This reminds me of the recurring pattern with every new medium: Socrates worried writing would destroy memory, Gutenberg's critics feared for contemplation, novels were "brain softening," TV was the "idiot box." That said, I'm not sure "they've always been wrong before" proves they're wrong now. Where I'm skeptical of this study: - 54 participants, only 18 in the critical 4th session - 4 months is barely enough time…
I think a better framing would be "abusing (using it too much or for everything) any new tool/medium can lead to negative effects". It is hard to clearly define what is abuse, so further research is required, but I think it is a healthy approach to accept there are downsides in certain cases (that applies for everything probably).