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adjunctive treatment for SSRI-resistent depression” even in the absence of baseline
folate deficiency.^12
The Natural Standard rates folate for depression as “C,” “unclear scientific evidence
for this use.” The Natural Standard rates folate as “A,” “strong scientific evidence for
this use,” only for folate deficiency and related anemia. As to depression, the Natural
Standard states only that folic acid deficiency has been found among people with
depression and has been linked to poor response to antidepressants. Although the
Natural Standard concedes that folate has been used adjunctively, for enhancing
treatment response to antidepressants, it does not credit the evidence in its rating. The
Natural Standard states that folate is “not effective” as a replacement for
antidepressants, but it does not comment on adjunctive use.
Berkeley Wellness does not discuss any effect of folate on depression, focusing instead
on dementia, for which it reports contradictory findings.
Notwithstanding the promising studies and the 2007 meta-analysis and 2009 review,
Mischoulon and Rosenbaum conclude that the data are still too preliminary to
recommend consumer action beyond supplementation of folate deficiencies at this
point. They suggest that assessment of folate status ought to be included in any
comprehensive medical workup for depression and that folate replacement is essential
for individuals with conditions leading to folate deficiency, such as alcoholism, metabolic
problems, and malabsorption. They add that blood tests for folate may not be enough,
that SAM-e and homocysteine levels may be as important, and that genetics (the
common mutations of the MTHFR enzyme gene discussed above) also must be
evaluated.
Lake and Spiegel observe that the proportion of folate deficiency “appears to correlate
with the severity of psychiatric symptoms. Even among individuals with normal folate
levels, higher folate levels are correlated with less severe depression, higher age at
onset,”^13 and improved response to antidepressants.
The Mayo Clinic is also positive, giving folate a green light as a supplement, but without
any discussion of potential use for depression or cognition.