Abstract
Vitamin B12 is an essential vitamin. Among its many functions is its crucial role as a coenzyme in a step of normal synthesis of myelin. Likewise, it is a vital coenzyme in the synthesis of neurotransmitters. Therefore, it is no surprise that vitamin B12 deficiency is linked to a spectrum of neuropsychiatric disorders. Most physicians can quickly pick up typical pernicious anemia, but very few remember the association of vitamin B12 with neuropsychiatric disorders. In this case report, the author presents his own experience of neuropsychiatric disorder (presenting as carpal tunnel syndrome along with anxiety) related to vitamin B12 deficiency with a strong recommendation to include vitamin B12 in the initial set of laboratory investigations suggested for patients over 40 years of age presenting with neuropsychiatric disorders.