A long time ago I lay awake for hours, terrified that they would be my last ones on earth. I had committed myself to quitting cocaine, which was my second addiction, the first being years of amphetamines. I was devoting myself to cleaning up and getting healthy. But then a friend called who I had routinely done coke with and who always had a supply of the drug. Earlier on that black night, I’d careened backward into the familiar land of white lines on a mirror and a heart racing way too fast. It was pounding so hard, so fast, so loud, I was certain it and I couldn’t survive.

I saw the fact that I did survive as somewhat of a miracle. It would be a nice, clean story if I said I never did drugs again. But addiction is never nice and clean. I did go back to trying to clean up my life, and truthfully I only backslid a couple of times after that — and never as severely as on the night I thought might be my last.

I don’t think back on those days too often, but with Matthew Perry’s death the memories have coiled around me because of how honest he was about his own addiction. I want to tell you something about addiction: no matter who it is or what substance that person is hooked on, loneliness is at its root. For whatever reason — and I have no theory as to why — there are those of us who feel isolated in this world, as if everyone else has some secret formula for getting along, for fitting in, and no one ever let us in on it. That loneliness resides deep inside us, at our core, and no matter how many people try to help us, no matter how many friends reach out, support us, show up for us, it never entirely goes away. It’s vast and shadowy, and also part of who we are. Something happens when we discover a drug, or alcohol — suddenly we have a companion holding our hand, propping us up, making us feel like we fit in, like we can be part of the club. It’s there for us in the empty hours when it seems like no one else is.

“Nobody wanted to be famous more than me,” Mr. Perry said at the Los Angeles Times Festival of Books in April. But, he added, “Fame does not do what you think it’s going to do.” I remember hearing him say that and thinking, right — it doesn’t penetrate that loneliness. I wonder if he ever realized how brave he was to reach past his pain and hone a talent that would make people laugh?