Treatment of Anxiety in Athletes Using Cognitive Behavioral Therapy: A Single-Case Experimental Design with Multiple Baselines.

Anxiety is one of the most prevalent mental health problems in athletes, yet the inclusion of athletes with clinical mental health problems in intervention studies remains limited. Furthermore, no studies to date have investigated the mechanisms of cognitive behavioral therapy (CBT) on anxiety and positive affect in athletes. Hence, the aim of the current study was to examine the effect of CBT on moderate to severe symptoms of anxiety and positive affect in athletes, as well as to investigate the mediated effects of CBT on anxiety symptoms and positive affect through rumination and acceptance. A randomized single-case multiple-baseline design was conducted with six athletes who experienced moderate to severe anxiety. Data was collected four times daily through ecological momentary assessment, and all participants received six weekly sessions of CBT. Intervention effects were analyzed using Tau and baseline-corrected Tau, and mediated effects were analyzed using a two-step approach with Tau and cross-lagged correlations. An intervention effect on anxiety was observed for two participants, while two participants showed an increase in anxiety. An intervention effect on positive affect was observed for three participants. In terms of mediation, only one participant showed evidence consistent with a mediated process in the expected direction through rumination on anxiety. These findings highlight individual variability in treatment effects and the underlying mechanisms that may help explain how interventions exert their effects. The current study underscores the complementary role of idiographic approaches alongside groupbased designs in advancing evidence on individual treatment effects and underlying mechanisms.