You think you know why your friend is quiet lately. That’s a guess. Test it with a question.

An explanation your mind supplies for someone else’s mood is a story built from your own material, usually featuring you. It may be right, and it feels equally certain either way. A quiet friend might be tired, unwell, absorbed in something private, or carrying something that has nothing to do with you at all.

Ask rather than deduce, and ask in a way that leaves them room. Something plain, like saying you noticed they have been quiet and wondering how they are doing. If they would rather not say, the asking still lands.