A number of years ago I was depressed.
For about 2 months, prior to seeking treatment, I had severe insomnia.
An hour and a half of sleep was a good night. I got to see how incredibly long, and miserable, a night is when you can't sleep.
I found out that Wal-Mart and Denny's are never crowded at 3 AM.
Every time I would try to sleep, and would close my eyes, I would visualize different images from my past.
The images followed no particular pattern, but would be of folks I had interacted with in the past including family, friends, classmates, co-workers, enemies, etc..
I couldn't shut my mind down.
At the time it reminded me of watching a slide show.
When patients are depressed, report insomnia and the inability to stop thinking at night, I always ask them if they are experiencing a "slide show of their life."
A lot acknowledge it's exactly like that.
"How did you know?" they ask.
"Been there, done that," I reply. "I had the same problem a number of years ago when I was depressed. Let's talk about what we can do to help you get some sleep."