It's a spiritual disease. You are correct in speculating that one addiction can be switched with another - cannabis, pornography/hookers/affairs, heavier drugs. The bad part is, unless one surrenders, if a person is a bona fide addict, their full blown illness will drive them to depression, unmanageability, prison... possibly suicide.
The good news is, if one surrenders, he or she can suspend the progress of the disease.