Not surprised at all - diet

From The London Daily Mail:

Eating meat may IMPROVE mental health and one in three vegetarians are depressed, study suggests
A vegetarian or vegan diet may be increasing the likelihood of depression, a US-based study suggests.

People with a plant-based diet were twice as likely to take prescription drugs for mental illness and nearly three times as likely to contemplate suicide.

The report, which looked at more than 160,000 people, also found that a shocking one in three vegetarians suffer from depression or anxiety.

160,000 is a good sample size - they are not going to have to argue their findings.

There are some health benefits to a veggie diet - I am about 80% veggie and 20% carnivore. Still, studies like this really point out the strong links between diet and mental health.