Serum folate, vitamin B12, and homocysteine in major depressive disorder, Part 2: predictors of relapse during the continuation phase of pharmacotherapy.
OBJECTIVE
In the present study, we assessed the relationship between serum folate, vitamin B12, and homocysteine levels on the rate of relapse in outpatients with remitted major depressive disorder (MDD) during a 28-week continuation phase of treatment with fluoxetine.


METHODS
Seventy-one outpatients (mean +/- SD age = 40.2 +/- 11.1 years; 56.3% women) with MDD (as assessed with the Structured Clinical Interview for DSM-III-R) who had remitted and who were enrolled in the continuation phase of treatment with fluoxetine had serum folate, vitamin B12, and homocysteine measurements completed at baseline (prior to acute-phase treatment). Patients were followed for 28 weeks of continued treatment with fluoxetine 40 mg/day to monitor for depressive relapse. Folate levels were classified as either low (< or = 2.5 ng/mL) or normal. Vitamin B12 levels were classified as either low (< or = 200 pg/mL) or normal. Homocysteine levels were classified as either elevated (> or = 13.2 micromol/L) or normal. With the use of separate logistic regressions, we then assessed the relationship between folate, vitamin B12, and homocysteine level status and relapse. The study was conducted from November 1992 to January 1999.


RESULTS
The presence of low serum folate levels (p =.004), but not low B12 (p >.05) or elevated homocysteine levels (p >.05), was associated with relapse during continuation treatment with fluoxetine. The relapse rates for patients with (N = 7) and without (N = 64) low folate levels were 42.9% versus 3.2%, respectively.


CONCLUSIONS
Low serum folate levels were found to place patients with remitted MDD at risk for depressive relapse during the continuation phase of treatment with fluoxetine.
Papakostas
George I
GI
Depression Clinical and Research Program, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. gpapakostas@partners.org
Petersen
Timothy
T
Mischoulon
David
D
Green
Cassandra H
CH
Nierenberg
Andrew A
AA
Bottiglieri
Teodoro
T
Rosenbaum
Jerrold F
JF
Alpert
Jonathan E
JE
Fava
Maurizio
M
D000328:Adult; D000553:Ambulatory Care; D003866:Depressive Disorder / Q000097:blood* / Q000175:diagnosis / Q000188:drug therapy*; D004334:Drug Administration Schedule; D005260:Female; D005473:Fluoxetine / Q000008:administration & dosage / Q000627:therapeutic use*; D005492:Folic Acid / Q000097:blood*; D005500:Follow-Up Studies; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D011336:Probability; D011569:Psychiatric Status Rating Scales; D012008:Recurrence; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D016896:Treatment Outcome; D014805:Vitamin B 12 / Q000097:blood*
D005473:Fluoxetine; D005492:Folic Acid; D006710:Homocysteine; D017367:Selective Serotonin Reuptake Inhibitors; D014805:Vitamin B 12