How to Elicit Thought Disorder During Clinical Interviews: A Practical Guide

The reliable assessment of Formal Thought Disorder (FTD), a collection of observable signs of suspected thinking dysfunction, is the cornerstone of interviewing a person with psychosis. A significant gap persists between the success of reliable assessments reported in published rating scales of FTD and the practical constraints of a clinical interview. Validated rating scales largely focus on operationalized criteria for describing items; the procedural aspects of how to elicit these signs often remain implicit. We synthesize the principles and procedures of FTD assessment embedded in rating scales, translating their design into a framework for routine clinical use. Systematic employment of several manoeuvres can help elicit FTD signs: conversational stimulation, cognitive loading, social modulation, and pointed clarifications to stress-test thought, language and communication processes. By making these procedures explicit, we aim to equip clinicians and trainees with a strategic, measurement theory-informed approach to the psychiatric interview when assessing for FTD.