Abstract
Mood disorders have been identified by the World Health Organisation (WHO) as the leading cause of disability worldwide. In New Zealand, there is a lifetime prevalence of 20% for mood disorders, with Māori and Pacific populations, as well as those from low-socioeconomic households experiencing a higher proportion of disorder (Oakley Browne et al., 2006). There is increasing evidence indicating inflammation and oxidative stress as a contributing factor to the pathophysiology of mood disorders such as major depressive disorder and bipolar disorder. This study investigated antioxidant vitamin C status in participants with mood disorders (n=66) as a biomarker study nested within a randomised control trial. Participants received either Interpersonal and Social Rhythm Therapy (IPSRT) alone, or IPSRT combined with Cognitive Remediation. Plasma vitamin C and urate concentrations were determined at baseline and 12-month follow-up by high performance liquid chromatography (HPLC). A healthy control population (n=18) was used for further comparison. This study found that the mood disorder cohort had significantly lower plasma vitamin C concentrations and higher urate concentrations at baseline compared to the healthy control population. In the mood disorder cohort, 35% had inadequate plasma vitamin C concentrations at baseline compared to 17% of the healthy control cohort. There was no significant difference in plasma vitamin C concentrations between baseline and follow-up for either treatment group or healthy controls. No correlation was found between plasma vitamin C concentrations and clinical measure for mood disorders including the Quick Inventory of Depressive Symptoms (QIDS) and Young Mania Rating Scale (YMRS). No correlation was found between plasma vitamin C concentrations and measures of cognitive function including the Cognitive Complaints in Bipolar Disorder Rating Assessment (COBRA) and Functioning Assessment Short Test (FAST). This research indicated the need for nursing education of patients with mood disorder around healthy diet and supplementation of vitamin C if required. Further research is needed to elucidate the relationship between vitamin C and mood disorders and to investigate the potential effects of supplementation on mood disorder symptoms.