Featured article | September 2025
Exploring neuropsychiatric manifestations of vitamin B complex deficiencies
Anamaria Han et al., Front. Psychiatry 16:1569826. doi: 10.3389/fpsyt.2025.1569826
This review article explores in detail how deficiencies in the B vitamin complex contribute to a wide range of neuropsychiatric symptoms.
Discussed in this article:
- Key roles of each B vitamin in brain and mental health.
- Links between deficiencies and psychiatric symptoms such as depression, anxiety, irritability, psychosis, and cognitive impairment.
- Mechanisms including neurotransmitter imbalance, homocysteine elevation, mitochondrial dysfunction, and impaired myelination.
- Risk factors for deficiencies (poor diet, alcoholism, chronic illness, certain medications).
- The potential for misdiagnosis of psychiatric conditions when the underlying issue is a B-vitamin deficiency.
- The importance of screening and supplementation as part of psychiatric and neurological care.
Discussed deficiencies and mental health:
- Vitamin B1 (Thiamine)
- Deficiency can cause irritability, confusion, apathy, memory impairment, and depression.
- Severe deficiency (Wernicke–Korsakoff syndrome) is linked to hallucinations, psychosis, and profound cognitive dysfunction.
- Vitamin B2 (Riboflavin)
- Low levels may contribute to fatigue, depression, and irritability.
- Deficiency is associated with impaired energy metabolism in the brain, which can worsen mood and cognitive symptoms.
- Vitamin B3 (Niacin)
- Severe deficiency (pellagra) manifests with the “three Ds”: dermatitis, diarrhea, and dementia, where the dementia component includes depression, apathy, irritability, poor concentration, and psychosis.
- Even milder insufficiency can contribute to low mood and cognitive slowing.
- Vitamin B6 (Pyridoxine)
- Deficiency disrupts neurotransmitter synthesis (serotonin, dopamine, GABA), leading to depression, anxiety, irritability, confusion, and in severe cases, seizures.
- Psychiatric symptoms are sometimes the earliest manifestations of B6 deficiency.
- Vitamin B9 (Folate)
- Folate deficiency is strongly linked with major depression, cognitive decline, dementia, and schizophrenia-like symptoms.
- Low folate can elevate homocysteine, contributing to neurotoxicity and mood disorders.
- Often implicated in treatment-resistant depression.
- Vitamin B12 (Cobalamin)
- Deficiency can cause depression, irritability, memory impairment, and cognitive decline progressing to dementia.
- Severe deficiency may lead to psychosis, paranoia, hallucinations, and personality changes.
- Neurological and psychiatric signs often appear before anemia develops.
Given the high prevalence of B vitamin deficiencies in specific populations, such as the elderly and those with restrictive diets, there is a pressing need for heightened clinical awareness and early intervention.
