问题，可以显着预测变化轨迹。与每两周一次的治疗相比，每周一次的治疗可以带来更高的早期改善机会并缩短痛苦的持续时间，但对于治疗中病情恶化的个体来说，病情恶化会更大。疗程频率对治疗结果的影响因客户而异，疗程频率应单独调整。（PsycInfo 数据库记录 (c) 2023 APA，保留所有权利）。