Originally PTSD symptoms, including nightmares, that emerged after a 15 year hiatus. Spent some time focusing on childhood trauma. Then there was work stress, then my spouse became terminally ill and died, then my child hit puberty, then I revisited work stress , then I got involved in a new intimate relationship. Lots of transformation over the past 10 years with the same therapist. Now for me it is mostly relationship oriented, but I don't think that will last forever. But the ongoing "treatment" is self care for me, making sure I'm dealing with the vicarious trauma from my work with traumatized people.

There's a book I just finished, by Lori Gottlieb, Maybe you Should Talk to Someone, written by a therapist writing about her own therapy. Her story is she went into therapy to deal with the sudden breakup with her fiance, but then the complaint evolves into her health struggles and fear of death. It's an interesting read from that perspective; you might like it.