Veganism and Mental Illness

Adam Lanza is the infamous mass murderer who killed 27 children and school staff members in Connecticut after committing matricide. A family friend said that Lanza was a vegan because he didn’t want to hurt animals. Apparently the shooter forgot that humans are also considered animals – specifically, primates and mammals. The story was published on Salon: Adam Lanza was a Vegan. Since very few vegans go on to commit murder, Lanza probably had other brain abnormalities. I’m mainly upset with celebrities and health writers embracing veganism as a trendy fad while glossing over the dangers of vegan diets.

Veganism is associated with vitamin B12 deficiency and inadequate intake of omega-3 fatty acids. Multiple studies across three decades among different populations have illustrated the link between veganism and cobalamin deficiency. Both vitamin B12 and omega-3 fats are important to brain function. Vegans risk developing mental illness if they avoid sources of B vitamins and omega-3s. There are case reports as well as larger studies that describe the vitamin B12 deficiency caused by vegan diets. When I was a vegetarian (not even a vegan) I started developing 15 out of 16 symptoms on this list of bipolar symptoms. I also experienced obsessive-compulsive symptoms.

People who are vegans for ethical reasons or who don’t like the taste of meat can still eat bivalve molluscs like clams and scallops or take krill oil supplements.


Abnormal fatty acid composition in the frontopolar cortex of patients with affective disorders. (Link)

Altered red cell membrane compositions related to functional vitamin B(12) deficiency manifested by elevated urine methylmalonic acid concentrations in patients with schizophrenia. (Link)

Assessment of fatty acid intakes in vegans and omnivores. (Link)

Augmentation of antidepressants with unsaturated fatty acids omega-3 in drug-resistant depression. (Link)

B-vitamin status and concentrations of homocysteine in Austrian omnivores, vegetarians and vegans. (Link)

Chronic psychosis associated with vitamin B12 deficiency. (Link)

Comparison of four types of diet using clinical, laboratory and psychological studies. (Link)

Cyanocobalamin (vitamin B-12) status in Seventh-day Adventist ministers in Australia. (Link)

DHA status of vegetarians. (Link)

Dietary intake and biochemical, hematologic, and immune status of vegans compared with nonvegetarians. (Link)

Dietary intake of fish, omega-3, omega-6 polyunsaturated fatty acids and vitamin D and the prevalence of psychotic-like symptoms in a cohort of 33,000 women from the general population. (Link)

Dietary intakes and lifestyle factors of a vegan population in Germany: results from the German Vegan Study. (Link)

Fatty acid composition of erythrocyte, platelet, and serum lipids in strict vegans. (Link)

Fatty acid composition of habitual diet. (Link)

Fatty acid composition of habitual omnivore and vegetarian diets. (Link)

High frequency of low serum levels of vitamin 12 among patients attending Jordan University Hospital. (Link)

Homocysteine and cobalamin status in German vegans. (Link)

Homocysteine levels in vegetarians versus omnivores. (Link)

Long-chain n-3 polyunsaturated fatty acids in plasma in British meat-eating, vegetarian, and vegan men. (Link)

Long-chain omega-3 fatty acids for indicated prevention of psychotic disorders: a randomized, placebo-controlled trial. (Link)

Low essential fatty acid and B-vitamin status in a subgroup of patients with schizophrenia and its response to dietary supplementation. (Link)

Metabolic vitamin B12 status on a mostly raw vegan diet with follow-up using tablets, nutritional yeast, or probiotic supplements. (Link)

Micronutrient intakes in a group of UK vegans and the contribution of self selected dietary supplements. (Link)

Negative symptoms presenting as neuropsychiatric manifestation of vitamin B12 deficiency. (Link)

Nutrient intake and haematological status of vegetarians and age-sex matched omnivores. (Link)

Obsessive compulsive disorder as early manifestation of B12 deficiency. (Link)

Omega 3 fatty acids in bipolar disorder: a preliminary double-blind, placebo-controlled trial. (Link)

Organic psychosis without anemia or spinal cord symptoms in patients with vitamin B12 deficiency. (Link)

Plasma fatty acid profile and alternative nutrition. (Link)

Platelet phospholipid fatty acid composition and function in vegans compared with age- and sex-matched omnivore controls. (Link)

Psychiatric presentations of vitamin B 12 deficiency. (Link)

Reduced folic acid, vitamin B12 and docosahexaenoic acid and increased homocysteine and cortisol in never-medicated schizophrenia patients: implications for altered one-carbon metabolism. (Link)

Selective deficits in erythrocyte docosahexaenoic acid composition in adult patients with bipolar disorder and major depressive disorder. (Link)

Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians and vegans: results from a cross-sectional analysis of the EPIC-Oxford cohort study. (Link)

Serum vitamin B12 and blood cell values in vegetarians. (Link)

Supplementation with a combination of omega-3 fatty acids and antioxidants (vitamins E and C) improves the outcome of schizophrenia. (Link)

The effect of diet on plasma homocysteine concentrations in healthy male subjects. (Link)

The energy and nutrient intakes of different types of vegetarian: a case for supplements? (Link)

The impact of vegan diet on B-12 status in healthy omnivores: five-year prospective study. (Link)

The impact of vegetarianism on some haematological parameters. (Link)

Total homocysteine, vitamin B(12), and total antioxidant status in vegetarians. (Link)

Vegetarian diet and mental disorders: results from a representative community survey. (Link)

Very low n-3 long-chain polyunsaturated fatty acid status in Austrian vegetarians and vegans. (Link)

Vitamin B-12 status of long-term adherents of a strict uncooked vegan diet (“living food diet”) is compromised. (Link)

Vitamin B-12 status, particularly holotranscobalamin II and methylmalonic acid concentrations, and hyperhomocysteinemia in vegetarians. (Link)

Vitamin B12 and folate levels in long-term vegans. (Link)

Vitamin B12 levels are low in hospitalized psychiatric patients. (Link)