"Our analysis revealed that individuals suffering from mental disorders consistently showed lower frequencies of meat consumption during the past 12 months. These results again indicate that a current vegetarian or low meat consumption diet pattern is associated with elevated prevalence rates of mental disorders."
"On the whole, our analysis of food items indicates that avoidance of meat consumption is (positively) associated with mental disorders. Since established biological mechanisms do not explain this pronounced association, one could speculate that the phenomenon may be attributable to psychological mechanisms. This interpretation is further supported by our results on the temporal sequencing of the start of vegetarian diet and age of onset of mental disorders. For depressive disorders, anxiety disorders, and somatoform disorders and syndromes we found that on average the adoption of the vegetarian diet follows the onset of mental disorders. Although differences in nutrition status before the actual start of the vegetarian diet affecting vulnerability to mental disorders cannot be ruled out completely, our temporal finding is more consistent with the view that psychological mechanisms cause the associations between vegetarian diet and mental disorders."
"Health, ethical, environmental, and spiritual reasons are the most important motives for choosing a vegetarian diet. It is possible that subtypes of vegetarians (e.g., health motivated vegetarians vs. ethically motivated vegetarians) may psychologically differ and show different associations with mental disorders. Correspondingly, future research should be mindful of the fact that vegetarians have various motivations for choosing their diet and should clarify whether certain subtypes may be more obviously associated with mental disorders while other subtypes could even be associated with positive mental health."
- Johannes Michalak, Xiao C Zhang, and Frank Jacobi, International Journal of Behavioral Nutrition and Physical Activity 2012