It depends if it is aspected, especially with the Sun or Jupiter. It also depends if the house is intercepted or if Mercury is your chart ruler. But having a debilitated planet affects the house it is in regardless. So having a debilitated Mercury in the 5th house for example may indicate struggling to think for yourself, speaking up for yourself or self-expression, finding the right words to say, or self-education or self-learning. Unless it's aspected by Jupiter or the Sun (and if they are exalted or in their home signs), usually the sign is stronger than the house, unless the house aspects its house ruler or ruler of the houses's sign.