...Depression is well known to be associated with altered anti- and prooxidant profiles, Vit C may play antidepressant function also by its antioxidant properties [
118,
119].
The available literature data indicate that Vit C deficiency is very common in patients with depressive disorders. Gariballa [
169] in a randomized, double blind, placebo-controlled trial observed that low Vit C status was associated with increased depression symptoms following acute illness in older people.
...Parameters were measured at baseline as well as after 6 weeks and 6 months. Patients with Vit C depletion had significantly increased symptoms of depression as compared to those with its higher concentrations both at baseline and at 6 weeks. Significantly lower serum Vit C level in patients with depression vs. healthy controls was also shown by Bajpai et al. [
170] and Gautam et al. [
171]. Moreover, in the latter study
dietary supplementation of Vit C (1000 mg/day) along with vitamins A and E for a period of 6 weeks resulted in a significant reduction in depression scores [
171].
Furthermore, a case-control study carried out on 60 male university students showed that subjects diagnosed with depression had significantly lower intake of Vit C than the healthy ones [
172].
Similarly, in another case-control study involving 116 girls identified as having depressive symptoms, depression was negatively associated with Vit C intake, even after adjusting for confounding variables [
173].
Rubio-López et al. [
174], in turn, examined the relationship between nutritional intake and depressive symptoms in 710 Valencian schoolchildren aged 6–9 years and also observed that nutrient intake of Vit C was significantly lower in children with depressive symptoms. Additionally, prevalence of Vit C inadequacy (below dietary recommended intakes) was significantly higher in subjects with depressive symptoms.
The efficacy of Vit C as an adjuvant agent in the treatment of pediatric major depressive disorder in a double-blind, placebo-controlled pilot trial was evaluated by Amr et al. [
175]. Patients (
n = 12) treated for six months with fluoxetine (10–20 mg/day) and Vit C (1000 mg/day) showed a significant decrease in depressive symptoms in comparison with the fluoxetine plus placebo group as measured by the Children’s Depression Rating Scale and Children’s Depression Inventory. No serious adverse effects were shown.
Zhang et al. [
176] in double-blind clinical trial investigated the effect of Vit C (500 mg twice daily) on mood in non-depressed acutely hospitalized patients. The applied therapy increased plasma and mononuclear leukocyte Vit C concentrations and was associated with a 34% reduction in mood disturbance (assessed with Profile of Mood States) [
176].
Similarly, Wang et al. found that short-term Vit C (500 mg twice daily) treatment was associated with a 71% reduction in mood disturbance (assessed with Profile of Mood States) and a 51% reduction in psychological distress (assessed with Distress Thermometer) in acutely hospitalized patients with a high prevalence of hypovitaminosis C [
177].
Khajehnasiri et al. [
178] in a randomized, double-blind, placebo-controlled trial involving 136 depressed male shift workers observed, in turn, that Vit C administration (250 mg twice daily for 2 months) alone and in combination with omega-3 fatty acids significantly reduced the Beck Depression Inventory (BDI) score, however omega-3 fatty acid supplementation alone was more effective. Moreover, Vit C and omega-3 fatty acids supplementation alone (but not in combination) decreased significantly serum MDA levels...
