The vast majority of depressed people do not demonstrate symptoms of gaming addiction. Even if one were to accept the argument that gaming addiction is always caused by underlying depression, that doesn't mean it shouldn't be considered separately from garden variety depression - there is often a nasty positive feedback loop between depressive symptoms and addictive symptoms. Besides, psychiatry in general needs to be increasing the precision of its definitions if we are going to get anywhere with new treatments.

Ironically, depression is often caused by other underlying disorders (e.g. Autism), yet if the symptoms are met there will be a comorbid diagnosis, rather than saying that depression is just a symptom. It can be difficult to disentangle cause and effect for a lot of comorbid diagnoses, and also many existing treatments address symptoms rather than causes. So the distinction you are making hardly exists in the field at large (at this time).

As for the deeper question, "could an otherwise healthy person develop gaming addiction?", I'm inclined to answer yes. It of course depends on how you define "otherwise healthy", as I'm sure we could identify genetic risk factors for gaming addiction, and I bet they will correlate with risk factors for addiction, ADHD, etc. However I've certainly seen people who were functioning well but perhaps a bit bored at school/work or a bit anxious in social situations take a complete nose dive when they got hooked on the "right" game.

I'm curious if you would say the same thing about gambling addiction?

Edit: just to add I am 100% against anything like what China is doing. I think we need more resources to help those who are spending more time gaming than they would like, which involves recognizing it as a legitimate issue. I also wouldn't mind some restrictions on the tactics game companies can take to make their games addictive, although the details of that would require careful consideration.

The vast majority of depressed people do not exhibit exactly the same symptoms.

No shit, that doesn't change anything I said. The definition of depression is hilariously vague, the last thing we should do is lump additional (relatively) well defined issues under "just depression". Besides, there are certain symptoms that do appear in a high percentage of patients, gaming addiction is most definitely not one of them. The point is not about aligning symptom profiles exactly between individuals, it's about looking at classes of symptoms across a broader population. Nobody in their right mind would say addiction is "just a symptom of depression", even though it can be correlated with depression to a similar extent as gaming addiction can be.

Undervalued comment that doesn't vibe with mainstreams interpretation of "gaming addiction." I only became "addicted" after both my parents almost died of medical conditions. It's easier to write it off as "gaming addiction" in the same way certain drugs are "gateway drugs."