I found out after overcoming most of my problems that I was born with a mast cell disorder. What happens is certain triggers such as stress, pollen, high histamine foods, and milk affect the mast cells which cause mild brain inflammation which results in cognitive dysfunction and "brain fog." That would have altered how I perceived the world and the cognitive distortions I formed caused me to become depressed, anxious, and misunderstand people as well as created more stress that further impaired my brain function.
Once my stress that continually affected my mast cells went away, my autistic traits started to vary which makes it easy to tell which symptoms are caused by the mast cells. Because of that, I know the mast cells cause my nonverbal impairments, slow processing speed, sensitivity to sound, and preference for sameness and routine (to cope with the "brain fog").
My severest symptoms of autism (failure to initiate or respond to social interactions, a total lack of facial expressions and nonverbal communication, absence of interest in peers) were caused by depression. Later, when I was less depressed, cognitive distortions caused much of my anxiety, social awkwardness, and trouble understanding people (although the "brain fog" certainly contributes to it).
My point is that a mast cell disorder + cognitive distortions (which caused depression, anxiety, stress, and trouble understanding people) resulted in me meeting the criteria for autism and correcting my thinking caused me to no longer meet the criteria. Regardless of whether you think I had autism, I met the criteria, which means other people who currently meet the criteria may be able to recover like I did.
As far as personality, when I became less depressed, I started to be interested in people and wanted friends but I wasn't able to comprehend social interaction. I also had and still have sensory overload when something triggers my mast cells.
Another thing is research is indicating that maybe 1 in 10 people suffer from mast cell activation syndrome and a study found that 1 in 10 people with a mast cell disorder are autistic. That means 1 in 100, or 50% of people with autism, may have become autistic for the same reason I did.