Psychiatric problems tied to vitamin B-12 deficiency

Psychiatric problems stemming from a deficiency of vitamin B-12appear to be more prevalent than commonly believed, researchers say.

"I think it's a lot more common than people had thought," saidDr. John Lindenbaum, a professor of medicine at theColumbia-Presbyterian Medical Center in New York.

Doctors had long known that a variety of mental problems rangingfrom minor memory lapses to severe psychotic behavior could be causedby a lack of the vitamin. Also known as cobalamin, the vitamin isnecessary for proper brain function, so a lack of the substancedisrupts normal brain activity.

The problem usually occurs in older people who develop digestiveproblems …