It's a tempting for me to limit a movie to what my mind fixates on as its "central theme." This is especially true of horror. Carrie is about menstruation, Cat People = repression, Antichrist = depression, etc. I think groupthink/junket critic culture only contributes to this narrow perspective. I'm guilty. The first time I saw Possession, probably seven years ago, my mind kept repeating, "love is nuts." While I think that about sums it up, there is so much more to Zulawski's vision.
Filtering it through my limited (insert pronoun here) perspective, I was reminded of two instances where my significant other had simply gotten over me. It's maddening, especially when you have such a conceited view of companionship. As I tried to reason and talk my way back, I found the other person as steadfast as a brick wall (pun intended as this was filmed in West Berlin.... Junket wisdom). The inability to bend another person's will is the ultimate spat in the face of privilege and, in the case of myself, the best way to chisel through. Pride is the most potent ingredient for madness.
Possession was being filmed as the director was ending his marriage to actress Malgorzata Braunek. I know none of the details other than that junket wisdom implies that it was "messy." They had a ten yr old son at the time, which can only add more pain and guilt to the equation.
Possession follows a married couple in the throes of divorce, sparing us none of the messy drama therein, including the slimy/bloody/tentacled materialization of Anna's anguish or empowerment, or both, or much more. Shit hits the fan, but it's all still somehow grounded in real emotions, ones that I happened to be feeling at the time. The creature calls Pickford's Model to mind, specifically how monsters can be summoned and given life through delving deep into one's mind and emotions. John Carpenter's underrated In the Mouth of Madness did too. I like directors like Zulawski, who don't hide their dirty side. I think the same could be said for Denis, Ferrara, Cassavettes, Scorsese, Peckinpah, and Lynch.
If all of this is muddled and chaotic, it's true to the movie itself, which you should all see.