That dataset, Avon Longitudinal Study of Parents and Children (ALSPAC), has over 9,000 men self-reporting on their eating habits. This study looked at the 350 self-identified vegetarians in their midst. These men completed a survey including a set of measures on depression at roughly the 18th week of their spouses’ pregnancy. Vegans were lumped in with vegetarians because of their small numbers. The researchers found that vegetarian men were more likely, with an odds ratio of 1.71 (that is a 70% increased risk) to be depressed. The authors say they accounted for a range of sociodemographic factors including family history, prior childhood psychiatric contact, educational level, number of children at home, marital and employment status, alcohol and tobacco use and educational level. The longer time an individual had been a vegetarian did not correlate, at least at a statistical significance, with depression.