A feeling of not belonging can effect everyone from any background. A person from Australian indigenous heritage raised in Redfern Sydney can feel this bewilderment when he/she feel detachment from their "mob" in outback Oz. A child from European migrants likely feel different than their parents about the home country. They are Italian but their lives have been Australian. They can feel "in betweens".
Until recently my 61 years has been lacking depth of family information. My family came from Tasmania, a dairy farm and we were forced to move to the mainland for hospital care for my brother. I was a toddler then. On my mothers side the farming life, prior to that we knew that my grandfather started his working life with a bullock team. That's it!! At 15yo I questioned my pop about the family tree. He said "I don't want to talk about it". That caused speculation as to there being aboriginal blood in the family as them days it wasn't mentioned. My cousin did a family tree. It turned out there was likely zero aboriginal blood in the veins and one ancestor arrived in Tassy around 1832.
On the other side of my family only 2 years ago we found out that the migrants arrived here in 1884 from Scotland. This delay was because there was a family rift in 1958 and only two years ago a cousin messaged me on Facebook, a lady I'd never met that happened to be a genealogist.
My point being that there was a massive hole in knowledge of our families past. We felt nobodies. That gulf was not unlike my Italian, Greek school friends in the 1960's or that Redfern resident.
I'd suggest that the mentally unwell is more sensitive to any part of their lives that is not normal, missing facts or lack of depth. For us to be well, well enough to survive ok, we need closure and to get that we need to fill in the voids of our lives and that includes - where we came from and who our ancestors are.
If those voids are not filled then try various hereditary sites on the www. Such information might result in you feeling grand about yourself.
An example. I didn't know that my father and six siblings were so poor they attended church in bare feet in 1930. Worshippers looked down on them in disgust. The children went home never to return to the church again and resulted in my fathers anger at churches for the rest of his life. It filled in a gap for me. Also my great granddad went to Tassy to stop growing. At 13yo he was 6'2". Them days cold weather meant you would stop growing. lol