I should consult a doctor about my wife’s neurotic hysteria.
See this on the end of a word, and you know that it is a ______symptom. When you have a _____symptom, you have some kind of disease or sickness (otherwise why would you have a symptom of some kind?).
Since this is attached to things, it's treated like a jukugo word, so the on'yomi reading is used here.