Association of low vitamin B12 levels with depressive and schizophrenia spectrum disorders in child and adolescent psychiatric inpatients.

Folate and vitamin B₁₂ are associated with neurodevelopment and neurotransmitter synthesis and insufficiencies of these nutrients could be linked to psychiatric disorders in children and adolescents. To assess serum levels of folate and B₁₂ in child and adolescent psychiatric inpatients and examine possible links between these levels and different psychiatric disorders. Child and adolescent psychiatric inpatients admitted in a general hospital during a 3-year period were included for analysis. Folate and B₁₂ levels were measured when the subjects were admitted. Psychiatric diagnoses were made following DSM-5 criteria and grouped into categories. Logistic regression analysis was used to study the effects of socio-demographic variables as well as folate and B₁₂ levels, insufficiencies and deficits as possible predictors of outcome (psychiatric diagnostic category). 729 inpatients (60.6% female, mean age: 15.1 ± 2 years) were included. A total of 42.9% presented insufficient folate levels and 19.4% insufficient B₁₂ levels. Insufficient B₁₂ levels were associated with depressive disorders in the multivariate model (OR = 0.82, p = 0.002) as was female sex (OR = 1.65, p = 0.007). Moreover, low vitamin B₁₂ levels were linked to schizophrenia spectrum disorders (SSD, OR = 0.9982, p = 0.024). In contrast, higher folate (OR = 1.15, p < 0.001) and vitamin B₁₂ levels (1.0024, p = 0.002) as well as female sex (OR = 7.86, p < 0.001) were associated with eating disorders. Insufficient or low B₁₂ levels could help predict depressive and SSD respectively in child and adolescent psychiatric inpatients. Further study could help us better understand the impact of this insufficiency during the neurodevelopmental period and the potential benefits of nutritional interventions.