Addiction can be a multifaceted problem. It includes compulsive behaviour, feelings of powerlessness, loss of control, and often physical dependence too.
There can be underlying unprocessed trauma(s) that fuels an addiction, and results in the individual turning to self medication and the abuse of illicit drugs and alcohol as a coping mechanism.
Addictions can also be expressed as an activity towards people, objects or anything that the person feels they are having no control over, and are oblivious to the damage in their life that the addiction causes to themselves and others.
CBT for addiction focusses on the thinking and behaviour patterns by learning to recognise the thoughts and feelings that trigger addictive behaviour. CBT can help to discover the reasons behind the addictive behaviour, helping to set goals while feelings, thoughts and behaviours are monitored and managed.
If physical dependence of drugs or alcohol is present, the CBT therapists would work with other professionals to make sure that physical dependency is managed appropriately and in a safe way prior to each session.
Addictive behaviour can also be learned. Which would instead make it a rather bad habit, however whether it is a bad habit or not, if one is not able to stop doing it by just deciding, then it is most likely addiction and the deeper meaning behind could be explored.