• bipolar disorder
• mood disorders
• vitamin D

Because of its possible involvement in the pathogenesis of various mental diseases, particularly mood disorders (MDs), vitamin D, a pleiotropic hormone, has gained attention in neuropsychiatry. Given the relatively high frequency of hypovitaminosis D both in the general population and in certain subpopulations, such as those with the two most prevalent types of MDs, major depressive disorder (MDD) and bipolar disorders (BDs), this is especially pertinent. The purpose of the current investigation is to assess plasma vitamin D levels in a sample of inpatients who meet the DSM-5 criteria for a mood episode within BDs type 1 and 2, schizoaffective disorder and MDD given the contentious literature on this subject and the potential therapeutic implications. The clinical picture was evaluated utilizing specific rating scales. The findings demonstrated that, in varying degrees of severity, the mean vitamin D levels of the patients were significantly lower than the normative values. Regarding various sociodemographic or clinical variables, no differences were found. The current research, in our opinion, confirms other studies showing lower vitamin D levels in bipolar patients and supports the function of this neurohormone in BDs. However, additional research is required to confirm our findings and explore the possible advantages of vitamin D supplementation in the management of MDs.