More B12 Psychosis

A case study of B12 deficiency from 2009 has been sitting in my “to read” folder and I finally got to it due to being confined to an airplane for a few hours today. The patient was a 31-year old Taiwanese male. Over the course of a few years he became more and more paranoid and schizophrenic until he was admitted due to alarming paranoid behavior. At first he was placed on an anti-psychotic drug. 7 weeks later, he was back in the hospital and this time it was discovered that he had been vegetarian since his teenage years with his only source of vitamin B12 being “minimal intake of dairy products.” The anti-psychotic drug was replaced with 1,000 µg per day of oral cobalamin. His state improved in 2 weeks and 1 year after discharge he had not had another episode. His B12 levels went from 136 to 227 pg/ml in the first 2 months of therapy.

Another more recent paper (2013) reported that of 19 patients demonstrating psychiatric illness at an Indian clinic, 14 had followed a “strict” vegetarian diet. Not many details were given, though 15 of the 19 patients had low B12 levels, defined as < 225 pg/ml.

I have no more papers on B12-deficient vegetarians in my “to read” folder. I hope it lasts for awhile…


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1. Kuo SC, Yeh CB, Yeh YW, Tzeng NS. Schizophrenia-like psychotic episode precipitated by cobalamin deficiency. Gen Hosp Psychiatry. 2009 Nov-Dec;31(6):586-8. | link

2. Jayaram N, Rao MG, Narasimha A, Raveendranathan D, Varambally S, Venkatasubramanian G, Gangadhar BN. Vitamin B₁₂ levels and psychiatric symptomatology: a case series. J Neuropsychiatry Clin Neurosci. 2013 Spring;25(2):150-2. | link

4 Responses to “More B12 Psychosis”

  1. Linda Says:

    Thank you for your informative posts – they are greatly appreciated!

  2. Dan Says:

    Thanks for sharing these case reports, Jack. I once had a B12 level of 104 pg/ml and yet was not psychotic at the time. I am wondering if low B12 level somehow unmasks an underlying tendency towards psychosis in certain vulnerable individuals – i.e. it is a sufficient but not necessary factor. There is far more low B12 in the population than there are chronic schizophrenics and psychotics – up to 25% of elderly people have below normal values of B12, yet psychosis in the elderly is not 1 in 4. This is why we are seeing “case” reports and not cohort studies on this phenomenon. Still, it does point out the connection between failure to replenish B12 on vegan diets and adverse neuropsychological consequences. The peripheral neuropathy manifestation of this disorder, due to subacute combined degeneration of the spinal cord, is also very significant.

  3. DJEB Says:

    I’m finding a disturbing number of combative, even threatening conspiracy hypothesists who are vegans. I can’t help thinking of B12-induced psychosis whenever I encounter these folks (which is too often for my tastes).

  4. Jack Norris RD Says:


    I seriously doubt it has anything to do with B12 deficiency in most cases.

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