A controlled trial of methylene blue in severe depressive illness. - PubMed - NCBI
Methylene blue, 15 mg/day, was compared with placebo in treatment of severe depressive illness. The 3-week trial was designed to avoid bias by placebo response and also to avoid observer bias. Improvement in patients receiving methylene blue was significantly greater than in those receiving placebo. Methylene blue at a dose of 15 mg/day appears to be a potent antidepressant, and further clinical evaluation is essential.
I'll summarize some details of the study since the full text isn't free:
- The results were from 31 women who completed the trial. They were considered physically healthy.
- "Patients who received placebo showed little or no evidence of improvement during the 3- week period. In contrast, patients receiving methylene blue showed marked improvement, which was significantly greater than that of the placebo group at 7 days on the Beck Self-Rating Inventory (p < 0.01), at 14 days on the Montgomery-Asberg Scale (p < 0.01), and on all 4 scales (Beck, Hamilton, Montgomery-Asberg. and global) by 21 days..."
- Eyeballing the data, several of the parameters appeared to be continually improving rather than leveling off, so I suspect a longer trial would've had even better effects.
- The authors reference this study using 300mg/day methylene blue for manic-depressive psychosis.