Background

The PHQ-9 is a self-administered depression screening instrument. Little is known about its utility and accuracy in detecting depression in adults with dissociative seizures (DS).

Objectives

Using the Mini – International Neuropsychiatric Interview as a reference, we evaluated the diagnostic accuracy of the PHQ-9 in adults with DS, and examined its convergent and discriminant validity and uniformity.

Methods

Our sample comprised 368 people with DS who completed the pre-randomisation assessment of the CODES trial. The uniformity of the PHQ-9 was determined using factor analysis for categorical data. Optimal cut-offs were determined using the area under the curve (AUC), Youden Index, and diagnostic odds ratio (DOR). Convergent and discriminant validity were assessed against pre-randomisation measures.

Results

Internal consistency of the PHQ-9 was high (α = 0.87). While the diagnostic odds ratio suggested that a cut-off of ≥10 had the best predictive performance (DOR = 14.7), specificity at this cut off was only 0.49. AUC (0.74) and Youden Index (0.48) suggested a ≥ 13 cut-off would yield an optimal sensitivity (0.81) and specificity (0.67) balance. However, a cut-off score of ≥20 would be required to match specificity resulting from a cut-off of ≥13 in other medical conditions. We found good convergent and discriminant validity and one main factor for the PHQ-9.

Conclusions

In terms of internal consistency and structure, our findings were consistent with previous validation studies but indicated that a higher cut-off would be required to identify DS patients with depression with similar specificity achieved with PHQ-9 screening in different clinical and non-clinical populations.

中文翻译：

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PHQ-9 在分离性癫痫成人患者中的验证

背景

PHQ-9 是一种自我管理的抑郁症筛查工具。人们对其在检测分离性癫痫 (DS) 成人抑郁症中的实用性和准确性知之甚少。

目标

使用 Mini – International Neuropsychiatric Interview 作为参考，我们评估了 PHQ-9 在成人 DS 中的诊断准确性，并检查了其收敛性和判别性有效性和一致性。

方法

我们的样本包括 368 名完成 CODES 试验随机化前评估的 DS 患者。PHQ-9 的一致性是使用分类数据的因子分析确定的。使用曲线下面积 (AUC)、约登指数和诊断优势比 (DOR) 确定最佳截断值。根据随机化前的措施评估收敛效度和区分效度。

结果

PHQ-9 的内部一致性很高（α = 0.87）。虽然诊断优势比表明 ≥ 10 的临界值具有最佳预测性能 (DOR = 14.7)，但该临界值的特异性仅为 0.49。AUC (0.74) 和约登指数 (0.48) 表明 ≥ 13 的临界值会产生最佳的灵敏度 (0.81) 和特异性 (0.67) 平衡。然而，需要 ≥ 20 的临界值才能匹配其他医疗条件下 ≥ 13 的临界值所产生的特异性。我们发现 PHQ-9 具有良好的收敛效度和判别效度，这是 PHQ-9 的一个主要因素。

结论

在内部一致性和结构方面，我们的研究结果与之前的验证研究一致，但表明需要更高的临界值来识别具有相似特异性的抑郁症 DS 患者，这些患者在不同临床和非临床人群中通过 PHQ-9 筛查获得了相似的特异性.