From one of the abstracts: “Eleven (44%) of the outcomes indicated that vegetarian and vegan diets were associated with higher rates of depression, while seven (28%) outcomes revealed beneficial effects of the diets on depression. Seven (28%) outcomes found no association between vegetarian and vegan diets and depression, although two of these studies found a higher risk of depression in some groups. . . . The evidence on the effect of vegetarian and vegan diets on depression is contradictory, possibly due to the heterogeneity of the studies analysed.”
When I see a study like this I usually go to Pubmed and see if there are other studies or meta-studies.
In this case there are a couple of recent metastudies:
https://pubmed.ncbi.nlm.nih.gov/34375207/
https://pubmed.ncbi.nlm.nih.gov/32483598/
https://pubmed.ncbi.nlm.nih.gov/36045075/
From one of the abstracts: “Eleven (44%) of the outcomes indicated that vegetarian and vegan diets were associated with higher rates of depression, while seven (28%) outcomes revealed beneficial effects of the diets on depression. Seven (28%) outcomes found no association between vegetarian and vegan diets and depression, although two of these studies found a higher risk of depression in some groups. . . . The evidence on the effect of vegetarian and vegan diets on depression is contradictory, possibly due to the heterogeneity of the studies analysed.”