Department of Psychology, Temple University, Philadelphia, USA.
Department of Psychiatry, McLean Hospital/Harvard University Medical School, Boston, USA.
Mol Psychiatry. 2022 Mar;27(3):1281-1285. doi: 10.1038/s41380-021-01414-5. Epub 2022 Jan 8.
There is increasing appreciation that certain biological processes may not be equally related to all psychiatric symptoms in a given diagnostic category. Research on the biological phenotyping of psychopathology has begun examining the etiological and treatment implications of identified biotypes; however, little attention has been paid to a critical methodological implication of these results: measurement noninvariance. Measurement invariance is the ability of an instrument to measure the same construct, the same way, across different people, or across different time points for the same individual. If what a measure quantifies differs across different people (e.g., those with or without a particular biotype) or time points, then it is invalid to directly compare means on that measure. Using a running example of inflammatory phenotypes of depression, we first describe the biological phenotyping of psychopathology. Second, we discuss three types of measurement invariance. Third, we demonstrate how differential biology-symptom associations invariably creates measurement noninvariance using a theoretical example and simulated data (for which code is provided). We also show how this issue can lead to false conclusions about the broader diagnostic construct. Finally, we provide several suggestions for addressing these important issues to help advance the field of biological psychiatry.
越来越多的人认识到，某些生物过程可能与特定诊断类别中的所有精神症状并不完全相关。精神病理学的生物表型研究开始研究已确定的生物型的病因和治疗意义；然而，这些结果的一个关键方法学意义却很少受到关注：测量不变性。测量不变性是指一种工具在不同人群或同一人群的不同时间点测量相同结构、以相同方式测量的能力。如果一个测量工具在不同人群（例如，具有或不具有特定生物型的人群）或时间点上测量的内容不同，那么直接比较该测量工具上的平均值是无效的。我们使用抑郁炎症表型的示例来说明，首先描述精神病理学的生物表型。其次，我们讨论了三种类型的测量不变性。第三，我们使用理论示例和模拟数据（提供了代码）演示了如何通过不同的生物学-症状关联始终创建测量不变性。我们还展示了这个问题如何导致对更广泛的诊断结构的错误结论。最后，我们提供了一些解决这些重要问题的建议，以帮助推进生物精神病学领域的发展。
