INCREASED PLASMA SERINE CONCENTRATIONS IN DEPRESSION

Recently, it has been shown that higher plasma serine concentrations a re a possible biological marker for psychoses including schizophrenia. The present study was carried out in order to investigate plasma seri ne levels in 123 depressed subjects (41 minor; 47 simple major; 35 mel ancholic depressives) and 50 normal controls. It was found that plasma serine concentrations were significantly higher in depressed subjects than in normal controls. There were no significant correlations betwe en plasma serine and postdexamethasone cortisol values. Dexamethasone administration had a significant suppressive effect on plasma serine l evels in depression but not in normal controls. In the latter - but no t in depressed subjects - there were significant positive correlations between plasma serine and L-tryptophan concentrations.