Background: Bipolar disorders (BD) are significant debilitating mental problems. Here, we introduced a novel index as a representative of the quality of care delivered to BD patients worldwide. Methods: The Global Burden of Disease (GBD) 2019 study was the primary data source on BD, including prevalence, incidence, and years lived with disability (YLDs). Secondary indices were created and transformed into a single component that accounted for most of the variation, using the Principal Component Analysis (PCA) method. This component, reported on a scale of 0 to 100, was presented as the quality of care index (QCI). The QCI was estimated in different age groups and areas within a 30-year time frame. Gender disparity ratio (GDR), as the female-to-male ratio of the QCI, was reported. Results: The Global QCI slightly increased from 50.4 in 1990 to 53.1 in 2019. The GDR value was 0.95 in 2019. The high-middle SDI quintile had the highest QCI estimate of 63.0, and the lowest QCI value of 36.9 was regarding the low SDI quintile. Western-Pacific Region and South-East Asia had the highest and lowest QCI among WHO regions, with estimates of 70.7 and 31.2, respectively. The age group of 20 to 24 years old patients reported the lowest QCI estimate of 30.2, and the highest QCI of 59.8 was regarding 40 to 44 years old patients. Conclusion: The QCI in BD had only a subtle increase from 1990 to 2019 and is in need of further improvement. Inequalities between different regions and age groups are considerable and require proper attention.