Experience sampling methods have been used to study symptomatology and functioning in schizophrenia and first-episode psychosis (FEP). However, few studies have used daily diaries to measure experiences such as mood and social functioning in FEP. We sought to first identify predictors of daily diary compliance in a sample of 38 individuals with FEP. Second, we assessed the relationship between daily diary ratings and clinician-administered assessments at mid-treatment and post-treatment. Finally, we evaluated the effect of I-CAT, a mindfulness and positive therapy-based intervention, on daily diary ratings of happiness, sadness, stress, relaxation, adaptation, and social interactions compared to Treatment as Usual (TAU). We found no significant predictors of daily diary compliance, though participants with higher completion rates had higher average social functioning scores. The diary was significantly related to clinician-administered assessments at mid-treatment on domains of happiness, sadness, stress, and relaxation. Finally, ICAT did not have a significant impact on daily diary ratings relative to TAU.Bachelor of Scienc
