my otherwise wonderful dog, adopted from a rescue org when she was ~3 years old, plainly has PTSD from prior trauma. she spent the first 3 months with me going through frequent cycles of fear diarrhea, usually in the very early morning hours.
i can only guess that she was treated badly by a very overbearing/masculine person in tight quarters, based on her uncontrollable fear reactions, which almost always happen at home. outside, she's generally friendly toward women, mildly curious/cautious of kids, and fearful/cautious of men. we've largely worked through the diarrhea, though sometimes it triggers if she thinks i'm mad at her for any period of time, even if i get angry for reasons totally unrelated to her.
she still sometimes exhibits extended bouts of panting, scratching, and self-nibbling as she tries to regulate the autonomous fear reaction. distraction, petting, hugging, and other countermeasures sometimes but often don't work in calming her down. it still breaks my heart every time, even 2 years on.