Table A4.

Depression.

Reduced transmitter formation—Rev [52]; also see Figure 3: Folic acid and SAM necessary for the synthesis of serotonin, noradrenaline and dopamine, both directly as well as via the synthesis of tetrahydrobiopterin. Significant changes in patients with depression: increase in HCys (plasma), decrease in folic acid (plasma, erythrocytes, liquor), SAM (liquor) and metabolites of the 3 transmitters (liquor)

Case control studies: Plasma HCys >10 μM → doubling the risk of depression [178]. Intake of vitamin B6, B12, folate correlates negatively with the occurrence of depression (12 years observation period) [179]. Intervention studies: The three B-vitamins versus placebo in patients at risk of depression for 7 years: significantly lower frequency [180]. Therapy with antidepressants in combination with folic acid, 5-methyl-tetrahydrofolate or SAM: better effect than antidepressants alone [52].

Brain tissue: no HCys transsulfuration and no re-methylation of HCys to methionine by betaine (cf. Section 2.1) high sensitivity to folic acid and vitamin B12 deficiency.