If thinking one's own thoughts causes distress, why bother? Very little thinking is required to plan the day, and that can be directed by God. Recreational thinking beyond that is unnecessary. But what to do instead? Pray. Recite or listen to liturgy. Read. Listen to audiobooks of great thinkers. One could do worse than to listen on Audible to every word that C. S. Lewis has ever written on any subject. Most of his essays and books will required multiple listens and some will require some research to make full sense of. That will keep a person busy for maybe six months. There are many other people one could choose. Plato. Tolstoy. Take your pick. Writers if not overtly spiritual then at least with a spiritual bent. Why think when you can read? When you can fill your mind with others' thoughts? Why should one's own be of any value? How did one pick oneself as the person whose brains one is trying to pick? Spurn the hubristic assumption of contemporary individualist mores that everyone's view is important and instead steep oneself in thinkers whose thought is tried and tested. It is difficult to remain depressed when extracted lengthily from the swamp of one's own morbid reflection. If thought is too much: the liturgy of the Divine Office or the siddur will also suffice. Anything is better than the random electrical misfirings and chemical spurts of one's own physical brain.