Background and Aims: Ramadan intermittent fasting (RIF) involves significant shifts in sleep patterns and circadian rhythms that may affect neurological health. This study aimed to evaluate changes in neuropsychiatric and neurocognitive functions in relation to sleep quality among healthy adults observing RIF. Methods: We recruited healthy adults from various regions in Jordan for this prospective cohort study. We used validated self-report questionnaires to assess mental health and sleep parameters. Anxiety and depression were assessed using the GAD-7 and PHQ-9, respectively. We measured resilience using the 10-item Nicholson McBride Resilience Questionnaire (NMRQ), and the Neuro-QoL (cognitive functions domain) assessed memory and attention. We assessed sleep quality using the Pittsburgh Sleep Quality Index (PSQI). We administered all tools before (BR) and at the end of Ramadan (DR) to track changes in symptom severity and functional status. Results: A total of 723 healthy adults (mean age: 28.82 ± 12.04 years) completed both assessments. A paradoxical divergence emerged between mood and sleep parameters: mean scores for depression (PHQ-9: 8.65 to 7.70) and anxiety (GAD-7: 6.75 to 5.65; both p = 0.0001) improved significantly, with a higher proportion of participants reporting minimal symptoms during Ramadan. Conversely, overall sleep quality (PSQI) deteriorated markedly, with the percentage of participants classified as having “good sleep quality” dropping from 66.4% to 34.9% (p = 0.0001). While sleep latency and sleep disturbances improved slightly, subjective sleep quality and sleep duration worsened significantly (p ≤ 0.01). Additionally, Neuro-QoL cognitive scores decreased from 30.60 to 28.97 (p = 0.0001), whereas total resilience scores remained stable (p = 0.897). Conclusions: RIF is associated with significant improvements in depression and anxiety scores despite a concurrent deterioration in overall sleep quality and duration. While these findings suggest a favorable impact on subjective mental well-being, the observational design precludes establishing causal relationships. This paradoxical interplay between fasting-induced mood enhancements and sleep disruptions highlights the need for future prospective studies utilizing objective measurement tools.