Scientific background
Why we developed the Transdiagnostic Global Impression (TGI) scales
In psychiatric care, clinicians must routinely evaluate the severity and course of psychiatric symptoms without the support of reliable, easy-to-use biological markers. Consequently, clinical judgement, patient reports, and standardized rating scales play a central role in assessment and treatment planning. A wide range of validated instruments is available, many of which provide valuable disorder-specific information, particularly in research settings. However, everyday clinical practice often requires tools that can be applied flexibly, efficiently, and across diagnostic boundaries.
Bridging this gap between research-grade assessments and the practical realities of routine care was the starting point for developing the Transdiagnostic Global Impression (TGI) scales.
Measurement-based care in routine practice
Measurement-based care is associated with improved outcomes in psychiatry, yet its implementation in routine settings remains variable. Clinical encounters are frequently time-limited, and many patients present with complex symptom profiles that span multiple diagnostic categories. In such contexts, clinicians benefit from instruments that can support rapid assessment, longitudinal tracking, and clear communication without disrupting clinical flow. These considerations highlighted the need for a brief, broadly applicable approach that could complement existing disorder-specific measures rather than replace them.
A transdiagnostic, clinically grounded approach
The TGI scales were developed to meet this need: concise, transdiagnostic tools that enable clinicians, patients, and informants to assess, monitor, and communicate psychiatric symptom severity across diagnoses.
The TGIs provide a structured, high-level overview of symptom burden across key domains, grounded in everyday clinical judgement. They are designed to work alongside more detailed instruments, offering a unifying framework that supports clinical decision-making and longitudinal follow-up.
Conceptually, the scales build on the well-established Clinical Global Impression – Severity (CGI-S) framework, which has been widely used in both research and clinical practice for decades. Extending this familiar approach, the TGIs apply global severity ratings to multiple domains, including psychopathology, somatic health, functioning, and satisfaction.
Rigorous development and ongoing validation
The development of the TGI scales followed established methodological standards for the construction of psychiatric rating instruments. From the outset, the process was overseen by a core steering group comprising internationally recognized academic psychiatrists with extensive expertise in clinical assessment and psychometrics, including Professors Christoph Correll, Roger McIntyre, and Stefan Leucht.
Key conceptual and methodological decisions—including domain selection, scale structure, anchoring, and intended clinical use—were discussed and refined within this core group. In addition, input was sought from a broader group of senior researchers and clinicians in the field, ensuring that multiple perspectives informed the development process.
The scale development proceeded in clearly defined phases, consistent with best-practice frameworks for instrument development. Psychometric evaluation and validation of the TGI scales are ongoing, with analyses addressing validity, and sensitivity to change. Full details of the development process, methodology, and validation studies are described in the corresponding scientific publications.
Making clinical complexity visible
A central innovation of the TGI system is its visual output, referred to as “clinical maps.” Rather than presenting scores solely as numerical values, TGI ratings are translated into a graphical representation that captures the pattern, balance, and overall severity of symptoms at a glance. When used longitudinally, changes in the size and shape of this visual footprint make improvement or deterioration readily apparent.
This visualization supports:
- Rapid clinical insight during follow-up visits
- Clear communication with patients and caregivers
- A shared understanding of treatment goals and progress
Designed for real-world clinical use
From the outset, the TGIs were developed with routine practice in mind. Completion typically requires less than five minutes, integrates naturally into standard psychiatric interviews, and does not require extensive training.
Clinicians from multiple countries who evaluated the concept during development consistently highlighted its simplicity, relevance, and clinical usefulness, indicating strong willingness to incorporate the TGIs into everyday practice.
Use in research and collaboration
Researchers interested in applying the TGIs in clinical studies or real-world evidence generation are encouraged to do so, particularly where a transdiagnostic and pragmatic approach to assessment is needed. Opportunities for scientific collaboration are welcomed, including joint research initiatives and further validation work. Users are requested to cite the original scientific publications when using the scales. For inquiries regarding use, collaboration, or study proposals, please use the contact option available at the bottom of the page.
References and further reading:
Christoph U. Correll, Zsófia B. Dombi, Ágota Barabássy, György Németh, Thomas Brevig, Roger S. McIntyre. The Transdiagnostic Global Impression - Psychopathology scale (TGI-P): Initial development of a novel transdiagnostic tool for assessing, tracking, and visualising psychiatric symptom severity in everyday practice, European Neuropsychopharmacology, Volume 88, 2024, Pages 31-39, ISSN 0924-977X, DOI:
https://doi.org/10.1016/j.euroneuro.2024.07.012
McIntyre RS, Dombi ZB, Barabassy A, Brevig T, Németh G, Correll CU. Advancing measurement-based care through triangle of care: Development and feasibility of the Transdiagnostic Global Impression - Psychopathology scale for patients and informants. Eur Psychiatry. 2025 Aug 5;68(1):e118. doi: 10.1192/j.eurpsy.2025.10069. PMID: 40760868; PMCID: PMC12438986. DOI: 10.1192/j.eurpsy.2025.10069
https://pubmed.ncbi.nlm.nih.gov/40760868/