All kinds of psychiatric conditions as well as exposure to environmental stressors are seen to correlate with areas of increased or decreased volume and activity in the brain. This is different from saying “his dopamine receptors are damaged”.
https://www.hazeldenbettyford.org/education/bcr/addiction-research/drug-abuse-brain-ru-915
Ultimately, people who have drug and alcohol and other addictions, like pornography, are looking for the reward that comes from the release of dopamine.