I was never addicted, but it certainly was something I spent a lot of time and money on for many years. In the early days I spent most of my free time visiting thrift stores, flea markets, and Craigslist to find deals on games I wanted, and it was something I really, really enjoyed. From about 2010 until 2013 were amazing years, and even after that the hobby still had its high points, and I still continued to look for cheap games in the wild and online, albeit less often gradually since I stoped finding good deals as often. Despite all this I never spent so much money on games that I wasn't able to pay my bills and I certainly never ruined any relationships I had as a result of my interest in collecting. As of now I guess I'm still technically a collector, but I do not actively collect anymore, but rather just pick games up that I want to play right after buying them, and on rare occasions find a game that has sentimental value and will buy it if the price is right.
I've certainly seen what game collecting addiction looks like in this hobby however. There are two collectors specifically that come to mind when I think of addiction in this hobby. The first guy was actually a friend of mine for a while and his intense, obsessive personality made him ripe for becoming addicted to video games. He used to hunt for games at all waking hours that he wasn't at work, and even then he would look for games on the way to service calls or on his breaks. I belonged to a facebook group that he belonged to as well and nearly everyday he'd post pickups on the level of what the flea posts here every other week or so in the pickups thread. His collection was massive as well as a result of this. I later found out the darker side of his collecting addiction. At one point he was spending $5000 to $12,000 a month on video games, and even with flipping doubles he got severely into debt because of his collecting habit. He was actually forced to sell big chunks of his collections to get out of this debt several times, but of course all he did was buy more and more games after that debt was resolved. The other guy I know who was definitely a collecting addict was pretty similar, but his story is a lot more sad. He is a trust fund kid, but also works full time which is respectable. But what's sad is his collecting is more a symptom of hoarding I think than of being genuinely interested in collecting. He had several local collectors over a while back and his house looks like a giant storage unit with video games, toys, odd collectibles, and all kinds of other stuff literally literally litered in every room in his house. Essentially his house looks like an episode of hoarders, but with fun stuff everywhere. He also has like 6 cars, half of them don't run. He has some serious, serious problems and you can tell that video game collecting is not just an addiction, but a compulsion for him that he doesn't recognize.