People continue to ask the same questions about porn that they have for decades: Is porn good for us or bad for us? Is it immoral or is it empowering? Damaging or liberating? Asking these questions inevitably leads to an intense clashing of opinions and little else.

One question that is not being asked: What is porn doing to us and are we OK with that? There is a growing body of research that says watching porn may lead to some not so desirable individual and social outcomes both in the short- and long-term.

Some people can watch porn occasionally and not suffer significant side effects; however, plenty of people out there, including teens and pre-teens with highly plastic brains, find they are compulsively using high-speed Internet porn with their tastes becoming out of sync with their real-life .

Just visit the sites YourBrainOnPorn and Reddit’s No Fap (no masturbating to online porn) forum to see stories from thousands of young people struggling to overcome what they feel is an escalating compulsion.

In the first-ever brain study on Internet porn users, which was conducted at the Max Planck Institute for Human Development in Berlin, researchers found that the hours and years of porn use were correlated with decreased grey matter in regions of the brain associated with reward sensitivity, as well as reduced responsiveness to erotic still photos.[1]

Less grey matter means less and fewer dopamine receptors. The lead researcher, Simone Kühn, hypothesized that “regular consumption of more or less wears out your reward system.”[2]

This is one of the reasons why Playboy, the magazine that introduced most of us to the naked female form, will no longer feature nude playmates after early 2016. As Pamela Anderson, who is featured on the cover of the final nude issue, said, “It’s hard to compete with the Internet.”[3]

A separate German study showed users’ problems correlated most closely with the numbers of tabs open and degree of arousal.[4] This helps explain why some users become dependent on new, surprising, or more extreme, porn. They need more and more stimulation to become aroused, get an erection and attain a .

A recent study led by researchers at the University of Cambridge found that men who demonstrate compulsive sexual behavior require more and novel sexual images than their peers because they habituate to what they are seeing faster than their peers do.[5]

Another recent study from the University of Cambridge found that those who have compulsive sexual behavior exhibit a behavioral that is comparable to drug addiction in the limbic brain circuitry after watching porn. There is between their sexual desires and their response to porn—users may mistakenly believe that the porn that makes them the most aroused is representative of their true sexuality.[6]

It may be no coincidence then that porn users report altered sexual tastes,[7] less satisfaction in their relationships[8] and real-life and problems.[9]

A lot of young men especially talk about how porn has given them a “twisted” or unrealistic view of what sex and intimacy are supposed to be, and how they then find it difficult to get interested in and aroused by a real-life partner.

Indeed, for many of them a real-life sexual encounter can be a foreign and -provoking experience. This is because communication skills are required, their entire body needs to be engaged and they must interact with another three-dimensional flesh-and-blood person who has their own sexual and romantic needs.

The book Sex at Dawn offers a relevant metaphor:

There's an old story about a trial of a man charged with biting off another man's finger in a fight. An eyewitness took the stand. The defense attorney asked, "Did you actually see my client bite off the finger?" The eyewitness said, "Well, no, I didn't." "Aha!" said the attorney with a smug smile. "How then can you claim he bit off the man's finger?" "Well," replied the witness, "I saw him spit it out."[10]

Think about this in the context of young people watching online porn. Though the effects that online porn has on the brain and behavior have not yet been fully determined, never before in human history have young men experienced the phenomenon known as porn-induced (PIED).

In the first comprehensive study of male sexual behavior in the U.S., which was conducted by Alfred Kinsey in 1948 and published in the subsequent book Sexual Behavior in the Human Male, just 1 percent of men under 30 years old and 3 percent of men between 30 and 45 years old, reported erectile dysfunction.[11] Yet, in a recent study, more than a third of young military servicemen reported experiencing erectile dysfunction.[12] Other recent studies had similar findings among non-military youth around the world, with rates showing a marked increase after high-speed Internet porn became widespread.[13] [14] [15]

For our upcoming book, Man Interrupted, we interviewed a number of young men regarding their concerns about porn and how there is a lack of guidance for the overuse of porn. A common sentiment among them was: “I'd like to know that more psychologists acknowledged at all degrees of severity. If that were the case I'd be less pessimistic about telling them about my problems.”

They also talk about how other areas of their life are affected, such as and emotional well-being, by watching excessive amounts of porn because they notice massive positive shifts in their personal lives and outlooks once they stop masturbating to it.

These young men often recount how their drastically improved–including an increase in , eye contact, and comfort interacting with women. They also report more energy to get through their daily lives, concentration becoming easier, being alleviated, and stronger erections and sexual responsiveness after voluntarily engaging in a “no fap” challenge.

Regardless of how one might feel about porn’s value, more and more studies suggest porn users suffer detrimental effects. Ultimately, more research needs to be conducted. However, if in the meantime we continue to deny that porn can be a problem for some people, we are effectively denying these people, many of them underage, help and guidance.

This post was co-written with Nikita Coulombe. Also see the book, Man Interrupted, and TED talk on the "Demise of Guys."