Supplementary Material for: Prediction of Therapeutic Outcome in a Naturalistic Setting Using Pretreatment Psychological Distress Indicators

Background: Outcome predictions allow to improve psychotherapy and to increase economic benefit. The efficient translation into practice requires simple prediction methods. The present study evaluates the prediction of treatment outcome based on initial distress level. Methods: Routine data of a university psychotherapy outpatient clinic were used (N = 3,145, Mage = 35.8, 67% female). Low versus high distress patients (classified by overall psychological distress, symptomatology, and previous treatment) were compared on total reduction in psychopathology, (early) response, remission, and premature treatment discontinuation using t tests and logistic regressions. Response and remission were assessed via relative (percentage improvement) and absolute measures (Reliable Change Index; RCI). Results: Distress level was inversely related to percentage improvement (OR = 0.62) and remission (OR = 0.34). It was positively related to total reduction in psychopathology (d = 0.63), RCI response (OR = 2.37), and treatment discontinuation (OR = 2.15). Early response and treatment discontinuation partially mediated the relationship between distress level and treatment outcome. Conclusions: Treatment success tends to be lower when initial distress is high, but this finding appears contingent on the operationalization of treatment outcome. The presented classification approach is easy to implement in practice and may be useful in order to counter an excessive workload in psychotherapy trainees.

研究背景：治疗结局预测可助力优化心理治疗实践，并提升临床经济效益。将此类研究成果高效转化至临床应用，需依托简便易用的预测方法。本研究针对基于初始痛苦水平的治疗结局预测展开评估。研究方法：本研究采用某大学附属心理治疗门诊的常规诊疗数据（样本量N=3145，平均年龄Mage=35.8岁，女性占比67%）。依据整体心理痛苦水平、症状表现及既往治疗史，将受试者划分为高痛苦组与低痛苦组；通过t检验与逻辑回归分析，比较两组在精神病理学症状总减分率、（早期）应答情况、症状缓解情况及治疗过早脱落率方面的差异。其中，应答与缓解情况分别通过相对指标（百分比改善率）与绝对指标（可靠变化指数，Reliable Change Index, RCI）进行评估。研究结果：初始痛苦水平与症状改善百分比（优势比Odds Ratio, OR=0.62）及症状缓解情况（OR=0.34）呈负相关；同时，初始痛苦水平与精神病理学症状总减分（效应量d=0.63）、基于RCI的应答情况（OR=2.37）及治疗脱落率（OR=2.15）呈正相关。早期应答与治疗脱落在初始痛苦水平与治疗结局的关联中发挥部分中介作用。研究结论：初始痛苦水平较高的患者，其治疗成功率往往偏低，但该结论似乎会因治疗结局的操作定义不同而存在差异。本研究提出的分组分类方法实操简便，可有效缓解心理治疗受训人员的过重工作负担。