Utilization of internet-delivered cognitive behavioural therapy (iCBT) for treating depression and anxiety disorders in stepped-care models, such as the UK’s Improving Access to Psychological Therapies (IAPT), is a potential solution for addressing the treatment gap in mental health. We investigated the effectiveness and cost-effectiveness of iCBT when fully integrated within IAPT stepped-care settings. We conducted an 8-week pragmatic randomized controlled trial with a 2:1 (iCBT intervention: waiting-list) allocation, for participants referred to an IAPT Step 2 service with depression and anxiety symptoms (Trial registration: ISRCTN91967124). The primary outcomes measures were PHQ-9 (depressive symptoms) and GAD-7 (anxiety symptoms) and WSAS (functional impairment) as a secondary outcome. The cost-effectiveness analysis was based on EQ-5D-5L (preference-based health status) to elicit the quality-adjust life year (QALY) and a modified-Client Service Receipt Inventory (care resource-use). Diagnostic interviews were administered at baseline and 3 months. Three-hundred and sixty-one participants were randomized (iCBT, 241; waiting-list, 120). Intention-to-treat analyses showed significant interaction effects for the PHQ-9 (b = −2.75, 95% CI −4.00, −1.50) and GAD-7 (b = −2.79, 95% CI −4.00, −1.58) in favour of iCBT at 8-week and further improvements observed up to 12-months. Over 8-weeks the probability of cost-effectiveness was 46.6% if decision makers are willing to pay £30,000 per QALY, increasing to 91.2% when the control-arm’s outcomes and costs were extrapolated over 12-months. Results indicate that iCBT for depression and anxiety is effective and potentially cost-effective in the long-term within IAPT. Upscaling the use of iCBT as part of stepped care could help to enhance IAPT outcomes. The pragmatic trial design supports the ecological validity of the findings.

利用互联网提供的认知行为疗法（iCBT）在阶梯式护理模式中治疗抑郁症和焦虑症，例如英国的改善心理治疗的可及性（IAPT），是解决心理健康治疗差距的潜在解决方案。我们研究了 iCBT 完全集成到 IAPT 分级护理环境中时的有效性和成本效益。我们进行了一项为期 8 周的实用随机对照试验，采用 2:1（iCBT 干预：等待名单）分配，对象为患有抑郁和焦虑症状的 IAPT 第 2 步服务参与者（试验注册：ISRCTN91967124）。主要结局指标是 PHQ-9（抑郁症状）和 GAD-7（焦虑症状），次要结局指标是 WSAS（功能障碍）。成本效益分析基于 EQ-5D-5L（基于偏好的健康状况），以得出质量调整生命年 (QALY) 和修改后的客户服务收据清单（护理资源使用）。在基线和 3 个月时进行诊断访谈。361 名参与者被随机分配（iCBT，241 人；等候名单，120 人）。意向治疗分析显示 PHQ-9 ( b  = -2.75, 95% CI -4.00, -1.50) 和 GAD-7 ( b  = -2.79, 95% CI -4.00, -1.58)之间存在显着的交互作用8 周时 iCBT 受到青睐，并在 12 个月内观察到进一步改善。如果决策者愿意为每个 QALY 支付 30,000 英镑，那么在 8 周内，成本效益的概率为 46.6%，当控制臂的结果和成本在 12 个月内外推时，成本效益的概率会增加到 91.2%。结果表明，iCBT 对于抑郁和焦虑是有效的，并且从长远来看，在 IAPT 中具有潜在的成本效益。作为分级护理的一部分，扩大 iCBT 的使用可能有助于提高 IAPT 的效果。务实的试验设计支持了研究结果的生态有效性。