No clear potentiation of antidepressant medication effects by folic acid+vitamin B12 in a large community sample.
BACKGROUND
Observational studies link low folate levels to depressive symptoms and to poor antidepressant medication response. Evidence supports a role for folate in potentiating the effect of antidepressant medications.


OBJECTIVE
This prospective study examines the effects of folic acid+vitamin B12 supplementation and antidepressant medication in a community-based study of older adults with depressive symptoms.


METHODS
A randomised controlled trial investigated the effectiveness of a medicinal and two behavioural preventive interventions over a two year period. The medicinal intervention compared dietary supplementation of 400 mcg/d folic acid+100 mcg/d vitamin B12 to placebo. Self reported use of antidepressant medication over two years was recorded. Participants were screened for psychological distress using the Kessler Distress 10-Scale (K-10; >15 eligible) and the main outcome measure was change in depressive symptoms on the Patient Health Questionnaire-9 (PHQ-9) at six weeks, six, 12 and 24 months. Nine hundred adults aged 60-74 years were included in the analysis, of whom 209 (23.2%) reported antidepressant use during the follow-up period.


RESULTS
A mixed model repeated measures analysis of variance for reduction in depressive symptoms found no significant three-way interaction between supplement group and antidepressant use over time on the PHQ-9 [F4, 825.1=0.32, p=0.87]. A small interaction between supplement group and antidepressant use over time was found for K-10 scores (F4, 799.5=2.50, p=0.0414).


CONCLUSIONS
There was little evidence for the potentiation of antidepressant medication by folic acid+B12 supplementation on depressive symptomatology. Further research should examine whether effects might be found at higher folic acid dosages or among clinical populations.
Christensen
Helen
H
Centre for Mental Health Research, Australian National University, Canberra, Australia. Helen.Christensen@anu.edu.au
Aiken
Alexandra
A
Batterham
Philip J
PJ
Walker
Janine
J
Mackinnon
Andrew J
AJ
Fenech
Michael
M
Hickie
Ian B
IB
D000368:Aged; D000928:Antidepressive Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D003866:Depressive Disorder / Q000188:drug therapy*; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014805:Vitamin B 12 / Q000008:administration & dosage / Q000627:therapeutic use*; D014815:Vitamins / Q000009:adverse effects / Q000627:therapeutic use*
D000928:Antidepressive Agents; D014815:Vitamins; D005492:Folic Acid; D014805:Vitamin B 12