Keeping the body in mind: Development of the Transdiagnostic Global Impression–Somatic Symptoms and Signs (TGI-3S) scale

Abstract

Abstract Background It is well-established that mental illness is associated with excess and premature mortality. Consequently, the assessment of physical health should be routine in the evaluation of persons living with mental disorders. Herein, we introduce the development of a global instrument to assess physical health status in persons with mental disorders. Methods Following the development of the Transdiagnostic Global Impression–Psychopathology (TGI-P) scale, a novel scale of physical health status, the Transdiagnostic Global Impression–Somatic Symptoms and Signs (TGI-3S), was created using similar principles. Scale development followed a multistage process involving (1) item generation using deductive methods, (2) two content validations by an expert panel, and (3) two iterative usability-testing rounds with patients and caregivers. These rounds therefore assessed understandability and ease of use for wording, visual format, and emotional/cognitive load of the instrument. The psychometric validation is underway. Results The TGI-3S was developed as a front-end screening tool resulting in a broad somatic burden map, rather than a diagnostic instrument. Throughout the development process, experts, patients, and caregivers evaluated the TGI-3S positively. In the final usability round, 96% found the aim of the scale clear, and 87% considered the instructions easy to follow. The scale demonstrated high-level usability, with 72% completing the TGI-3S in <5 minutes. Emotional and cognitive burden of completing the TGI-3S was rated as low, and item wording was well-understood. Conclusions With psychometric validation underway, the TGI-3S offers an anamnesis-embedded, brief, yet comprehensive tool for facilitating the assessment of somatic health in patients with mental disorders.