A 21-year-old college student was referred to us by the counseling center at our university for a psychiatric evaluation after 11 psychotherapy sessions over 3 months had failed to reduce her feelings of anxiety and panic.
During our evaluation, the patient described feeling “not quite right” for many months. She had been experiencing mental fogginess, fatigue, and worsening concentration/ memory. Her anxiety, which had been gradually increasing, was the result of being unsure about her gait. She first noticed this while walking down some bleachers; she felt dizzy, was afraid of falling, and couldn’t walk down without assistance. All episodes of “panic” occurred in situations where she experienced disequilibrium, unsteady gait, and fear of falling. She grew fearful of driving or going anywhere without assistance.
The patient had celiac disease that was well controlled with a gluten-free diet. She had no personal or family psychiatric history and no history of substance abuse.
Physical exam and lab studies, including a complete blood count, comprehensive metabolic panel, and thyrotropin and folate levels, were normal. Her homocysteine level was 11.8 μmol/L (reference range, 5.4-11.9 μmol/L) and vitamin B12 level was 292 pg/mL (reference range, 200-1100 pg/mL). Her lab report included a note that read, “Although the reference range for vitamin B12 is 200 to 1100 pg/mL, it has been reported that between 5% and 10% of patients with values between 200 and 400 pg/mL may experience neuropsychiatric and hematologic abnormalities due to occult B12 deficiency; <1% of patients with values >400 pg/mL will have symptoms.”
Based on this vitamin B12 level, the patient’s symptoms, and her borderline high homocysteine level, we diagnosed vitamin B12 deficiency.
There are no recommendations by the US Preventive Services Task Force or any other major US medical society for routine vitamin B12 screening.1 In Canada, the Medical Services Commission of the British Columbia Ministry of Health recommends B12 screening for patients who present with macrocytic anemia or unexplained neurologic symptoms (eg, paresthesia, numbness, poor motor coordination, memory lapses, or cognitive or personality changes).2
Vitamin B12 deficiency can be caused by numerous conditions, including those that cause malabsorption (such as gastric bypass). It can also be caused by diseases such as human immunodeficiency virus infection or Crohn’s disease, long-term adherence to a vegetarian or vegan diet, or by any other lack of dietary intake.1 The condition can cause hematologic-related signs and symptoms such as megaloblastic anemia, fatigue, and syncope. It also can have neurologic manifestations, including paresthesia, weakness, motor disturbances (including gait abnormalities), vision loss, and a wide range of cognitive and behavioral changes.1 Anemia is uncommon because since 1998, the US Food and Drug Administration has required fortification of all enriched grain and cereal products with folic acid; thus, vitamin B12 deficiency may proceed without anemia revealing its presence.1
A controversial topic. Vitamin B12 deficiency is a complicated and controversial subject. Specifically, there is uncertainty about the clinical importance of lower serum levels of vitamin B12 (200-400 pg/mL), their impact on well-being, and the need for treatment. In addition to measuring a patient’s serum B12 level, testing a second biomarker (such as homocysteine or methylmalonic acid) can be helpful in establishing a diagnosis of B12 deficiency.1 Levels of each of these are elevated in patients with B12 deficiency.1
Although vitamin B12 deficiency has been well studied in older patients,3 little has been published about the condition in young adults. National Health and Nutrition Examination Survey (NHANES) data from 2000 to 2004 shows that almost 40% of people ages 19 to 30 years have a B12 level <400 pg/mL.1 How many of these individuals are at risk of complications of B12 deficiency is unknown.
B12 supplementation might improve depression, anxiety
B12 supplementation is inexpensive and has no significant adverse effects.1 It can be administered orally, parenterally (intramuscularly or subcutaneously), or intranasally.1 A common oral regimen is 1 mg/d; parental regimens vary widely, but might include a 1-mg injection once a week for 8 weeks, then once a month for life.1
Some evidence suggests B12 supplementation may improve symptoms of depression and anxiety. A Pakistani study randomized 73 patients with depression and “low normal” B12 levels (190-300 pg/mL) to an antidepressant only (equivalent to imipramine 100-250 mg/d or fluoxetine 20-40 mg/d) or an antidepressant plus parenteral B12 (1000 mcg once a week).4 At 3 months follow-up, 100% of the treatment group showed at least a 20% reduction in their Hamilton Depression Rating Scale (HAM-D) score, compared to 69% in the control arm (P<.001).4