ETA: The following thoughts and ideas are not applicable if a person if suffering from severe depression or anxiety. Sometimes, simply thinking good or focusing one’s thoughts on the good is not enough. In those cases, where there is a chemical imbalance or other factors that affect emotional health and stability, therapy and medication are absolutely necessary.
The thoughts that go through our head make a huge difference in our life. Jewish law acknowledges this and provides guidelines for what we should and should not dwell on.
It even made it into the Ten Commandments – Don’t covet. What is coveting but letting our mind obsess over someone else’s possessions or their good fortune, to the point where we decide we have to have it?
We are also instructed not to believe gossip if we happen to hear it. We’re supposed to tell ourselves that there’s more to the story. We’re supposed to use our mind to give people the benefit of the doubt, to come up with alternative explanations for actions which may appear less than stellar.
The Torah encourages us to focus on the good, to use our mind to connect to a higher purpose, to let those inevitable negative thoughts that we all experience cycle through, but not linger.
Further reading material: Mind Control, Mind Control