The other day, I overheard a guy say that Starbucks was “the greatest drug dealer in the United States.” Being a guilty party to that sort of “drug dealing,” I’ll recuse myself from discussing the merits of such a charge.

But what if I told you that the internet is the greatest drug dealer in the United States?”

A growing body of research supports such an assertion as it relates to a new “narcotic”: internet pornography. The National Survey on Drug Use and Health estimated that in 2008 there were 1.9 million cocaine users. According to the Central Intelligence Agency, there are an estimated 2 million heroin users in the United States, with some 600,000 to 800,000 considered hardcore addicts. Compare these numbers to the 40 million regular users of online pornography in America.

Neurological research has revealed that the effect of internet pornography on the human brain is just as potent—if not more so—than addictive chemical substances such as cocaine or heroin. In a statement before Congress, Dr. Jeffrey Satinover, a psychiatrist, psychoanalyst, physicist, and former Fellow in Psychiatry at Yale, cautioned:

With the advent of the computer, the delivery system for this addictive stimulus [internet pornography] has become nearly resistance-free. It is as though we have devised a form of heroin 100 times more powerful than before, usable in the privacy of one’s own home and injected directly to the brain through the eyes. It’s now available in unlimited supply via a self-replicating distribution network, glorified as art and protected by the Constitution.

Though pornography, in one form or another, has been around for most of human history, its content and the way people access and consume it have drastically changed in the past few decades with the advent of the internet and related technologies.

There are three main reasons internet pornography is radically different from earlier forms: its (1) affordability (K. Doran, Assistant Professor of Economics at Notre Dame University, estimates that 80% to 90% of porn users view free content online), (2) accessibility (24/7 access anywhere with an internet connection), and—most importantly—(3) anonymity. Those three factors combined with internet pornography’s experiential depiction of real people performing real sex acts while the viewer observes has created a potent narcotic—in the most literal sense.

Yet many would argue that pornography is merely “speech,” a form of sexual “expression” that should be protected as a constitutional right under the First Amendment.

The question of First Amendment rights is undeniably the ultimate hurdle to clear from a legal standpoint—and I take up that question in tomorrow’s Public Discourse essay. Today I begin my analysis from a scientific perspective, because recent neurological findings have exposed internet pornography to be something much, much more than mere “speech.”

Internet Pornography: The New Narcotic

While the term “drug addiction” typically has been reserved for chemical substances physically ingested (or inhaled or injected) into the body, internet pornography—taken in through the eyes—affects the brain chemically and physically in a manner similar to that of illegal chemical substances. William M. Struthers, Professor of Psychology at Wheaton College, explains in his book Wired for Intimacy: How Pornography Hijacks the Male Brain that pornography works “through the same neural circuit, has the same effects with respect to tolerance and withdrawal, and has every other hallmark of an addiction.”

This is because the same parts of the brain react to both illegal substances and sexual arousal. Dopamine, the chemical triggered by sexual arousal and orgasm, is also the chemical that triggers addiction pathways in the brain. As Donald L. Hilton Jr., MD, a practicing neurosurgeon and a clinical associate professor of neurosurgery at the University of Texas, observes:

Pornography is a visual pheromone, a powerful 100 billion dollar-per-year brain drug that is changing sexuality even more rapidly through the cyber-acceleration of the Internet. It is “inhibiting orientation” and “disrupting pre-mating communication between the sexes by permeating the atmosphere.”

Think of the brain as a forest where trails are worn down by hikers who walk along the same path over and over again, day after day. The exposure to pornographic images creates similar neural pathways that, over time, become more and more “well-paved” as they are repeatedly traveled with each exposure to pornography. Those neurological pathways eventually become the trail in the brain’s forest by which sexual interactions are routed. Thus, a pornography user has “unknowingly created a neurological circuit” that makes his or her default perspective toward sexual matters ruled by the norms and expectations of pornography.

These “brain trails” are able to be initiated and “paved” because of the plasticity of brain tissue. Norman Doidge, MD—a psychiatrist, psychoanalyst, and author of the New York Times and international bestseller, The Brain That Changes Itself—explores the impact of neuroplasticity on sexual attraction in an essay in The Social Costs of Pornography. Dr. Doidge notes that brain tissue involved with sexual preferences (i.e., what “turns us on”) is especially malleable. Thus, outside stimuli—like pornographic images—that link previously unrelated things (e.g., physical torture and sexual arousal) can cause previously unrelated neurons within the brain to learn to “fire” in tandem so that the next time around, physical torture actually does trigger sexual arousal in the brain. This in-tandem firing of neurons creates “links” or associations that result in powerful new brain pathways that remain even after the instigating outside stimuli are taken away.

In light of the new brain science, the relevant scientific community (the American Society of Addiction Medicine), which used to believe addiction was primarily a behavior, recently redefined “addiction” as primarily a brain disease revolving around the neurological rewards system. Internet pornography’s powerful force on the neurological reward system clearly places it within this new definition of “addiction.”

Some might argue that many substances and activities—such as TV, food, shopping, etc.—can cause addiction-forming chemicals in the brain, yet we certainly don’t want the government regulating how much TV we watch, how often we shop, or how much we eat. While there are plenty of people with addictions to TV, food, and shopping, Dr. Hilton argues that sexual images are “unique among natural rewards” because sexual rewards, unlike food or other natural rewards, cause “persistent change in synaptic plasticity.” In other words, internet pornography does more than just spike the level of dopamine in the brain for a pleasure sensation. It literally changes the physical matter within the brain so that new neurological pathways require pornographic material in order to trigger the desired reward sensation.

So how does internet pornography compare with illegal addictive chemical substances like cocaine or heroin? Cocaine is considered a stimulant that increases dopamine levels in the brain. Dopamine is the primary neurotransmitter that most addictive substances release, as it causes a “high” and a subsequent craving for a repetition of the high, rather than a subsequent feeling of satisfaction by way of endorphins. Heroin, on the other hand, is an opiate, which has a relaxing effect. Both drugs trigger chemical tolerance, which requires higher quantities of the drug to be used each time to achieve the same intensity of effect.

Pornography, by both arousing (the “high” effect via dopamine) and causing an orgasm (the “release” effect via opiates), is a type of polydrug that triggers both types of addictive brain chemicals in one punch, enhancing its addictive propensity as well as its power to instigate a pattern of increasing tolerance. Tolerance in pornography’s case requires not necessarily greater quantities of pornography but more novel pornographic content like more taboo sexual acts, child pornography, or sadomasochistic pornography.

Sexual arousal is the result of testosterone, dopamine, and norepinephrine surges, whereas the transcendence and euphoria experienced during orgasm are related to the release of endogenous opiates. While pornography activates the appetitive system by way of dopamine, an orgasm caused by pornography does not release endorphins, which are the chemicals that make us feel satisfied. By contrast, endorphins are released after an orgasm caused by having sex with a real human being. This lack of satisfaction, combined with the brain’s competitive plasticity, causes the brain to require more and more novel and extreme images to get the same chemical result as before.

While the addictive effects of internet pornography are similar to a combination of addictive chemical substances, internet pornography’s effects go beyond those of chemical substances.

For instance, “mirror neurons” in the brain enable us to learn by watching a behavior and copying it. Professor Struthers writes that, because of mirror neurons, “Viewing a pornographic [video] creates a neurological experience whereby a person vicariously participates in what he is watching.” This uniquely interactive addiction is enabled by the combination of stimuli upon both the brain and the body; in Struthers’ words, porn use “involves the visual system (looking at porn), the motor system (masturbating), the sensory system (genital stimulation), and neurological effects of arousal and orgasm (sexual euphoria from chemical opiates like addictive dopamine in the nucleus accumbens and reduced fear in the amygdala).”

Another aspect of pornography addiction that surpasses the addictive and harmful characteristics of chemical substance abuse is its permanence. While substances can be metabolized out of the body, pornographic images cannot be metabolized out of the brain because pornographic images are stored in the brain’s memory. While substance abusers may cause permanent harm to their bodies or brains from drug use, the substance itself does not remain in the body after it has metabolized out of the body. But with pornography, there is no timeframe of abstinence that can erase the pornographic “reels” of images in the brain that can continue to fuel the addictive cycle.

In sum, brain research confirms the critical fact that pornography is a drug delivery system that has a distinct and powerful effect upon the human brain and nervous system. More akin to cocaine than to books or public speeches, internet pornography is not the sort of “speech” the First Amendment was meant to protect from government censorship—as I will argue tomorrow. Those who read books or listen to ideas can use their conscious minds to reason through the assertions and information. But, as Dr. Doidge puts it, “Those who use [pornography] have no sense to the extent to which their brains are reshaped by it.” Indeed, they have no idea that pornography is developing “new maps in their brains.”