Does PDID fall under secondary dissociation? Can there be a form that falls under tertiary dissociation, or is that position specifically reserved for DID?
Long post ahead (tw suicide attempts)
I was diagnosed with OSDD 1a about a year ago due to prominent amnesia. Daily amnesia that I had never experienced before, back when the previous host was living for ten long years. We lived in specific, claustrophobic conditions that completely excluded any contact with people. My host was somehow aware in advance that this structure was necessary for us, or, as he thought, for his survival. There were other alters who took over when the system needed to rest, so we had a child who really loved toys, and we would turn into an eight year old boy whenever we allowed ourselves the right to relax. Both alters are completely unaware of childhood before the age of eleven, or if the child is aware, he sees no need to talk about it. Both are cold, calm, apparently normal parts of the personality. They seemed to have a good relationship in a way that coconsciousness existed, so daily amnesia was fairly minimal, if present at all. We lived like that for a very long time, until those claustrophobic conditions collapsed, and we were forced into contact with people. The previous host has AvPD or SzPD with terrifying OCPD that almost cost us our life. We fell madly in love with someone, which includes me and the host, as well as most of the system that identifies under our name and history, meaning not introjects, fictives, caretakers, protectors, and so on. Then I came into existence out of the need to express these suppressed emotions. My host primarily held control, and I was like a force of nature outside his control. For a long time, I was an EP, until the previous host could no longer cope with the pressure of a chaotic life and his inflexible problem solving methods in everyday life. I took on more and more power, and when I fronted, it was usually to express sexual needs, a fixation on my own appearance, and a need for emotional connection, which was the exact opposite of what we had from the previous host. I have no memories from the past before the age of eleven, but I share memories with the previous host for certain things, although I am sure there are things he knows that I do not know, for example, his overvalued strategies on how to do things at his job, as that entire part is blurry to me. As I was taking over leadership, he would just give up for a while and disappear. We had no communication, and I continued with my propaganda, almost unaware of what he had been doing and how I ended up in certain places at times. We did not talk because I did not know I could address him. I thought I was all of it, just a little crazy. When we diverged so much in our needs, goals, and values, the previous host went into dormancy, not knowing how to handle himself and life, while I went through various sexual traumas that later created new EPs. All of this happened without any direct connection of ours to the past, stemming from phobias of everyday life and a low adaptive ability to navigate society and personal emotions for the first time in our life.
After he went to sleep, I was unaware of my plurality, even when I was severely triggered and when they all had the chance to show themselves. And then, when I stabilized and learned how to run the system, certain prominent sexual needs simply vanished from me, and I thought I had overcome that phase, when in fact I had split and become the main ANP. This could still fit within secondary structural dissociation because the first ANP weakened and disappeared, so someone had to take control, but the problem is that he soon returned, leaving the two of us as two ANPs. Back then, when he was taking control, we had extreme somatoform reactions, paralysis, seizures, and unexplained bodily pain. We were terribly ill. We thought we were going to die, and the previous host actually wanted to kill us all because we had broken all of his imagined rules and his idea of self. I had psychotic symptoms where I hallucinated that something had happened during amnesia, meaning complete blackouts, attacks of strange, extreme emotions that I would then forget how or where they came from, as well as auditory and VISUAL hallucinations. My system was unable to cope with someone who possessed so much power, someone who had been the host for years, while I had only been there for a couple of months at that point. He had the power to push me off the front, but out of fear for my own life, I fought him. We switched constantly, and our brain was unable to allocate consciousness and power to just one of us, so we were paralyzed the entire time.
If something like this happened to me today, I would surely split. I split over less drastic things the last time. But all of this can still be classified as secondary dissociation under extreme conditions.
After that, I managed to calm down for a while, for both of us to calm down, because he wanted at least to know what was actually happening to him before committing suicide. We found out about dissociation from a foolish paramedic when we had a seizure that looked like epilepsy, so people literally carried us to the hospital. That was when they saw on the scans that we were not having epileptic seizures. After that, I was sent for an urgent psychiatric evaluation and given strong sedatives, specifically benzodiazepines. I had wonderful friends by my side at that moment, and the guy my previous host was running away from, you could say the guy I am figuratively engaged to, despite him being one of the triggers for my madness, because our love is obsessive and all encompassing, and because even I, let alone my previous host, am afraid of it, took care of me with such care and tenderness that I was hypnotized. Then we entered a relationship, and love solved everything FOR A SHORT WHILE. I went to therapy and felt an immense need to find out as soon as possible what disorder I had. We urgently wanted to get diagnosed and move on to treatment. I never had imaginary friends, and I believed he and I were similar, more like parts of a single personality than people with different names. Even though we acted completely differently, we still operated under the same name and had a similar concept of what we represented, supposedly. That is why we were diagnosed with OSDD 1. Because of the amnesia that continued to persist and had always been there, though my previous host was completely obsessed with fixing the mistakes we made rather than focusing on the memory gaps he had when I fronted, or those strange moments where you find yourself in a place without knowing how you got there, he had always lived in his head, so he supposedly did not even notice the change. I noticed the change, and the amnesia was killing me. I was pushing harder to figure out how to live with this and discover the triggers and reasons why this was happening, rather than focusing on some step by step theory that he started with, because that idiot is a perfectionist in a way that he would rather spend the next month reading every book related to psychoanalysis and dissociation just to have a perfect broader picture of what is happening to him than actually manage the terrible situation we found ourselves in.
In therapy, we managed somehow, and the symptoms started to calm down completely. We entered mild communication with a part of our system, even though half of it remained locked away, and all those parts were different yet similar. We never had those aliens or mythical creatures that DID patients talk about. Everyone was human and looked like us in one way or another, or at least that is how we imagined them, but neither my previous host nor I had any desire to meet them because we had gone through terribly turbulent periods of life, and these EPs promised new turbulent and severe reactions.
All of this fitted under the idea of OSDD 1a quite nicely. That was until our boyfriend, who meant the world to us, suddenly started abusing us. He has BPD, and whatever he did, he did out of fear. He forbade us from seeing anyone, any friends, out of jealousy. We lived in a house with him and were not allowed to go anywhere, while he left every day to meet his friends. This was not literal physical abuse, though he hit me once when I said I hated his best friend, and he locked me in a room. But this was such psychological terror for me, the idea that he was seeing someone, that my freedom was taken away, that he, who meant everything to me, could not spend time with me because he was afraid he would ruin something, that he found comfort in a guy who was his best friend, that this guy was better than me. All of that brought me to such a state of weakness. The previous host disappeared again, and from then on, I became the main host of the system. I was alone, and the boy was gone too, alone with new EPs, and far too weak to handle them. I dissociated every day, people and emotions took over me, I found myself in strange situations, and my thoughts were so loud that I had to play loud music over them just to be able to breathe. I was literally going crazy again. Then a new alter appeared, completely different from anyone I had known before. My favorite singer from my youth. A different voice, style. Creepy. Jim Morrison manifested in my head. He talked to me, completely different from everyone else. Then another part that I thought was me, but clearly was not, a sexual part, started communicating with him. It was not really communication, but I will not go into that. Jim helped me and took over most of the tasks, but then he started acting out and almost set fire to the house we lived in. He teamed up with other EPs because he thought he needed to break free. He is delusional, believing he is the literal reincarnation of Jim Morrison and has nothing to do with me, that he is just a passerby in my head. I was terrified of him, I thought he was going to destroy everything, that he would take revenge on our boyfriend. Then a new alter manifested, an introject of my best friend, who came to protect me emotionally. Jim stopped attacking us once we somehow explained the situation to him, but I ended up with two completely different new ANPs, ANPs who also have no idea what happened to us in childhood. So, what on earth is this? This certainly is not OSDD 1. I think I have covert DID.
Firstly, it's important to note that the levels of structural dissociation and the different DSM or ICD diagnoses a person can receive don't map onto each other exactly, as they don't measure the same things.
Generally speaking, P-DID and OSDD fall under the higher end of secondary structural dissociation, and DID falls under tertiary structural dissociation. But given that it may be possible for someone to have multiple ANPs and still not meet the criteria for DID, or for someone to meet the criteria but only have one ANP, that can be taken with a grain of salt.
This is reflected in The Haunted Self, such as here:
"In our consistent clinical experience, most patients with DDNOS have developed secondary structural dissociation."
"We propose that secondary and tertiary dissociation differ along several lines. In secondary dissociation (and DDNOS) there are less profound amnesic boundaries among parts of the personality. ANP is by far the most extensive part of the personality, the “major shareholder.” EPs tend to emerge in daily life less often, and tend not to be mediated by the action systems of daily life. Thus EPs in secondary structural dissociation are more likely to be mediated by defense only, and there is more tendency to have only a single ANP."
Note that "DDNOS" is the old name for OSDD.
Especially in the modern day, most professionals acknowledge that there can be some variation as to where different diagnoses may fit under this model. OSDD and P-DID are often thought of as existing on the "bridge" between secondary and tertiary structural dissociation.
This means that some people on the higher end of secondary structural dissociation may technically meet the criteria for DID, and some people on the lower end of tertiary structural dissociation may technically meet the criteria for OSDD or P-DID.
You can't exactly speak in absolutes with this kind of thing because there's so much variation in people's internal experiences, and language is always going to be somewhat limiting.
Also worth noting that mixed parts exist, and often develop as a result of either an EP taking on responsibilities of daily life, or an ANP experiencing trauma without splitting. This is most commonly experienced in DID, but I don't believe it's impossible for it to occur in OSDD as well.
I can't tell you what you do or don't have, it would be best to see a professional for that. Sometimes people do confuse covert DID for OSDD, though. Sometimes professionals misdiagnose DID as OSDD due to amnesia and dissociation preventing the client from reporting all of their symptoms as well.
At the end of the day, the exact diagnosis doesn't matter that much since they're all basically variations of the same thing, and are treated the same way. It's obviously useful to understand how your system functions, but you don't necessarily need to stress about which label fits best to do that.
Hope you're able to achieve some stability and peace with your experiences, it can be quite an exhausting process to go through.