Intolerance of Uncertainty and Intolerance of Ambiguity: Similarities and differences

In the model of Generalised Anxiety Disorder (GAD) proposed by Dugas, Gagnon, Ladouceur, and Freeston (1998), Intolerance of Uncertainty (IU) plays a central role in the acquisition and maintenance of worries. A similar concept, Intolerance of Ambiguity (IA) was introduced by Frenkel-Brunswik 50 years ago. For decades, IU has been confused with IA. Researchers have applied them interchangeably. The main goal of this paper is to clarify and differentiate the notions of IU and IA, as well as to suggest new research avenues.