"online addiction" is correct and can be used in written English.
For example, you could use the phrase in a sentence like this: "The increasing prevalence of online addiction has created a need for more research into its effects."
Is online addiction a growing problem?
China will ban the opening of new internet cafes from this July in a government campaign to clamp down on online addiction and juvenile crime.
There's a weird serendipity to the launch in the same month of Grand Theft Auto 5 and the cinema release of In Real Life, Beeban Kidron's documentary about teenage online addiction (now that's a tough choice for a Friday night).
Psychiatrists are swamped with patients coming in for cures for online addiction.
Psychiatrists are swamped with patients coming in for cures to online addiction.
Our results confirm the need to establish health prevention programs such as Internet-based prevention for MMORPG abuse and a Centre for Online Addiction, as initiated by Young, including online consultations (http://www.netaddiction.com) and treatment such as cognitive behavioral therapy [ 48].
Many online addictions, Young said, stem from a desperate need to control an outcome – any outcome.
And it's not just us parents who are made miserable by our offspring's online addictions.
The most successful type of treatment for online addictions appears to be traditional cognitive behavioral therapy, although there are relatively few published studies examining its efficacy in relation to social media addiction.
To combat what authorities deem the greatest social crisis for youth today, the Chinese government has created treatment facilities to detox and cure teenagers of their online addictions.
Feelings of loneliness and anxiety often accompany gaming and online addictions.
