This post follows Your Brain On Porn, Part 1, where I discussed the four ways in which porn overstimulates the brain. In Part 2, I discuss how overstimulation leads to cravings, out of balance reward circuitry, and diminished capacity for satisfaction.
Every addiction occurs because the brain has adapted to being overstimulated—too much dopamine. As a result of porn use, three troublesome changes occur in the brain.
Overstimulation Leads to Cravings
Cravings occur when dopamine (the “I want it” neurotransmitter) is released. When more dopamine is released, a person experiences cravings.
Cravings usually lead to viewing more porn. Viewing more porn leads to more dopamine being released. More dopamine leads to viewing more porn.
You get the picture—it’s a potentially never-ending cycle.
Overstimulation Leads to Broken Reward Circuitry
In the center of the limbic system—the center of our urges and desires—there is a reward circuit flowing to the cerebral cortex—the rational part of the brain.
Ideally, this circuit works in harmony. When the limbic system urges you to have another piece of chocolate cake, the cerebral cortex reminds you that you can’t fit into your jeans, so you say, “No, thanks.”
In the case of a man whose brain is not yet addicted to porn, his limbic system may urge him to Google the words “naked women,” but his cerebral cortex reminds him that his wife or girlfriend may not think highly of such an act.
Porn, however, throws the reward circuit off balance. Rather than complete the circuit in harmony, porn trips the circuit breaker, and disharmony occurs between the two systems.
When the “go for it” system is overloaded with excess dopamine, the “think about it” system responds by saying, System overload! and shuts down. Suddenly, rationale thought is usurped by limbic impulse.
Overstimulation Leads to Numbed Pleasure Response
Across the synapse—the micro space between neurons—reward cells talk to one another through dopamine signaling. Dopamine, remember, is the message, and the receptors on the receiving nerve cells are the ears.
When dopamine is released in large amounts or for long periods, two things happen simultaneously.
First, the receiving nerve cells get overstimulated and start removing receptors. It’s like when someone keeps shouting at you; you cover your ears. But the sending cells scream even louder (more dopamine) until they are hoarse, and can now only whisper (amount of dopamine sent is below normal).
With the receiving cells half-deaf (fewer receptors) and the sending cells whispering (less dopamine released), you are left with two options—feeling awful, or finding porn, the one thing that now releases dopamine more than anything else.
Low dopamine signaling leads to a numbed pleasure response and is known as desensitization.
What this leads to is increased craving, alongside decreased ability to experience satisfaction. It is precisely why men feel so helpless, so powerless, when they try to overcome their sexual addiction.
Always hungry, but never full.
C.S. Lewis Understood Addiction
In 1942 C. S. Lewis wrote The Screwtape Letters, a story about a senior demon named Screwtape who instructs a junior demon named Wormwood, in the wiles of evil:
“An ever-increasing craving for an ever-diminishing pleasure is the formula,” Screwtape advises. “It is more certain; and it’s better style. To get the man’s soul and give him nothing in return—that is what really gladdens our Father’s [Satan’s] heart.”
Even in Lewis’s vivid imagination, I’m almost certain he never envisioned MRI machines and PET scanners, which today support his theological idea.
The human brain is truly “fearfully and wonderfully made.” Stay tuned for Your Brain On Porn, Part 3!
Question: How does understanding the brain on porn change the way you perceive the struggle?
Excerpted from Surfing for God: Discovering the Divine Desire Beneath Sexual Struggle by Michael Cusick. Copyright ©2012. Used by permission of Thomas Nelson, Inc. www.thomasnelsoncorporate.com.