Yeoldetelephone

I don't know if it is agreed by medical and psychological experts that paedophilia is an orientation or not. Some people who have these desires, etc, were abused themselves as children and so there is trauma-based acting out. Other people do not respond this way. The whole situation is complex but the safety of children must be the first consideration.

The general work for this is the DSM5, which lays out pedophilic disorder on page 697-701, where it is classified as a paraphilia and a disorder, classified alongside other conditions that involve some sort of bypassing of normal consent processes (ie paraphilias involving objects or extreme violence, etc)

Not a psychologist, nor have I done research on CSAM, but have been in a team doing addiction research from another discipline.

An orgasm is a biological reward for behaviour, and if that behaviour involves representations of children then they are being rewarded for sexualising child-thing, which would probably reinforce the behaviour or increase its value when real children are encountered. There is little to no evidence supporting what's called the thermodynamic model of addiction (Ie. "pressure release") and long term behaviours tend expand rather than being relieved with repetition.

Additionally it would be very hard (albeit possible in some way I assume) to do any ethical research on this to get the answers you are after.