Well, the terms "sane" and "insane" aren't really very helpful. "Insane" could cover almost any unusual kind of experience or behaviour. "Sane" is equally flexible in meaning.
Psychosis is not a disease or condition; it's a symptom supporting the diagnosis of a wide variety of conditions, and is sometimes a direct result of childhood trauma, which can be susceptible to complete remission through therapy.
So you're right - it's not always forever.
Apparently some psychotherapists contend that all of those conditions characterised by psychosis are the result of childhood trauma. [citation needed]
I disagree that the terms aren't "very helpful" as in this case the context should have been sufficient for any adept English reader to comprehend the meaning of my post without digging into the individual etymology of the word choices I made.
Also, psychosis can be the temporary or permanent result of foreign chemicals, injury, or diseases damaging the brain directly such as untreated syphilis.
Psychosis is not a disease or condition; it's a symptom supporting the diagnosis of a wide variety of conditions, and is sometimes a direct result of childhood trauma, which can be susceptible to complete remission through therapy.
So you're right - it's not always forever.
Apparently some psychotherapists contend that all of those conditions characterised by psychosis are the result of childhood trauma. [citation needed]