Evaluating the association of vitamin D3, parathyroid hormone, and C-reactive protein serum levels in patients with an acute psychotic episode: a cross-sectional study in tertiary centre in Iran

Background: The high impact of vitamin D on brain development and its relationship with inflammatory markers in the clinical course of psychiatric disorders have compelled researchers to investigate the potential association between vitamin D levels, C-reactive protein (CRP) levels, and the incidence of mental disorders. In the present study, we aimed to compare the serum levels of vitamin D and its related markers, including calcium, phosphorus, and parathyroid hormone (PTH), along with CRP, in 3 groups of patients with acute psychotic episodes, including schizophrenia, bipolar disorder, and methamphetamine-induced psychosis, with a standard control group of the Iranian population.

Methods: This descriptive cross-sectional study was conducted at a psychiatric hospital in Tehran, Iran, and involved a total of 185 subjects. The subjects included four groups: acute phase of schizophrenia (n = 49), acute manic episodes of bipolar disorder (n = 43), methamphetamine-induced psychotic disorder (n = 46), and control group (n = 47). Among 138 patients in acute psychotic episodes, 33 patients were in their first episode of psychosis, while 105 patients were in acute exacerbation of their chronic psychotic disorders. The Brief Psychiatric Rating Scale (BPRS) was measured by an expert attending psychiatrist for all patients. Then, serum levels of calcium, phosphorus, parathormone, vitamin D, and CRP were assessed in all study groups.

Results: Among our 185 study subjects, it was observed that individuals with higher education levels and those who were married had a lower prevalence of mental disorders. In all patient groups, the serum levels of CRP were significantly higher, and PTH levels were significantly lower than in the control group (p < 0.001). The serum levels of calcium, phosphorus, and vitamin D were not statistically significantly different between the patient and control groups of the study. In chronic psychotic patients, CRP levels were significantly higher (p < 0.031), and vitamin D levels were significantly lower (p < 0.044) compared to first-episode psychotic patients.

Conclusion: This study suggests that CRP levels are significantly higher and PHT level is significantly lower in acute psychotic patients. Moreover, vitamin D levels were significantly lower in chronic psychotic patients compared to first-episode psychotic patients.