Comparison of serum carnitine levels and clinical correlates between outpatients and acutely hospitalised individuals with bipolar disorder and schizophrenia: A cross-sectional study

Objectives: We sought to compare serum carnitine levels and clinical correlates between stable outpatients and acutely hospitalised individuals with diagnoses of bipolar disorder and schizophrenia.Methods: We obtained clinical information as well as serum levels for total and free carnitine, high-density lipoprotein (HDL) and triglycerides in 60 consenting individuals.Results: We found higher total serum carnitine levels in our outpatient group in comparison to acutely hospitalised psychiatric patients, with a statistically significant P value of 0.045. Metabolic syndrome was more prevalent in the outpatient (37.9%) versus inpatient group (16.1%). We identified significantly higher carnitine levels in patients who met the criteria for metabolic syndrome in comparison to the patients without metabolic syndrome, with respective P values for total and free carnitine of 0.0048 and 0.0029.Conclusions: This study revealed a complex relationship among carnitine metabolism, metabolic syndrome and behavioural outcomes. Future studies of carnitine metabolism in the context of mental illness as well as metabolic syndrome are warranted.