Objectives: While previous rheumatoid arthritis (RA) studies have focussed on cardiometabolic and lifestyle factors, less research has focussed on psychological variables including mood and cognitive health, and/or sleep parameters. This study reports observational, cross-sectional associations between self-reported RA, and positive rheumatoid factor (binary RF+ vs. not) prevalence with psychological/sleep data in UK Biobank. Methods: Analyses tested for associations between RA and RF+ vs. mental health (depression, anxiety, neuroticism), sleep variables and cognitive test scores in UK Biobank (total n = 484, 064 of whom 5, 722 had RA and 25, 772 had RF+ based on blood-based biomarker data). We controlled for age, sex, ethnicity, deprivation index, smoking, BMI and alcohol and used Pearson 2 and Kruskal-Wallis tests and logistic/linear regression models for categorical/continuous data respectively. Results: Those RF+ were more likely to report longer sleep duration (standardized beta β= 0.01, SE=0.004, p< 0.01). Those that self-reported RA were more likely to score higher for neuroticism (β=0.05, SE= 0.01, p< 0.001), to have difficulties getting up in the morning (odds ratio [OR] =0.57, 95% CI: 0.53-0.61, p<0.001), to have slower reaction times (β=0.02, SE= 0.008, p<0.005) and score less for fluid intelligence (β= -0.03, SE=0.01, p<0.05). Anxiety also became a significant negative predictor for RA (OR= 0.80, 95% CI: 0.67-0.95, p< 0.01).Conclusion: The current study suggests that prevalent RA, and RF+ status are associated with differences in mental health, sleep, and cognition, highlighting the importance of addressing these aspects in clinical settings and future research.