This section contains a few selected research papers on behavioral addictions. A common argument against the existence of porn addiction is that it can't be an real addiction because it's not a drug.
All addictions involve hijacking of the same neurocircuitry, and alterations of many of the same mechanisms and neurochemicals. A basic physiological principle is that drugs do not create anything new or different - they simply increase or decrease normal brain functions. In essence, we already possess the machinery for addiction (mammalian bonding/love circuitry), and for binging (yummy food, mating season).
Science has demonstrated the same addictive changes occurring in Internet addiction, pathological gambling and food addiction, as occur in drug addiction (please see other sections for specific studies). Only a single factor makes porn addiction unique: very little research has been done on it to date. Even so, the latest scientific advances how that criticisms of the sexual-behavior addiction model are unfounded and outdated. See this 2015 paper by two doctors: Sex Addiction as a Disease: Evidence for Assessment, Diagnosis, and Response to Critics. Or view a chart from this paper, which takes on specific criticisms and offers citations that counter them.
For a neurosurgeon's look at the science behind porn addiction read his talk delivered at SASH (The Society for the Advancement of Sexual Health) entitled, "Changing the Stamp of Nature: Pornography Addiction , Neuroplasticity, and the ASAM and DSM Perspectives."