**10.6 Suicidal attempts due to vitamin D deficiency**

Significant lower levels of vitamin D are seen in patients with suicidal tendencies than both non-suicidal depressive patients and healthy control individuals. Deficiency of vitamin D was found in 58% of cases of all the reported cases of suicides, compared to around 30% cases found for the healthy controlled cases and the non-suicidal depressed patient cases [33–35].

Accumulating studies indicate that a dysregulated immune system could be a contributing factor to depression and possibly specifically to suicidal tendency. Direct evidence of causality comes both from animal models, where induction of peripheral inflammation is known to lead to depressive changes, and from the so-called cytokine-induced depression in humans, where treatment with interferons (IFN) of patients with hepatitis increases the risk for development of both depression and suicidal tendency [32]. Thus, an indirect proportional relationship between serum vitamin D concentration and inflammatory cytokines is seen to be established, i.e., the lower the vitamin, the higher are the levels of the inflammatory cytokines IL-6 and IL-1β in the blood. The future prospective must be seen to compare vitamin D levels between other groups of psychiatric patients and groups of patients with personality disorders [7, 34, 36].
