Blood folate, vitamin B-12, and their relationships with cerebrospinal fluid monoamine metabolites, depression, and personality in suicide attempters

High prevalences of folate deficiency have been reported in psychiatric pat ients, and low folate and vitamin B-12 concentrations have been associated with depression and low levels of the serotonin metabolite 5-hydroxyindolea cetic acid (5-HIAA) in cerebrospinal fluid (CSF). A total of 107 suicide at tempters, 41 with information on CSF monoamine metabolite levels, were stud ied for the purpose of exploring the blood folate and serum B-12 levels and their relationships with the three major monoamine metabolites in the CSF, plasma cortisol before and after dexamethasone administration, the Beck Ho pelessness Scale (BHS), the Montgomery-Asberg Depression Rating Scale (MADR S), suicidality as measured with the Suicide Assessment Scale (SAS), and th e Marke-Nyman Temperament (MNT) dimensions. Diagnoses were made on the basi s of the DSM-III-R. Few patients had low folate or B-12 levels. No signific ant differences appeared between the diagnostic groups. B-12 correlated pos itively and significantly with cortisol (rsp = 0.23, P = 0.04). The monoami ne metabolites did not correlate significantly with folate or B-12. After a djustments for age, neither folate nor B-12 correlated significantly with t he BHS, MADRS, SAS, or MNT scores or post-dexamethasone cortisol levels. In suicide attempters without folate or B-12 deficiency, blood folate and ser um B-12 showed no relationship with depression or low CSF 5-HIAA concentrat ions. We could not replicate the high prevalences of folate or B-12 deficie ncy previously reported for psychiatric patients. Possible reasons for the negative findings are discussed.