As reported in Psychology Today:
it seems that people think about physical addiction and psychological addiction as somehow separate processes. I think this distinction makes no sense. Even if people really meant what they were saying, the brain is undoubtedly part of the body, and therefore, psychological addictions are also physical.
The “Physical Addiction” Vs. “Psychological Addiction” truth
What people are really referring to when they make this comparison is the distinction between physical withdrawal symptoms that are part of physiological dependence and the addictive process in the brain. There’s no doubt that some substances, like alcohol, opiates, and the likes, leave long term users with horrible withdrawal symptoms that are terrible to watch, and even worse to go through. In fact, early addiction theories asserted that it was this horrible withdrawal syndrome that made people go back to drugs. This was called the Tolerance-withdrawal addiction theory.
Read the rest of the article here: http://www.psychologytoday.com/blog/all-about-addiction/201007/physical-addiction-or-psychological-addiction-is-there-real-differen