I would create a conversational AI that can be used as 24/7 therapist. It would talk you out of feeling like crap on the short term and help break whatever unhealthy behavioral pattern you’re trapped into. Help you make new healthy habits etc.. not sure what exact cognitive functions are required, more than one though and I feel like it can be seen as a reinforcement learning problem? You’d need a way to assess one’s mental state, and then define actions (just say things to the subject) that would make you feel better but also challenge you enough to improve your state on the long term