It doesn't discuss porn addiction directly, but much of what it is saying I think is applicable.
Researchers began to use the term pathological learning for the process that occurs when addictive substances or behaviors augment release of the neurotransmitter dopamine, turning what evolved as a beneficial process into a pathological one. Dopamine does its work of reward and conditioning in pathways originating in or near the limbic midbrain, a key region for regulating mood, pleasure and pain.
The pleasurable effect depends, in part, on the intensity of the signal that dopamine produces after release into the synapses. In neurons as in life, first impressions matter. People keep on doing what their brains tell them is highly rewarding, often past the point where it is still pleasurable or beneficial. Addicts want something after they have ceased liking it, even if they realize its harmful effects. “I hate this shit,” a Swedish heroin addict told his doctor, “and it doesn’t give me much of a high. It is just that somehow, it seems I can’t be without it.”
Researchers identified common risk factors. Genetic variations and life circumstances—stress, social defeat, neglect or abuse during critical periods of brain development—make some people more susceptible to addiction than others. They feel uncomfortable or depressed until they discover that alcohol, drugs, sugar, gambling, computer games or some other thrilling behavior temporarily banishes their blues. Frequent resort to these substances and behaviors further damages their neural control systems and, often, other parts of their brains. What the Victorians called vice really is a vicious circle. Self-destructive habits are constitutionally linked, downwardly spiraling, and socially expansive. “Addiction is a memory, it’s a reflex,” summed up the American psychiatrist Charles P. O’Brien. “It’s training your brain in something which is harmful to yourself.”
Or having your brain trained. The deeper truth is that we live in a world nominally dedicated to progress, health, and longevity but in fact geared toward getting us to consume in ways that are unprogressive, unhealthful and often deadly.
In brief, civilized inventiveness weaponized pleasurable products and pastimes. The more rapid and intense the brain reward they imparted, the likelier they were to foster pathological learning and craving, particularly among socially and genetically vulnerable consumers. Meanwhile, globalization, industrialization and urbanization made these seductive commodities and services more accessible and affordable, often in anonymous environments conducive to anomie and saturated with advertising. Accessibility, affordability, advertising, anonymity and anomie, the five cylinders of the engine of mass addiction, ultimately have found their most radical technological expression in the floating world of the internet.
"Weaponized pleasurable products"… "anonymous environments" … "saturated with advertising" … sound familiar?