> One of the most important points that rarely come up in these discussions is that schizophrenia is not one illness but a bunch of different ones grouped together that we haven't figured out how to differentiate. You can find several patients that share very few symptoms.

Exactly.

I remember meeting someone at an alumni networking event who worked with mentally ill people, including schizophrenics. He explained to me that a lot of his patients had extreme sleep apnea, and their CPAPs were turned up much higher than a typical sleep apnea patient.

His theory was that some of his patients were mentally ill due to their sleep disorder.

My grandfather started having hallucinations (auditory mostly - i.e. hearing voices and carrying on conversations) and showing signs of paranoia (like thinking his house had been broken into when it clearly had not, thinking people were spying on him). We were afraid it was dementia or Alzheimers.

He went to multiple doctors to verify the cause, but wasn't getting anywhere - didn't seem to really be either thing, but exhibited similar symptoms. He was eventually diagnosed by a super competent neurologist with extreme sleep deprivation due to sleep apnea.

When tested it was determined that his sleep apnea was waking him nearly once a minute, but he wasn't becoming fully conscious and therefore wasn't aware he was constantly waking up. He was never entering deep sleep at all. It was more like moving out of dozing into almost-awake and then back again rapidly all night long. He knew he was tired, but had no memory of really restless sleep.

He started using a CPAP and the symptoms started declining immediately. He was back to himself within a couple of weeks. It was really astonishing - I had never heard of anything like this - and of course it was an enormous relief for everyone in my family.

Yeah that was happening to me. I was being woken up a little less than half that (average of 27 times an hour). I was constantly seeing and hearing things, but they were too indistinct for it to be called something like "hearing voices".

It was more that I really often saw a flicker of motion in the corner of my vision or thought I heard someone mumble or say something that I didn't quite catch. These hallucinations were easy enough to rationalize away - maybe the people near me just took a breath weirdly and I thought it was a word, or a bird flew nearby or something.

I didn't realise any of the above were symptoms until I I noticed they weren't happening to me any more a few years after I had started treatment and hadn't happened in quite some time.

I can easily see myself ending up like your grandfather after a few more years of living with severe sleep deprivation. Ironically I got treatment when seeking help for insomnia (because it took me a ridiculous time to fall asleep and could basically only do it when I was completely exhausted)

And a high intensity cpap was inducing a sleep disorder?

Couldn’t he easily test that by having the patients reduce the intensity?

I interpreted GP's comment differently:

Unusually high CPAP intensity indicates unusually severe sleep apnea, suggesting a connection between sleep disorders and mental disorders.

Reflecting on the impact sleep has on my mental health, that makes intuitive sense.

The opposite: The high intensity CPAP was treating the disorder.

I was rather scared at the time, as my CPAP was almost up to the level of the patients. (I got surgery shortly afterwards.)

But I will admit this: There was one time, prior to my CPAP, where I had trouble knowing if a memory came from a dream or real life. Makes me wonder if some mental disorders are just about having difficulty differentiating between dream state and awake.

I think that’s the case for pretty much all of the major psychological diagnoses. Depression, autism, attention deficit disorder. They’re as much a disease as fever or a rash are diseases.

I think we’re still maybe a step or two beyond the theory of humours in how much we understand the brain and what effects it and how it effects us. We’ll look back at how we’re treating a lot of those symptoms today as barbaric in a few decades, I think.

Most if not all brain illnesses may be due to high oxidative stress/neurotoxicity and brain inflammation. A weak/imbalanced gut microbiome may be incapable of dealing with that, which is why we may be seeing the "connection" between the two (brain illness = weak gut).