A plea for symptom-based research in psychiatry

The significant proportion of patients suffering from subthreshold diagnoses such as partial posttraumatic stress disorder (PTSD) shows that today's diagnostic entities do not fully meet the reality and needs of clinical practice. Moreover, as stated also in the recently announced concept of research domain criteria (RDoC), the use of today's traditional diagnostic systems in psychiatric research does not sufficiently promote an integrative understanding of mental disorders across multiple units of analysis from behavior to neurobiology. Besides RDoC, core symptom-based research concepts have been proposed to bridge the translational gap in psychiatry, but, unfortunately, have not yet become the rule.
First, this article briefly reviews literature on subthreshold PTSD (as an example for subthreshold diagnoses) and, second, pleas for and proposes a modified symptom-based research concept in psychiatry.
Subthreshold PTSD has, like other subthreshold psychiatric diagnoses, not yet been clearly defined. Diagnostic entities such as subthreshold PTSD are subject to a certain arbitrariness as they are mainly the result of empiricism. This fact stresses the urgent need for neurobiologically-informed psychiatric diagnoses and motivated the here-presented proposal of a symptom-based research concept. As proposed here, and before by other researchers, symptom-based research in psychiatry should refrain from studying patient cohorts compiled according to diagnoses but, instead, should focus on assessing cohorts grouped according to chief complaints or predominant psychopathological symptoms.
The linkage of the RDoC concept and symptom-based psychiatric research might probably speed up the definition of biologically or symptom-based psychiatric diagnoses, which might replace the auxiliary constructs of “traditional” diagnoses such as full and subthreshold PTSD, and promote the development of novel psychological and pharmacological treatments.

有相当比例的患者罹患亚阈值诊断相关病症，例如部分性创伤后应激障碍（partial posttraumatic stress disorder, PTSD），这一现象表明当前的诊断范畴未能完全契合临床实践的现实与需求。此外，正如近期公布的研究领域标准（research domain criteria, RDoC）理念所阐明的，当前精神医学研究中采用的传统诊断系统，无法充分推动从行为到神经生物学的多分析维度下对精神障碍的整合性认知。除RDoC之外，学界已提出基于核心症状的研究理念，以弥合精神医学领域的转化鸿沟，但遗憾的是此类理念尚未成为主流研究范式。

首先，本文将简要回顾以亚阈值创伤后应激障碍为代表的亚阈值诊断相关研究文献；其次，本文呼吁并提出一种改良版的精神医学基于症状的研究理念。

与其他亚阈值精神科诊断类似，亚阈值创伤后应激障碍目前尚未得到明确界定。诸如亚阈值创伤后应激障碍这类诊断范畴具有一定的任意性，其本质主要源于经验主义。这一现状凸显了对具备神经生物学依据的精神科诊断的迫切需求，也推动了本文所提出的基于症状的研究理念。正如本文所倡议以及此前其他研究者的主张，精神医学领域的基于症状的研究应摒弃按照诊断标准招募患者队列的模式，转而聚焦于以主诉或主要精神病理症状为依据进行分组的队列评估。

将RDoC理念与基于症状的精神医学研究相结合，或可加快基于生物学或症状的精神科诊断的制定进程，此类诊断有望取代“传统”诊断（如完全性及亚阈值创伤后应激障碍）的辅助性框架，并推动新型心理治疗与药物治疗手段的开发。