Frigerio S, et al. - By analyzing literature, it was inquired herein if caffeine intake/withdrawal influence the natural course of bipolar disorder (BD), in terms of clinical results. All relevant studies were identified from PubMed, Embase and PsycINFO. There were 1678 records reviewed, of which, 17 studies satisfied the inclusion criteria (10 case reports, 1 retrospective cohort study, 5 cross-sectional studies, 1 interventional study). As noted by researchers, the literature assessing clinical impacts of caffeine in BD patients is not conclusive. In BD cases, manic symptoms occurrence may be preceded by acute increases in caffeine intake, this happens potentially via a direct stimulant impact, influencing sleep patterns and/or the metabolism of lithium or other medications, although increases in caffeine consumption could also result from an ongoing manic relapse or a prodromal sign.