We should encourage stronger research designs (including A/B tests) if we care about the impact of AI use on mental health outcomes. A study like this one cannot say anything about the effect at all (it is even possible that AI use will have a positive impact on mental health).
As for this research particular...pfff...I'm rooting for the collapse of this LLM-fuelled craze, so I'm biased.
Anyway there's no reason to discount it, but it does mean you can't run with the assumption that there is causation.
Like even if you accept a bunch of premises to make the studies even work, the raw stats are often so bad and there's no rigor to try and actually explain alternatives that I just have stopped reading them entirely.
Again, I'm not one to hate on the social sciences. History, anthropology, politics, law, psychology, sociology, all of that is very interesting and important. But the horrible statistics that don't understand garbage in garbage out have turned me off of it. Much rather read qualitative studies that actually try to gather detailed, real data, even if it's not as automated as a random survey
I don't think this is a mark against those users to be clear, I see this as largely the same chicken-egg relationship you find between depressed people and video games. It's also subject to the same kinds of abuses on the part of the merchant, things like in-game purchases that are particularly attractive to people with executive function issues, and why the predominant "whales" of the video game industry and especially the mobile game industry are people who are already struggling. I think AI is going to end up in a similar position because like, again, not trying to be shitty, but if your life kind of broadly sucks, I'm sure playing in an AI chatbox all day where something that sounds vaguely human will validate whatever you say, make stuff for you at request, and never challenge you in the slightest is quite attractive to you. And, thinking through it further, these systems also adapt to their users, learn how to engage with them better, as many products have before them that have trapped the neurodivergent into problematic usage scenarios.
I don't judge the people, but I am incredibly suspicious of the businesses behind these and other products that seem almost designed to attract neurodivergent people. If you design a machine that gives dopamine on demand, you can't really be shocked when people who are dopamine‑starved use it a lot. Potentially to a harmful extent.
(I say general-use because I think there are some AI-based tools that are specially made which _can_ actually be helpful for this - but opening a ChatGPT tab, even with lots of relevant instructions, ain't it in my experience. The interface itself is counter-productive to healthy processing.)