Hi @Lilymills14 ,
Having a loved one in psychosis is very scary and being the person in it is harrowing.
Psychosis effects everyone differently and isn't particular to Bipolar & Schizophrenia, just about all diagnoses can escalate that far where hallucinations and delusions manifest while unwell. But it sounds like your partner may have lashed out at you, or behaved in ways that have really rattled you.
It is by all means possible to develop traumatic stress from being a carer or from being in a mental health unit with other acute patients.
To spring back only after a few months, I am not a doctor, but I am thinking that it could have been drug induced, but then again possibly not. But your partner has been very lucky that it didn't derail him for 12-36months like it does a lot of people.
Has the psychiatrist told you if they believe it was?
It can't be easy having another variable to contend with, with the addiction. He would have to completely detox for quite a period for doctors to get an accurate diagnosis and to see his mood across time, drug and alcohol free. Maybe that he is able to tolerate high amounts of drugs or alcohol is an indication that he doesn't have a severe case, because it would flip his biology if he did & he'd end up in ED again, but that is no reason to feel comfort, mental ill health can come on so suddenly for all of us, and most people are at risk to some degree across the life span.
My psychiatrist said that psychiatry really lost something when they started becoming obsessed with 'symptoms' like checking off a list, and going straight to a diagnosis, and turning away from the phenomena, and ceasing to examine the actual content of hallucinations. By examining the nature and content of hallucinations an experienced doctor will be able to tell if they could be dissociative or trauma based hallucinations as opposed to drug induced or something like BP or SZ. At the end of the day only the couple knows the sticking points in their relationship and if the cheating paranoia could be relieved with some relationship counselling it may be worth looking into it.
The body will also give the doctor some clues, especially the heart rate and blood pressure and if bradycardia is persistent they will get some clues and a little more info about the person's experiences by looking at the physiology and not just the mental health without having to ask the patient explicitly. Marks can be left on the body and nervous system and this may help the doctors come to a more accurate diagnosis.
I think irregardless of what your partners diagnosis is, the relationship would need help from a trained professional to help you navigate past this traumatic time. Its not possible to do it on your own and we are not supposed to.
If I was in your position I would get myself individual psychotherapy too because you need a private space where you can talk without fear of aggression and blame. I hope you can find the right professionals to help you on your journey. You guys might break up for very pedestrian common place reasons that effect all couples and not to do with mental illness. You still have to be compatible to make it work and currently your needs aren't even being heard.
Corny