Speaking from personal experience. I have a sibling with psychosis, on meds, hospitalized every so often. Also, one of my parents has been treated for ptsd and depression for more than 20 years.
The shrinks are clueless to put it mildly. What they do is try out different dosages and combinations of meds to see what helps until it doesn't and then they give up. Their practice is akin to witchcraft and mixing potions in the medieval times.
My honest opinion is that psychiatry is at best a pseudo-science and needs to be abolished as a field of medicine.