INTRODUCTION Research indicates that individuals with generalized anxiety disorder (GAD) may experience deficits in positive affect (PA), and tend to dampen or intentionally suppress PA. Despite the presence of PA-related pathology in GAD, little is known about change in PA during GAD treatment. OBJECTIVE This study examines changes in PA, negative affect (NA) and worry in seven participants during cognitive behavioral therapy (CBT) for GAD. METHOD Intensive repeated measures (i.e., time series) data were subjected to person-specific regression analysis to delineate individual change trajectories. RESULTS Significant improvement in worry was observed in all but one participant. Fear and irritability - indices of NA - each improved in 5/7 participants while sadness improved in 4/7 participants (worsening in one). Of all symptom domains, PA had the poorest treatment response: PA improved in only 2/7 participants and actually significantly worsened in 5/7 individuals even as NA and worry improved during therapy. CONCLUSION These findings indicate that treatment gains from traditional CBT for GAD may not generalize to improvements in PA regulation, or even emotional functioning more broadly. This evidence is a call to increase the focus on PA regulation in treatment for GAD; perhaps PA could be a missing piece in our understanding of ways to bolster GAD treatment outcomes.