Vitamin B12 deficiency

Abstract

Cobalamin (Vitamin B12) has been linked to the pathophysiology of several neuropsychiatric conditions. A analysis of 19 patients (14 vegetarians) with vitamin B12 insufficiency revealed diverse behavioural symptoms, with the majority lacking severe haematological or neurological signs.

Cobalamin (Vitamin B12), an essential water-soluble vitamin, is needed for DNA synthesis during cell division.

It is also associated with the manufacture of neurotransmitters such as dopamine and serotonin, and has consequently been implicated in the aetiology of a number of neuropsychiatric illnesses.

2 In the past, a one-carbon hypothesis of schizophrenia was proposed, citing defective transmethylation as the cause of hazardous metabolite buildup. 3

Although several psychiatric signs of vitamin B12 deficiency have been identified, the notion that B12 deficiency causes psychiatric diseases is frequently neglected. Depression, apathy, irritability, dementia, catatonia, delirium, and hallucinations are some of the psychiatric symptoms of vitamin B12 insufficiency. 4,5 Higher vitamin B12 levels may be connected with a more favourable depression prognosis. 6 In a study of psychiatric inpatients, the prevalence of vitamin B12 insufficiency ranged from 4 to 6 percent. 7 Neuropsychiatric problems have been recorded in up to 28% of patients without any change in hematocrit levels or increase in red cell mean corpuscular volume (MCV); these indices are often the most frequently tested for B12 insufficiency. In such circumstances, a vitamin B12 level assessment is necessary.

Vitamin B12 insufficiency is due to inadequate consumption or absorption. It is produced by bacteria and is only found in animal-derived goods, such as meat, egg, and dairy, but not in plant-derived items. As a result of improved nutrition, vitamin B12 insufficiency is relatively uncommon in affluent nations, but widespread in developing nations. Particularly prominent among the Indian population, as certain segments of society adhere to a strict vegetarian diet. 8 In this case series, we describe the coexistence of vitamin B12 insufficiency and mental symptoms in 19 patients.

Case Sequence

A significant proportion of our clients were diagnosed with psychosis. All systemic evaluations were normal with the exception of three patients, one of whom had sensory impairments in both lower extremities and the other two of whom had pallor. Table 1 displays the clinical features of patients with serum B12 concentrations in the lower normal range.

The majority of psychotic patients exhibited substantial Schneiderian first-rank symptoms, including thought alienation phenomena, commenting and third-person auditory hallucinations, persecution and reference delusions, and passivity phenomena. Those with depression had typical depressive symptoms, including predominately depressive cognitions, anhedonia, fatigue, and physical symptoms. The patient suffering from episodic psychosis exhibited strong psychotic symptoms, but lacked conventional first-rank symptoms. The bipolar patient displayed classic manic symptoms.

Discussion

This paper emphasises the significance of assessing vitamin B12 levels in patients with psychiatric disorders. All patients presented with psychiatric symptoms alone, and vitamin B12 insufficiency was found only after further evaluation. Due to their vegetarian diet, B12 insufficiency was suspected in these individuals; fourteen of the 19 patients followed a rigorous vegetarian diet. A functional B12 shortage is frequent among vegetarians, as Vitamin B12 is absent from plant foods. 1 Due to the cross-sectional nature of our study, a cause–effect link cannot be drawn, and the association may be primary, secondary, or coincidental to the psychiatric condition. On the other hand, it has been reported that psychotic symptoms believed resistant to psychotropic therapies improved significantly after injection of vitamin B12. 4,9,10

Although cases of dementia-like symptoms have also been noted in the current literature, this is less likely to be the case in our cohort because the majority of these individuals were middle-aged. The majority of the elderly population at our institution would visit a separate Geriatric Psychiatry clinic.

On the basis of laboratory evaluations, Vitamin B12 insufficiency was found in the majority of patients without substantial haematological and neurological signs. On physical examination, pallor was absent in all but two patients. In a couple of the cases, B12 levels were below the lower limit of the normal range, lending validity to previous claims that psychiatric indications frequently precede neurological symptoms by many years. 11 Additionally, psychiatric manifestations can arise before vitamin B12 levels fall below 175 pg/L, and it has been suggested that the threshold should be raised to 660 pg/L. 11 Studies also identify a "window time" within which treatment may restore pathological alterations, beyond which they may be irreversible. 10

Mild vitamin B12 insufficiency may have been prevalent and undiscovered for extended periods of time in all mental patients, and it has now been recommended that these levels be measured.

8 The screening of individuals with psychiatric disease in high-risk groups, such as the elderly, vegetarians, and those with gastrointestinal illnesses, was advised in particular. 10 Serum B12 measurement is a straightforward and sensitive laboratory procedure, and a level above 600 pg/ml is recommended. 12 Additionally, it may be advisable to evaluate the B12 levels of non-vegetarian individuals who do not react to standard therapy.

However, there were sufficient clinical grounds to consider a primary B12 insufficiency in isolation despite the absence of comparable folic acid level assessment, which was not possible in our set-up due to logistical constraints.

Conclusions

The majority of patients in our series did not have any severe physical comorbidities known to be related with cobalamin deficiency, and the majority of them were vegetarians. Psychiatric patients who are vegetarians and who appear with symptoms unresponsive to traditional psychotropics or antidepressants must be viewed with a high degree of suspicion. Moreover, based on our observations, a syndromal psychotic disorder in vegetarian patients may need Vitamin B12 testing.

In conclusion, this paper highlights the significance of investigating vitamin B12 deficiency in psychiatrically sick individuals, particularly those in high-risk categories. Unknown as of yet are the changes that result from defective DNA synthesis and lead to the development of psychopathology. To further analyse the involvement of vitamin B12 in the aetiology of psychiatric diseases, additional research is required.

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