Stupor refers to a group of diverse syndromes with different expressions resulting from the current underlying mental state. However, elaborate symptomatic examination of stupor is fast losing its place in the field. The recognition that catatonia is the single common syndrome observed in various mental disorders has become widespread, and the concept of catatonia gradually expanded through definitions based on operational criteria. Currently, evaluations in which the diagnosis of catatonia is only based on the presence of stupor are prevalent in both diagnostic criteria and clinical practice. In the present study, the author reviewed the conceptual definitions of stupor and catatonia along with their historical origins, and re-examined their conceptual relationships and clinical application. The findings highlighted that: 1) not all stupor should be included in catatonia; 2) contrary to the policy of uniform treatment in catatonia, subtype differentiation is effective for treating stupor;and 3)because of this expansion, the concept of catatonia has internal heterogeneity that creates challenges for clinical practice and research. In the context of such confusion, it should be noted that there have been procedural problems in revising diagnostic criteria. Many empirical studies have been conducted without rigor in data collection (i. e., evaluation of psychiatric symptoms). This means the validity of the disease concept has been diminished in the process of revising criteria based on the results of such studies. Unified psychiatric semiology should be established to make empirical research on mental illness more productive.
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