Incipient aggression in psychiatric or forensic settings: threat behaviour escalation and prediction

Aggression toward staff by individuals in psychiatric and forensic populations remains a persistent risk, often preceded by observable behavioural cues that are overlooked in formal risk frameworks. While structured assessment tools typically rely on historical or diagnostic factors, they lack sensitivity to the short-term, escalating behaviours that can signal imminent assault. Drawing from ethology, clinical observation, and forensic psychology, this paper synthesises evidence on non-verbal indicators of incipient aggression—such as gaze fixation, postural changes, and spatial intrusion. Particular attention is given to the ‘square-up’ posture as an illustrative example of a high-salience, visually recognisable signal. We argue for the development of a behavioural risk hierarchy that captures the sequential nature of increasing threat, offering a more dynamic and context-sensitive approach to risk assessment. Integrating findings from comparative aggression studies, observational research, and clinical practice, this paper outlines a conceptual framework for interpreting early threat behaviours and highlights opportunities for earlier interventions.