Reminiscences are afterthoughts of memories. In most cases they are of traumatic origin.

Reminiscences are deep memories that leave a mark, either good or bad.

Memories come and go at any time.

Reminiscences are mostly common from mid-life and stored permanently.
That explains why the elderly better recall the past vs the present.

Another way to look at it, is seeing reminiscences as an afterthought of memories.

It’s virtually unlikely having reminiscences in our teens, those would account for trauma.

Trauma must be treated accordingly thus belonging to an independent category of mental illness, most likely PTSD.

Reminiscing is not a mental disorder.
We all do past 40/50.

I reminisce the late musician David Bowie who passed in 2016 at 69.
I grew up with his music in the 80s.
He s deemed the most influential glam-rock artist of the 70/80s.
His legacy will never end.
There are hundreds fan-groups dedicated to him on all social networks.

Up until his death, I had beautiful memories of his.
After his death, those memories turned into sad reminiscences.

I question myself if it is correct to make departed celebrities live eternally on this earth…
David Bowie withdrew from the public sphere long before his death in 2004 at 57.
He stated of wanting to spend his last years with his family.
He had not stopped touring since the 70s.
He gave enough, he desired some time alone.

In his last track ‘Lazarus’, he sings 

 ♪Look up here, I m in Heaven, everybody knows me now!

Could it mean: “Remember me in Heaven!”…….

R.I.P Starman