As a man who suffers from psychosis, at this point, my illness is under control to the extent that I can go months without having very many "delusional" thoughts.
Delusions can be defined as erroneous thoughts generated by the psychosis of the mind. In some rare instances, a delusion can turn out to be correct, even though its origin was the symptoms of a psychotic illness. However, inaccuracy is usually one part of the definition of a delusion. Secondly, the beliefs tend to be weird, unusual, extraordinary and often paranoid.
It is usually not apparent to other people when some amount of delusional thought has taken hold. If no action is taken to deal with the first few delusional thoughts, the delusions can sometimes grow into a "delusional system." This is a somewhat organized group of delusions that form an erroneous belief system. In my case, before I get to that stage I tend to recognize and resolve the delusions before they can multiply.
When at a low level of delusions, these incorrect thoughts are usually not acted upon. Usually, to affect a person's actions, the delusions must be at a medium or higher level.
Using percentages to describe this would be a type of guesswork, since we don't have a way of measuring thoughts. In order to affect actions, we could say that delusions must be at ten percent or higher. When delusions reach twenty percent, a person is in danger of a complete relapse. In a complete relapse, delusions might reach as high as ninety percent.
If a delusional system is allowed to progress, the person can get worse and become fully delusional. By then, the thoughts have lost much of their organization. The false world in which the schizophrenic person lives is almost always inconsistent.
The progression of getting worse for a person with schizophrenia can be stopped in some cases with an increase in medication and in other cases with cognitive exercises to augment the medication.
Since I don't keep any of my thoughts a secret from all people, my "mental hygiene" is assisted by airing out the thinking. While there are some things that I wouldn't tell family, I might tell those things to a counselor and vice-versa. It takes work to get to the point where you have no secrets. This does not mean that everyone needs to hear everything. People should be spared unnecessary revelations.
A typical person with schizophrenia would probably hide a number of their thoughts from others, including many thoughts that are delusional. And this allows the delusional thoughts to multiply. Learning to open up to people takes work-it doesn't happen automatically. Learning to talk about one's delusions requires practice. Before opening up is learned, others may be mystified by someone's behavior and by the fact that they may appear internally preoccupied. The person hasn't revealed the thoughts that have taken hold.
Opening up is not the only practice that helps get rid of delusions. It is possible to set up an internal scan that works for your mind in much the same way that an antivirus program works on a computer. It starts with giving the mind the instruction to identify and negate delusions. There exist several ways that a potential delusional thought can be pinpointed.
I have benefited from learning to evaluate thoughts and to engage large areas of consciousness to do so. When the mind is still mostly living in reality, it is possible to scrutinize the thoughts and weed out the inaccurate ones.
When I became a writer, it helped my thoughts become much more grounded and much more accurate because as a writer I have contact with a group of people (editors mostly) who are grounded in reality. Being isolated is bad for mental hygiene. Being in contact with intelligent people, including via internet, is good.
While there is no "sanity pill" the medications that exist are able to make the brain function more normally; and this gives more of a choice about what will be believed and how the mind will work. It is up to the individual as a whole person to make the correct decisions as to which thoughts to discard and which ones to keep.