Tolerating Uncertainty: Short- and Long-Term Effects of Sudden Gains in Behavioral Experiments for Generalized Anxiety Disorder

Sudden gains are significant symptom improvements occurring between therapy sessions. Approximately 20% of individuals with generalized anxiety disorder (GAD) experience sudden gains during psychotherapy (Deschênes and Dugas in Cogn Ther Res 37:805–811, 2013. https://​doi.​org/​10.​1007/​s10608-012-9504-1; Flückiger et al. in J Consult Clin Psychol 89(5):454, 2021. https://​doi.​org/​10.​1037/​ccp0000639). This study explores the frequency and impact of sudden gains during a novel cognitive-behavioral treatment (CBT) for GAD—Behavioral Experiments for Intolerance of Uncertainty (Dugas et al. in Behav Ther 53(6):1147–1160, 2022. https://​doi.​org/​10.​1016/​j.​beth.​2022.​05.​003)—a treatment designed to reduce intolerance of uncertainty via behavioral experiments that expose individuals to uncertainty-inducing situations and help them develop more adaptive beliefs and emotional reactions toward uncertainty (Robichaud et al. in Cognitive behavioral treatment for generalized anxiety disorder: from science to practice, Routledge, London, 2019).

The study tested three hypotheses: (1) at least 20% of participants would experience a sudden gain, (2) participants with sudden gains would demonstrate greater progress during treatment, and (3) these improvements would persist at 6-month follow-up. Forty-eight (48) adults with primary GAD completed 12 sessions of CBT. Sudden gains were identified using the Penn State Worry Questionnaire—Past Week (PSWQ-PW; Stöber and Bittencourt in Behav Res Ther 36(6):645–656, 1998. https://​doi.​org/​10.​1016/​S0005-7967(98)00031-X), which was administered weekly during treatment. GAD symptoms were assessed with the Worry and Anxiety Questionnaire (WAQ; Dugas et al. in Journal de Thérapie Comportementale et Cognitive 11:31–36, 2001) administered at baseline, post-treatment, and 6-month follow-up to track symptom changes over time.

Fifteen participants (31.25%) experienced a sudden gain. Mixed ANOVAs revealed that participants with sudden gains achieved significantly greater symptom reductions from pre- to post-treatment (WAQ [F(1,46) = 4.51, p =.039, partial η² =.09]). These improvements were sustained at 6-month follow-up (WAQ [F(2,82) = 4.91, p =.01, partial η² =.11]).

Sudden gains during CBT for GAD are both frequent and impactful. In the context of Behavioral Experiments for Intolerance of Uncertainty, these gains contribute to superior outcomes observed at post-treatment and sustained over the long term. Their mechanisms of action and implications for enhancing treatment efficacy warrant further investigation.