Unlike the industry funded research you implicitly refer to (tobacco, fossil fuel,...), this study was done by a department of the University of Oxford, which is publicly funded.

The title from actual press release / news item from their website reads this:

> Study suggests little to no increase over time in association between adolescents’ technology engagement and mental health problems, urges more transparent collaborations between academia and industry

The second part wasn't mentioned in the BBC article and pretty much addresses your concern.

From the press release:

> To enable a robust study of life in the digital age, the authors suggested an urgent need for more credible and transparent collaborations between technology companies and independent scientists.

> “We need more transparent and credible collaborations between scientists and technology companies to unlock the answers. The data exists within the tech industry, scientists just need to be able to access it for neutral and independent investigation.”

https://www.oii.ox.ac.uk/news/releases/study-suggests-little...