Psychiatric symptoms of Vitamin B12 deficiency can be wide-spread but also non-specific. In my practice I have seen several people who ultimately had a Vitamin B12 deficiency who presented with psychiatric symptoms, no signs of anemia (which is a common lab finding but is not necessarily always present) and who otherwise had been undiagnosed. It is especially important in geriatric patients with any early signs of cognitive decline since Vitamin B12 is a reversible medical cause of cognitive impairment. The following symptoms are important findings but keep in mind, most people present with a more subtle picture that is slow and progressive in nature. A few groups are especially at risk: Gastric bypass surgery history, long-history of antacid medications, Crohn’s history, Celiac disease and people who do not eat meat products. Some of the findings are outlined below:

Neurologic changes — Neurologic problems, when present, consist of the classic picture of subacute combined degeneration of the dorsal (posterior) and lateral spinal columns. This lesion, specific for Cbl deficiency, is due to a defect in myelin formation of unknown mechanism. The neuropathy is symmetrical and affects the legs more than the arms. It begins with paresthesias and ataxia associated with loss of vibration and position sense, and can progress to severe weakness, spasticity, clonus, paraplegia, and even fecal and urinary incontinence.

Other neurologic abnormalities that can be seen include cerebellar ataxia, axonal degeneration of peripheral nerves and central nervous system symptoms including memory loss, irritability, dementia, and extrapyramidal signs (such as tremors, rigid movement of limbs)
Of clinical importance, not all patients with neurologic abnormalities secondary to Cbl deficiency are either anemic or have macrocytic red cell indices. Therefore a lab finding of no anemia does not rule out a Vitamin B12 defiency.

Psychiatric changes-A multitude of psychiatric symptoms can occur which include: Memory/cognition changes or slowing, personality changes, general confusion, anxiety, new-onset mood symptoms or a combination of any of the above.

Often the most notable neuropsychiatric symptoms to emerge early are a mild balance problem such as heel-toe walking difficulty or a Romberg Sign (standing together with eyes closed and not being able to balance). These subtle balance issues can be present despite otherwise a relatively normal sense of movement. The balance issues often accompany cognitive slowing and increased anxiety.

Luckily blood tests exist which include testing for Vitamin B12 and Methylmalonic-acid which can confirm whether a B12 deficiency exists.