The association between vitamin D and symptom domains in psychotic disorders: A systematic review

Impact of body mass index elevation, Vitamin D receptor polymorphisms and antipsychotics on the risk of Vitamin D deficiency in schizophrenia patients

Antipsychotics with weight gain as side effect and vitamin D receptor dysfunction associated with single nucleotide polymorphisms (VDR SNPs) may have different effects on vitamin D status. Hence, present study aimed to investigate the relationship between vitamin D with body mass index (BMI), antipsychotics and VDR SNPs (rs2228570, rs1544410, rs7975232 and rs731236) in Malaysian patients with schizophrenia. Serum vitamin D level was measured using competitive enzyme-linked immunosorbent assay kit. VDR SNPs were analyzed using polymerase chain reaction-restriction fragment length polymorphism. We found significantly lower serum vitamin D level in patients with schizophrenia (p < 0.01), especially those taking atypical antipsychotics (p = 0.02) and combined antipsychotics (p = 0.02) and obese (BMI ≥27.5 kg/m2) patients (p = 0.04) after adjustment for covariates. For VDR SNPs, the CT genotype of rs1544410, CA genotype of rs7975232, and AA and AG genotypes of rs731236 may contribute to the significant decreased serum vitamin D level in patients (p < 0.05). Nevertheless, these relationships may differ by populations or medical conditions. The hypotheses of volumetric dilution and sequestration of vitamin D may explain the lower vitamin D level in obese patients. In addition, lifestyle factors such as poor diet and lack of physical activity with less sunlight exposure may cause reduced vitamin D level among patients. As patients in present study were prescribed with various antipsychotics, the effect of each antipsychotic on vitamin D level could not be determined. Thus, future studies should investigate the effect of different types of antipsychotics and obesity on vitamin D level in schizophrenia.

The prevalence of vitamin D deficiency and associated factors in first-episode psychosis

AIM

Vitamin D deficiency is prevalent in people with established psychotic disorders, but less is known about vitamin D levels in people with first-episode psychosis (FEP). This study aimed to determine the prevalence of vitamin D deficiency in people with FEP and identify the factors associated with vitamin D status.

METHODS

This was a prospective cohort study nested within a randomized controlled trial, which included 37 young people with an FEP with minimal antipsychotic medication exposure.

RESULTS

Twenty-four percent of participants were vitamin D deficient, and a further 30% were vitamin D insufficient. There was no association between vitamin D and demographic factors or clinical symptoms (positive, negative, general psychopathology and depressive symptoms) or cognition and functioning. However, vitamin D levels were associated with season of sampling.

CONCLUSIONS

Considering the longer-term adverse effects associated with vitamin D deficiency, it is warranted to ensure this clinical population receives supplementation if indicated.

Diminished social motivation in early psychosis is associated with polygenic liability for low vitamin D

Insufficiency of vitamin D levels often occur in individuals with schizophrenia and first-episode psychosis (FEP). However, it is unknown whether this represents a biological predisposition, or it is essentially driven by illness-related alterations in lifestyle habits. Lower vitamin D has also been associated with adverse neurodevelopmental outcomes and predominant negative psychotic symptoms. This study aimed to investigate the contribution of polygenic risk score for circulating 25-hydroxyvitamin D concentration (PRS-vitD) to symptom presentation among individuals with FEP enrolled in the Athens First-Episode Psychosis Research Study (AthensFEP n = 205) and the Psychosis Incident Cohort Outcome Study (PICOS n = 123). The severity of psychopathology was evaluated using the Positive and Negative Syndrome Scale at baseline and follow-up assessments (AthensFEP: 4-weeks follow-up, PICOS: 1-year follow-up). Premorbid intelligence and adjustment domains were also examined as proxy measures of neurodevelopmental deviations. An inverse association between PRS-vitD and severity of negative symptoms, in particular lack of social motivation, was detected in the AthensFEP at baseline (adjusted R2 = 0.04, p < 0.001) and follow-up (adjusted R2 = 0.03, p < 0.01). The above observation was independently validated in PICOS at follow-up (adjusted R2 = 0.06, p < 0.01). No evidence emerged for a relationship between PRS-vitD and premorbid measures of intelligence and adjustment, likely not supporting an impact of lower PRS-vitD on developmental trajectories related to psychotic illness. These findings suggest that polygenic vulnerability to reduced vitamin D impairs motivation and social interaction in individuals with FEP, thereby interventions that encourage outdoor activities and social engagement in this patient group might attenuate enduring negative symptoms.

Genome-wide Association Analysis of Schizophrenia and Vitamin D Levels Shows Shared Genetic Architecture and Identifies Novel Risk Loci

Low vitamin D (vitD) levels have been consistently reported in schizophrenia (SCZ) suggesting a role in the etiopathology. However, little is known about the role of underlying shared genetic mechanisms. We applied a conditional/conjunctional false discovery rate approach (FDR) on large, nonoverlapping genome-wide association studies for SCZ (N cases = 53 386, N controls = 77 258) and vitD serum concentration (N = 417 580) to evaluate shared common genetic variants. The identified genomic loci were characterized using functional analyses and biological repositories. We observed cross-trait SNP enrichment in SCZ conditioned on vitD and vice versa, demonstrating shared genetic architecture. Applying the conjunctional FDR approach, we identified 72 loci jointly associated with SCZ and vitD at conjunctional FDR < 0.05. Among the 72 shared loci, 40 loci have not previously been reported for vitD, and 9 were novel for SCZ. Further, 64% had discordant effects on SCZ-risk and vitD levels. A mixture of shared variants with concordant and discordant effects with a predominance of discordant effects was in line with weak negative genetic correlation (rg = -0.085). Our results displayed shared genetic architecture between SCZ and vitD with mixed effect directions, suggesting overlapping biological pathways. Shared genetic variants with complex overlapping mechanisms may contribute to the coexistence of SCZ and vitD deficiency and influence the clinical picture.

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.

Nanosystems for Brain Targeting of Antipsychotic Drugs: An Update on the Most Promising Nanocarriers for Increased Bioavailability and Therapeutic Efficacy

Orally administered antipsychotic drugs are the first-line treatment for psychotic disorders, such as schizophrenia and bipolar disorder. Nevertheless, adverse drug reactions jeopardize clinical outcomes, resulting in patient non-compliance. The design formulation strategies for enhancing brain drug delivery has been a major challenge, mainly due to the restrictive properties of the blood-brain barrier. However, recent pharmacokinetic and pharmacodynamic in vivo assays confirmed the advantage of the intranasal route when compared to oral and intravenous administration, as it allows direct nose-to-brain drug transport via neuronal pathways, reducing systemic side effects and maximizing therapeutic outcomes. In addition, the incorporation of antipsychotic drugs into nanosystems such as polymeric nanoparticles, polymeric mixed micelles, solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions, nanoemulgels, nanosuspensions, niosomes and spanlastics, has proven to be quite promising. The developed nanosystems, having a small and homogeneous particle size (ideal for nose-to-brain delivery), high encapsulation efficiency and good stability, resulted in improved brain bioavailability and therapeutic-like effects in animal models. Hence, although it is essential to continue research in this field, the intranasal delivery of nanosystems for the treatment of schizophrenia, bipolar disorder and other related disorders has proven to be quite promising, opening a path for future therapies with higher efficacy.

A preliminary investigation of the clinical and cognitive correlates of circulating vitamin D in bipolar disorder

The role that vitamin D plays in the cognitive and clinical characteristics of bipolar disorder (BD) is unclear. We examined differences in the levels and deficiency status of vitamin D in an Australian sample of BD patients compared to healthy controls; and determined the extent to which vitamin D is associated with clinical variables and cognitive function in the sample. 22 healthy controls and 55 stable outpatients with a diagnosis of BD and low-grade mood symptomatology provided a sample of blood and completed cognitive tests and clinical measures. Plasma concentrations of 25-hydroxyvitamin D (vitamin D) were assayed and used to segregate participants into subgroups with sufficient or deficient levels of vitamin D. Subgroups were then compared in terms of global cognition and a range of sociodemographic and clinical factors (number of past mood episodes, illness duration, seasonal mood pattern, mood symptom severity), while mean levels of vitamin D were compared between patients and controls. Although almost 27% of the current sample were vitamin D deficient, no significant differences in mean vitamin D levels or the prevalence of vitamin D deficiency were evident between BD patients and controls. Vitamin D was not associated with global cognition in either patients or controls, nor any of the clinical measures assessed in the study. In conclusion, we observed no difference in the vitamin D levels and deficiency status of an Australian sample of healthy individuals and BD patients with low grade mood symptomatology compared to controls. Clinical symptoms and global cognition also appear to be independent of vitamin D levels in BD.