When does the disposition of one who is legally sound become invalid?

Answer:
The limits at which the disposition of an owner becomes invalid are:
1. Madness: if the owner becomes insane, his disposition over his property becomes invalid.
2. A life-threatening illness: if the illness of the sick person reaches the point that death is imminent, his disposition is invalid except in one-third (of his estate).
3. If the owner suffers a wound from which death is certain, his disposition over all his wealth becomes invalid, and he is considered, in legal ruling, as being dead.
4. If the judge rules that the owner is interdicted from disposing (in his property) because of his squandering in his wealth, or because debts encompass his wealth, or for a similar reason.
5. And there are scattered issues, such as disposition regarding charity before it is taken possession of, and regarding khums before it is authorized, and regarding pledged property, and so forth. This is an answer to one of the two possible understandings of the question.
As for the second possible meaning of the question, it is that a person who is normally sound in his transactions may be overtaken by such intensity and anger that his disposition is no longer sound. What is the limit of anger which, if reached, invalidates his disposition?
The answer: The limit in such a case is that a person in his anger and intensity reaches a point where modesty (shyness) departs from him, and this is known by his raising his voice and speaking with what is not befitting.
This is the meaning of what they have mentioned, and it is in al-Taj (the commentary); its exact place has slipped from me. What they have mentioned is strong; for sound intellect restrains a rational person from doing what he would be ashamed of before people. So when a rational person, among people, does because of anger what one would be ashamed of, then his intellect has diminished and weakened.

Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2