Homocysteine Levels in Patients with Schizophrenia on Clozapine Monotherapy

Abstract

We tested the hypothesis that homocysteine levels are higher in blood of schizophrenic subjects on clozapine monotherapy than in healthy controls and they correlate with anthropometric measurements, laboratory tests and results of bioimpedance analysis of body composition. Data for 24 subjects with schizophrenia treated with clozapine and 24 age- and sex-matched healthy volunteers was analyzed. Regarding the whole group, homocysteine levels were significantly higher in men (17.0 ± 3.4 vs. 12.1 ± 4.0 μmol/L, p = 0.009). Homocysteine levels correlated with waist circumference (R = 0.58, p = 0.003), waist-to-hip ratio (R = 0.57, p = 0.003), basal metabolic rate (R = 0.48, p = 0.01), lean body mass [kg] (R = 0.53, p = 0.008), body water [L] (R = 0.53, p = 0.008) and triglycerides (R = 0.57, p = 0.003). There were no significant differences of homocysteine levels for impaired fasting glucose, abdominal obesity, obesity/overweight, and dyslipidemia. Homocysteine levels did not correlate with age, treatment duration, clozapine dose, weight, body mass index, abdominal circumference, blood pressure, total body fat, cholesterol, high density lipoproteins, low density lipoproteins, uric acid, calcium, glucose, insulin, homoeostasis model assessment of insulin resistance 1, and homoeostasis model assessment of insulin resistance 2. We did not find significant differences in blood homocysteine levels between subjects with schizophrenia and controls. Association with waist circumference may support homocysteine role as an important cardiovascular risk factor. Association with lean weight may explain why men have higher levels of homocysteine than women.

Homocysteine levels in schizophrenia and affective disorders—focus on cognition

“…In turn, the cross-sectional study by Eren et al ( 2010 ) on chronic schizophrenia patients revealed significantly lower levels of plasma folate, but not Hcy or vitamin B12, in patients receiving higher doses of typical antipsychotics (chlorpromazine equivalent >400 mg). Another cross-sectional study revealed no significant difference in Hcy level between schizophrenia patients receiving clozapine in monotherapy and healthy controls (Wysokiński and Kłoszewska, 2013 ). There is also one study showing a positive relationship between Hcy levels and N-desmethyl-olanzapine concentration that is one of the main olanzapine metabolites (Lu et al, 2013 ).…”

Regulation of inflammatory pathways in schizophrenia: A comparative study with bipolar disorder and healthy controls

“…For homocysteine (Hcy), an intermediate amino acid containing a sulfhydryl radical that can act as an oxidant, the results are controversial. While some studies found higher levels of this oxidative stress biomarker in several subgroups of SCH (31-33) compared with HC patients (31,34), others did not (35,36).…”

Folic acid, vitamin B12 and homocysteine levels following olanzapine administration in schizophrenia patients

“…chlorpromazine 400 mg. 14 The findings of above two studies does not conform to the present study as because in the present study the patients were not folic acid, vitamin B12 deficient, especially folic acid levels were significantly higher in schizophrenia patients before and after olanzapine treatment compared to those in the controls. Another cross-sectional study by Wysokinski and Kioszewska (2013) 21 shows that no significant differences were found in serum homocysteine levels between healthy controls and schizophrenia patients who received clozapine monotherapy. So, we can say that differences in lifestyle between the study groups may account for differences in folate and vitamin B12 levels and also the different methodologies of homocysteine, folate and vitamin B12 assessment and genotypic differences in the samples studied could also be possible factors for the inconsistencies in results.…”