Methylcobalmin, is the best treatment as well as dietary supplement for the people who cannot absorb vitamin B12 and / or suffers from its deficiencies.
Folate, vitamins B9 and B12 also work together to produce natural S-adenosylmethionine (SAMe), a compound involved in immune function and mood.
Vitamin B12 Supplementation: Preventing Onset and Improving Prognosis of Depression
Higher intakes of both Vitamins B12 and B6 reduced depressive symptoms over time.