Reassurance and its alternatives: Overview and cognitive behavioural conceptualisation

•Excessive reassurance seeking (ERS) remains an under-researched and poorly understood behaviour.•ERS is a transdiagnostic process that resembles the compulsive behaviours seen in obsession problems.•Investigation into ERS has been hampered by a lack of adequate definition of key concepts including reassurance and support.•We offer a new approach to defining ERS to provide a conceptual framework for studying the phenomenon across disorders.•We propose a theoretical basis for considering ERS as a form of safety-seeking behaviour.