A deficiency in certain B vitamins can cause the psychiatric disorders of dementia and psychosis with symptoms including depression, a lack of self-control, paranoia, immodesty and hallucinations, according to Roger Simon, M.D., et al. in a 2009 article published in "Clinical Neurology." People who are malnourished are susceptible to developing these vitamin deficiencies and, therefore, the psychiatric disorders. Most of the people who develop Korsakoff's psychosis have a history of alcohol abuse, however.
A deficiency in vitamin B1, or thiamine, can cause Wernicke's syndrome, a condition in which people have abnormal eye movements, a lack of coordination and mental confusion. Most people with this disorder are alcoholics, according to Alan Ropper, M.D., in “Adams & Victor’s Principles of Neurology.” Korsakoff's syndrome is a psychiatric disorder that usually develops in alcoholics after Wernicke's but can develop in people who are malnourished or have brain damage. Most patients with Wernicke's have memory problems, especially with recent events, and make up stories to fill in the gaps, Dr. Ropper states.
B12 Dementia and Psychosis
A vitamin B12 deficiency can cause dementia and psychosis, as explained by Dr. Simon. The symptoms of dementia include various memory problems, not being able to concentrate and focus, and a difficulty with mathematical calculations. People with this vitamin deficiency have manic mood swings, where they are depressed or overconfident. They are quick to anger, impulsive, paranoid, and immodest in their dress or behavior. They may also hear voices and hallucinate.
Niacin is vitamin B3, and a deficiency in this vitamin can also lead to psychiatric disorders, explains Larry Johnson, M.D., Ph.D., attending physician at the Central Arkansas Veterans Healthcare System. People may become psychotic, have problems with their memory and create stories to fill in their gaps of memory loss, a phenomenon referred to as confabulation. They can become very confused and disoriented. Some may show signs of paranoia and depression, or become impulsive, extremely happy and full of self-importance.
Treatment for Wernicke's-Korsakoff's
In “Adams & Victor’s Principles of Neurology,” Dr. Ropper explains that Wernicke's is a medical emergency because people with this disorder need thiamine to prevent it from progressing to Korsakoff's psychosis and causing irreversible damage. They may need high doses of thiamine for several days. In addition, because the body uses thiamine to break down glucose, people who are alcoholics or malnourished are given thiamine before glucose if treated in the emergency department, to prevent precipitating Wernicke's. A long-term alcoholic can develop a deficiency in just seven to eight weeks.
Treatment for B12 and B3 Psychiatric Disorders
For people who do not have a severe deficiency of vitamin B12, they can take a daily dose of the supplement. In a severe deficiency, however, patients will need injections one to four times a week, then once a month. Dr. Johnson writes in “The Merck Manual for Healthcare Professionals,” that for most elderly people with dementia due to a B12 deficiency, the dementia does not improve. They will need B12 to correct the other effects of the deficiency, however. Those with a B3 deficiency can take niacin.