Abstract
The single infusion of ketamine, an N-methyl-d-aspartic acid (NMDA) glutamate receptor antagonist, exerts a therapeutic effect in
both unipolar and bipolar depression. Homocysteine (HCY) acts agonistically on the
NMDA receptor, hyperhomocysteinemia is related to depression, and folic acid and vitamin
B12 are associated with HCY system. We estimated the serum levels of these substances
in 20 bipolar depressed patients before ketamine infusion. 10 patients responded favorably
to this procedure, as their score on the Hamilton depression rating scale, compared
to baseline, was reduced by more than 50%, after 7 days. The vitamin B12 level was
significantly higher in “responders” compared to the remaining patients. No differences
between the 2 groups were found with regard to HCY, folic acid levels and such clinical
factors as age, duration of illness and duration of current episode. These preliminary
data suggest that the vitamin B12 level may be connected with the efficacy of ketamine
infusion in bipolar depression.
Key words
depression treatment - ketamine - vitamin B12 - homocysteine - folic acid