Sadly there doesn't seem to be any reputable studies in this field - probably because it's super controversial to begin with.

On one hand you have people saying - rightfully so - that such media should be restricted, because even though some argue (without proof) that it reduces harm, it also enables the core behaviour of sexualising children to be socially acceptable because "oh it's just a drawing".

(mind you it's important to distinguish a very similar argument from furries - furries are often claimed to be zoophiles, however an overwhelming majority of furries are against bestiality, and doesn't even sexualise their characters, which are usually anthropic - human shaped with animal physical characteristics - and sapient, therefore able to consent. A child, regardless if they're real or drawn, cannot consent).

On the other hand, some claim that it reduces harm by "disarming" paedos. Obviously those opposing then claim that no, it's actually harmful, because just jerking off to drawings won't be enough for most, and slippery slope fallacy ensue, they'll be gone from jerking to drawings, to kidnapping and raping children.

Again the problem is we don't have any data supporting either way. In my opinion, it could go either way, it heavily depends on the person, and without a thorough study, but that study wouldn't be ethical to conduct because of the potential of endangering children one way or another....

And of course the moment one tries to debate for "on the other hand", that person will be labelled a paedophile, rightfully so, as they're literally campaigning for the legalisation of children's sexualisation in their specific way... which, at the end of the day, is paedophilia.