I want to add something to what is being discussed.
Being addicted is a choice. Addiction does not mean you cannot stop. It means one makes a choice not to stop. Addiction is medically studied but it is meaningless after you know and understand it is a lifestyle choice. The addicted person chooses to start, and chooses to continue, and if they want, chooses to quit. It makes no difference if it is a physical or psychological addiction or both. Granted, being addicted makes it tough to stop. But again, until one makes the decision to stop they are making the decision to continue with their addiction. Being addicted does not take away one's choice to stop being addicted nor does it take away the fact that one chooses to stay addicted.
No matter what the medical community lies and says to those of you who feel being addicted is a medical condition, it is still ones choice to start, continue and stop.
I've lived with addiction in my family my whole life. I've heard it stated some people have "an addiction-prone personality". Today it would be stated they have an obsessive-compulsive tendency. Just like gambling, there are "reward" centers in the brain that give one a good feeling when they win. They become addicted to that feeling and it becomes something the continue to seek, often to the detriment of other aspects of life, like paying bills or taking care of the family.
Alcohol and drugs become an easy "vacation" from the stresses of life. They don't fix the things that cause stress, but they mask the feelings of stress and make you feel happy for a short time.
Those are psychological addictions which may be tied to the physiological release of chemicals in the brain that create pleasure.
Add to that the physical addiction where you no longer feel good while taking the drug, but you feel bad if you don't.
You have to recognize that you're addicted and need to stop before a choice can be made. Then you need the willpower and maybe even medical assistance to get past the withdrawal and stop the addictive behavior.
Porn addiction is 100% psychological. The real question is, were you already a perv before you started craving porn, or did porn make you a perv? Just like video games don't make people serial killers, however serial killers may become obsessed with playing violent video games.