The prevalence of vitamin B12 and folate deficiency is significant in the psychiatric population. These deficiencies may be associated with varied neuropsychiatric signs and symptoms, caused by different pathophysiological mechanisms.

Characterize the main neuropsychiatric signs and symptoms associated with vitamin B12 and folate deficiencies. Evaluate the prevalence of these vitamins deficiencies in an acute inpatient psychiatric department, dedicated to Affective Disorders.

To review the clinical significance of vitamin B12 and folate deficiencies in psychiatric disorders and reflect on the importance of routine screening in mental health care.

Observational, retrospective and descriptive study, with analysis of clinical and blood tests data concerning the total number of inpatient episodes in 2015. Non-systematic review of the scientific literature.

A small case series of the patients that had folate or B12 deficiency detected is presented. The prevalence of vitamin B12 and folate deficiencies found in our study is in accordance with the data found in the literature.

Vitamin B12 and folate deficiencies should be considered in the approach to the psychiatric patient as its neuropsychiatric manifestations are varied, can be severe, and may constitute a potentially treatable cause of mental disorder. Our data shows that folate and B12 deficiencies are significant in inpatients and we believe it justifies routine screening at admission.

The authors have not supplied their declaration of competing interest.