Projection Theory (also explaining all the wolves)
I like to think about psychological causes of therianthropy, since I do not believe it to be something one is born with/something spiritual. After some time of thinking, I have come up with a possible explanation, which at least works for my case.
My idea is, that identifying as something other than human is a projection of the human mind (If you're familiar with it, Feuerbach used a similar approach trying to explain religion on a psychological level).
I mean that there was at least one experience of a person, that made them feel weak. Maybe other kids were mean to them or they were always alone, problems at home, physical/emotional abuse...there's a ton of things that can happen in someone's life that makes one feel powerless, weak and afraid.
From this feeling, the brain usually develops a coping mechanism. It might shut-off, develop DID, give the person anxiety etc.
I believe that therianthropy develops as a coping mechanism. For things many of us might not even remember.
Getting to the part, that many wonder about: Why so many wolves? Why dragons and overall strong creatures, which are mostly feared among humans?
I think it's because those animals we see irl or portrayed as strong in media, make us feel powerful. They give us something to latch onto while/after facing harsh situations. It is an inner projection of our self onto a stronger being. A wolf for example can run fast, has strong muscles and could easily defend itself by biting and scratching. It often has a loyal pack that will always be there for it. It is feared by humans.
If people who did you wrong would see that strong animal side of you, they'd be scared and have respect of you and never dare to hurt you again. When we feel weak -or different- because of others, we want to escape that feeling. We need something to help us feel strong again. Many people have their family or friends to tell when they need help, and if all goes well they get the help they need to feel okay again.
Not everyone has that. Not everyone can ask for help. Not everyone gets it when they need it.
If that is the case, your brain will find another way to cope. Be it aggressions, antisocial behavior or feeling that you are an animal born into the wrong body, the wrong life.
To sum it up:
I believe therianthropy develops out of trauma (or just feeling weak) and leads to the feeling that you do not belong into this life and are something different from those other people that did you wrong, usually something stronger.
As a reminder: It is just a theory of mine, not a fact. It is what I find most rational and believable among the theories I have read so far. It is also not an attack or criticism of therianthropy in any way. I am a therian myself and don't think of it as something bad in any way. I think it's amazing to be able to see the word from this angle and be far more open-minded than 'normies'. I hope this gets some people to think and theorize for themselves.
Have a great day, stay yourself. Awoo