We have been talking about the concepts of denial, dishonesty, and Manipulation in our family class for years. In her recent book "Addict in the Family", published by Hazelden, Beverly Conyers spells it out very clearly. Addiction is very predictable and all addicted people will deny they have a problem, lie, cheat and steal and manipulate situations and people to get what they want, and that is their drug of choice.
Remember, addiction is a brain disease and the brain is altered in important ways at the cellular level because of this disease process. You can not see addiction, but you can see the result of addiction in the dishonest and manipulative behavior that addicts display regularly. This behavior is very understandable when you are clear that what an addicted person believes and acts on is that their drug of choice is what makes life worth living.
Family members think in terms of relationships, children, career, and accomplishments as what make life worth living but that is not true for the addicted person.
Remember; "If their lips are moving they are lying." "Never trust an addicted person because you think you should or because you want them to be trustworthy so badly." "the only thing that counts with an addicted person is their behavior."