I'm not him, but most mental illnesses are exacerbated by excessive stress. For example depression, anxiety, and OCD. What causes stress varies person to person

I'm not him, but most mental illnesses are exacerbated by excessive stress. For example depression, anxiety, and OCD. What causes stress varies person to person. For example, consider you have inflammatory bowel disease (IBD). Some food causes you pain, discomfort, and stress. Over time, eating the wrong diet can worsen your anxiety. You might fear going out and having fun, because you have to use the bathroom too much. Then, in that sense, a diet incompatible with your genotype triggers your anxiety disorder. Or consider a stressful job, like being in the military. That might trigger or cause PTSD. Then, later down the line, another stressful job might trigger that PTSD.