Premanand Maharaj Ji
Why do I get depressed and overthink so much?
Impure mind leads to overthinking
Sinful conduct makes the mind impure, and an impure mind breeds negative thoughts and useless worry that leads toward depression. To stop it, sing God's pastimes, listen to them and do naam jap.
Our mind has become impure because of sinful conduct. Because of that impurity come negative thinking and useless worry, which is called overthinking.