Since no one can define mental health, because these soft qualities only ever emerge in the context of the one in whose immediate environment people exist and interact, it is impossible to provide a fixed definition.
Therefore, in the same way, it is impossible to define mental illness.
Everything is an ongoing process, always responding to change and giving its own impulses. Why we nevertheless believe that there are definitions to be fixed in space-time probably has to do with the fact that we live in a society based on the division of labour and therefore meet with mostly strangers who spend limited time with us and therefore look for classifications in order to be able to assess us.
Pigeonholes and labels seem to give people more of this security the less you know each other and have to deal with each other on a daily basis, but are a delusion in my eyes.
How "disturbed" someone is considered depends on how those around the "disturbed" person perceive this disturbance. If one understands normality in the sense that no conflicts should occur, that one acts in an avoidant rather than a confrontational way (as can be observed as a habit in family systems, for example), someone who approaches the conflict in a confrontational or direct way would already be a "disturber". But where the tendency is more towards confrontation, the avoider of conflict would rather be the " disturber".
What is disturbing is always that which goes against the tendency that a group of people habitually exercises. But since groups act separately from each other (the team at work differs from the family or the sports club from what one does at university, etc.), the behaviour of the individual also differs. Since people are able to take on many different roles and perspectives, even without always being aware of it. Schizophrenia is something normal not unnormal, seeing in this sense.
However, there is really no need to worry, as no two people are ever alike. We all have different degrees of concentration and there is no need to divide people into productive or unproductive. Because the unproductive produce something, for example they slow down certain developments, put obstacles in the way (consciously or unconsciously) that impede the overly productive from wanting to advance something too quickly. Such events occur on both a small and a large scale. Ignorance is therefore also a good concept to provide an alternative to the actionists as well as to those who resist actionism.
Fortunately, there is no "one quality" that makes a person successful or unsuccessful, it is a whole conglomerate of qualities that interact with the many qualities of others and influence each other, a basically unanalysable dynamic that, because it defies analysis, is something unpredictable.
I find it is nothing bad to not being able to see into the future. The fun or irritating factor is though, when I believe in the concept of predictability, I might influence the future by this very conviction of mine and fulfill the famous prophecy. LOL