Bipolar disorder (BD) is a common mental condition with a seasonal pattern (SP) of onset. In the spring, there is a higher incidence rate of mania or mixed onset and suicide. However, the underlying mechanism of this SP remains unclear. In this study, targeted metabolomics was used to understand metabolic changes in patients with BD before and after the spring equinox. Nine patients with BD and matched healthy controls were tested for serum metabolomics at the spring equinox and 15 days before and after the spring equinox. The results showed that 27 metabolite levels changed significantly, three of which interacted between three time points and groups involving triglyceride (TG, 20:4_34:2), TG (20:4_34:3) and TG (16:0_36:6). The identified metabolic pathways mainly involved arginine biosynthesis, D-glutamine and D-glutamate metabolism, and nitrogen metabolism. Changes in solar radiation and lunar cycle during spring may be the external causes of metabolic changes. These findings help to further explore seasonal metabolic changes in patients with BD and provide insights into the mechanisms of patients' emotional changes in spring.
Keywords: Bipolar disorder; glutamate; metabolomics; serum; spring.