Porn addiction isn’t a thing. It’s made-up bullshit by people that buy into Judeo-Christian morality regarding sexual “purity”. There are reasons that it didn’t make it into DSM-V, and won’t make it into DSM-VI either. The porn and masturbation isn’t the problem, it’s how people feel about it, and how they reconcile it with their own beliefs in morality, which is not even remotely the same as being addicted to opiates or nicotine.
You can only be physically addicted to certain substances but you can be mentally addicted to anything.
You mean, you haven’t met someone with a mental addiction yet.
But — you are technically correct, indeed.
In ICD 10 the disorders that are commonly regarded as mental addictions are classified not as addiction, but as eating disorders, habit and impulse disorders and disorders of sexual preference. Don’t know whether I missed any.
BTW, Substance-related addiction is classified as mental and behaviour disorder due to psychoactive use. So, technically, “addiction” does not exist at all.