I had a videogame addiction to an online MMORPG called "RuneScape". My cousin showed me it back in 7th grade. I would play it daily and it literally ruined my school life.
I was un-medicated for my ADHD, I recently got diagnosed 3 months ago and lifes going better. (I'm 21 btw)
There's nothing wrong with playing a videogame to pass time. But it's another thing to play videogames and ignore your friends, family, and not do things your supposed to.
How I started to quit -
Admitting that videogames are affecting your life in a negative way
Setting a timer. You played for 4 hours average a day? Limit that to 2 hours by setting a timer on your phone
Are the online friends encouraging you to play? Delete them / delete skype/ discord.
Try to find a physically active hobby that you enjoy (Mine was going for walks and looking at whats around me)
Spend more time with your friends.
Unplug the computer/ xbox/play station.
Finally ask yourself "Do I feel more happy now?"