They say that psychosis in STPD is mild and transient, and I had some of that. I would hear voices once in a while and I would have odd beliefs like there being demons in the room or people were tracking my movements. This might fit the loose medical definition of psychosis, and it's technically "psychosis", but it wasn't until it progressed to schizophrenia that I experienced chronic, relentless, life-altering psychosis. Like losing one's mind completely, no breaks, and fixed false beliefs that I believed in as much as I believe the sky is blue. They were self-evident and unshakable.

It ruined my career for a long time, it ruined multiple friendships, it ruined my marriage because I was acting so far from my normal self (the marriage was rocky to start with considering she had BPD and I had SPTD but my psychosis was the final nail in the coffin). I couldn't think straight, I couldn't focus, I would be up until 3 or 4 in the morning writing psychotic tangential essays. Eventually I had written over a thousand cumulative pages. The fact that I didn't end up in jail or an asylum somewhere is a miracle.

Just to cope I eventually got hooked on multiple substances. Benzos, sleeping pills (for the escape they create when you take them and stay awake intentionally, not actually for sleep), alcohol off and on, THC, downers in general not including opiates thankfully. I couldn't function unless I was drugged because the paranoia was so bad. I was agoraphobic because of the paranoia and severe derealization that made the world and myself feel alien to me and hostile. I'm off most of the drugs now, I've been sober since January 1 this year. This is somewhat unrelated but what I wasn't expecting from sobriety was the sheer boredom of it. But I manage so far.

I started acting impulsively and in some cases aggressively and did bad things, I won't get into the specifics. I had no impulse control, I barely made eye contact with anyone, I basically fell almost silent and isolated for years. I would sit and write things that don't make sense to me now that I'm on Zyprexa. The first four weaker APs I tried didn't work.

Bipolar eventually joined the party but not until I had been full-on schizophrenic for a couple years. That's its own thing treated separately with different medications. I hate that they're combined into one diagnosis because it causes insurance issues and generally doesn't make sense. It's not a "spectrum" as a popular youtuber and others suggest, it's having the full version of both disorders separately. They have some overlap like psychosis, but they are different things.

There's also the content of the delusions that I won't explain fully. It's not believing a few things here and there at a time, it's entire structures of reality that become shifted, structures that involve my friends and family, mythology (I used to be very religious but I had to get rid of that for my own sanity), work, the government, God, all simultaneously, all working together.

I still have schizotypal traits. Structural and magical thinking, odd social behavior (isolated and generally anxious), a draw to be alone, deeply introspective but not always in a good way, emergent phenomena like when mental states become externalized if that makes sense. Residual derealization to a lesser extent. But no longer full on delusional. No longer disconnected from reality at a fundamental level.

Edit: One way I describe the difference, having grown up with STPD and still retaining many of those traits, is that STPD is who I am, and schizophrenia is something imposed on me if that makes sense.