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.

Lacking biomarkers in psychiatry calls for a valid and reliable assessment of psychopathology across mental disorders that is easy to use, bridges research and clinical care, and that can capture clinician and patient perspectives. Herein we propose, a novel, brief, transdiagnostic tool to assess and visualize symptom severity in different psychiatric disorders. The Transdiagnostic Global Impression - Psychopathology scale (TGI-P) is based on the Clinical Global Impression - Severity scale (CGI-S), which was originally designed to measure global illness severity in one score. The TGI-P covers 10 transdiagnostic symptom domains and similar to the CGI-S, it is rated on a 7-point Likert-scale from 1 (normal) to 7 (extreme). These ten domains include positive symptoms, negative symptoms, manic symptoms, depressive symptoms, addiction symptoms, cognitive symptoms, anxiety symptoms, sleep symptoms, hostility symptoms, and self-harm symptoms. The results are visually presented, thus simplifying the monitoring of symptoms, and facilitating discussion with patients and caregivers. As part of the development process, the TGI-P was surveyed among 36 psychiatrists from 3 countries. Importantly, over 80 % of them was "very positive" or "positive" about the concept of the tool, and most of them (70 %) reported willingness to use it in their everyday practice. Further psychometric development and testing of the TGI-P is underway alongside future TGI scales covering adverse events, functioning and satisfaction.