II am more lucky t/han strong, because most of the time I can hold it together. I have to be in really bad condition before it shows. When I went to hospital my GAF was 25 on admission, and I had been working up to 3 days prior to that. When I was a teenager I had an episode of psychosis that lasted over a month, and I kept going to school and getting decent grades. One teacher pulled me aside and asked if I was OK, but no one else, including my parents, noticed. In grad school I was in a severe mixed episode, but I kept going to class and clinicals, and getting good grades. My advisor was a psych NP, and he recommended that I take some time off, but I didn't listen. I made it to graduation, but then went right off the rails and ended up hospitalized for 3 weeks, then 5 weeks, and then had my license suspended 6 months.
So being high functioning isn't always good because I've had to get very unwell before getting psychiatric care in the past, and that has lead to prolonged and worsening episode. Maybe it would be better if I stopped working/school sooner, but I'm very stubborn.