A randomized controlled trial of Vitamin D supplementation in Iranian patients with schizophrenia: Effects on serum levels of glycogen synthase kinase‐3β and symptom severity

• Published in: International journal of psychiatry in medicine Vol. 58; no. 6; pp. 559 - 575
• Main Authors: Kalejahi, Parinaz, Kheirouri, Sorayya, Noorazar, Seyed Gholamreza
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.11.2023; Sage Publications Ltd
• Subjects: Insulin resistance; Schizophrenia; Vitamin D; Vitamin deficiency; severity; GSK-3β; schizophrenia; vitamin D supplementation; insulin resistance
• ISSN: 0091-2174; 1541-3527
• DOI: 10.1177/00912174231193303

Background Growing evidence has shown that hypovitaminosis D is a risk factor for developing schizophrenia and comorbid conditions. Therefore, this study aimed to examine the effect of vitamin D supplementation on serum levels of vitamin D, metabolic factors related to insulin resistance (IR) and the severity of the disorder in patients with schizophrenia. Methods Forty-eight chronic male patients with schizophrenia with vitamin D deficiency (≤20 ng/mL= (≤50 nmol/l) were selected and randomly assigned to vitamin D treatment and placebo groups. Subjects were supplemented for 8 weeks with vitamin D (2000 IU/day) or placebo. Results Within-group comparison revealed that the vitamin D group had a significant reduction in waist circumference, Positive and Negative Syndrome Scale – total score (PANSS-TS), and glycogen synthase kinase 3 beta (GSK-3β) levels (P = .022, P = <.001 and P = .013, respectively). On the other hand, the placebo group showed a significant increase in the level of fasting serum insulin and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) (P = .003 and P = .003). The between-group comparison showed a significant difference in terms of PANSS-TS, GSK-3β, fasting serum insulin (FSI), and HOMA-IR (P = .022, P = .048, P = .013 and P = .014 respectively). Conclusions Among vitamin D deficient patients with schizophrenia, vitamin D supplementation may affect GSK-3 β, an important biomarker in schizophrenia and insulin resistance. In addition, vitamin D supplementation in such patients may reduce the disorder’s symptom severity.