Yes.
I have been educating myself about this for more than a year now (for many reasons, including an academic research paper) and to reply to your question: Yes, watching porn changes the brain a lot more than you would think.
Most of the literature opposing “pornography addiction” focuses on explaining that research in the topic is either insufficient or incomplete and many also try to play on the definition of “porn” and “addiction”.
Regardless, I’m not here to say whether porn is intrinsically bad or good, but rather to let you know that it does in fact change your brain (psychologically, neurologically and physically speaking). It also affects your overall health, perspective on life, and real-life relationships regardless of whether it can be termed an addition or not.
Just focusing on the effects on the brain:
1- It induces a reward seeking behavior by releasing high levels of Dopamine
Just like the use of drugs such as cocaine, methamphetamines, and opioids highjack our brain’s reward system by exaggerating the release of dopamine to unnatural levels, porn does too.
2- It can result in addiction
These high levels of Dopamine releases can desensitize your brain, ultimately leading to addiction.
3- Watching port can result in what is now termed as Porn-Induced Erectile Dysfunction
This does not mean that males have physical problems, but rather that at some point, some men need a lot more arousal because mentally, their brain has been changed/desensitized.
Some men have also said that they need to think of porn while having sex in order to keep up with their partner.
The following article explains this more in detail with references to scientific papers: https://www.medicalnewstoday.com/articles/317117.php
4- Structural differences in the brain: High volume porn viewers showed less gray matter in a person’s right cuadate.
Of course, the research doesn’t specify a causal relationship between both but the physical difference exists.
Ultimately, it all comes down to the fact that watching porn can result in an addiction. And like any addiciton, this is not good.
Further Reading:
1- https://www.telegraph.co.uk/men/thinking-man/scary-effects-pornography-21st-centurys-accute-addiction-rewiring/
2- https://www.greymattersjournal.com/the-brain-on-porn/
3- https://www.inverse.com/article/31799-brain-on-porn-erotica-neuroscience
4- https://www.yourbrainonporn.com/research/