Yogurt helps me with avoiding UTI's, but I don't think it has changed my behavior. Unless, I had bad behavior with a bad UTI. :0(

I can see where this good bacteria might help in reducing stress/anxiety. It would make sense that eating unhealthy foods would cause crankiness/depression etc..
But, I would think depression would come from having a debilitating disease and/or being almost depleted of dopamine.
But, if a person eats yogurt and it helps alliviate the anxiety and depression, then that is more help to get better. So, why not eat yogurt? It is good for you and tastes good, too.
And, it should aid in digestion. Constipation causes crankiness.