We had a speaker at my last families anonymous meeting. Before he spoke a new mom talked and shared her story. When it was time for the speaker to talk he was so welled up with emotion he had a hard time speaking. He was a heroin addict who had been clean since 2005. He speaks regularly at numerous AA/NA meetings. The reason he said he was so overcome with emotion was because hearing the pain us moms were in reminded him of all the heartache he had caused his family. It's the one thing he hasn't been able to come to terms with after all these years... Knowing how much he hurt is family.
Hearing this made me realize that addicts do regret their actions, but when they're in the clutches of their addiction they are powerless to their addiction... Nothing else matters beyond getting their next fix. Are there some who are just antisocial and incapable of true feelings? Sure. But I think, hope, that is the exception.