Effects and Mechanisms of Change of Internet Delivered Cognitive Behavior Therapy for Generalized Anxiety Disorder

The goal of this clinical trial is to compare two psychological treatments for Generalized Anxiety Disorder. The main questions it aims to answer are: How well do these treatments work compared to earlier studies? Is one of the treatments more effective than the other? Are the treatments working the way that we think they do? Specifically, do changes in the variables that these treatments aim to target predict changes in anxiety symptoms? Participants will be randomized to two different internet-based cognitive behavioral therapy (ICBT) programs: Intolerance of uncertainty-based ICBT and metacognition-based ICBT. Both programs consist of 8 treatment modules and run for 10 weeks. A psychologist will respond to the participants assignments and exercises and will respond to messages.