Can't say whether they're addictive or not. My personal opinion based on my own history is that the reward system in games (levelling up etc.) made me feel like I'd achieved something while in reality, I just entertained myself.
Long hours of gaming and imbibing this translated over into the real world where it became harder for me to put in effort because I had to see rewards accumulate as a score somewhere and that wasn't happening.
Looking back in my childhood, I clearly exhibited sign of addition.
Walking into arcade filled me with joy. Trying to decide which game to play. Imagining if I'm going to finally beat Wonderboy on one coin. Playing Kabal with my brother.
I was a good kid, but I would STEAL money from Mom's purse occasionally to satisfy my arcade craving.
Long hours of gaming and imbibing this translated over into the real world where it became harder for me to put in effort because I had to see rewards accumulate as a score somewhere and that wasn't happening.