I think the word ghosts creates a sense of loneliness. Of course it would depend on the context, but the word is not only used in fantastic stories about the souls that linger after death, it also can refer to a specific mood.
When someone has personal issues awaiting to be faced, it is ok to say you have "ghosts". It means you have unsolved issues, that probably are not visible, but are still there.
Also, ghosts creates the feeling of something that lingers in time, waiting alone for something to happen that could set it free, something that has been traped and is waiting for a liberation. It can be taken literally or as an image, in both cases, it gives the reader the sensation of loneliness.