In addition, those who take drugs also risk addiction, a type of disease of varying severity depending on the type of drug used.
No as an addiction is considered a disease under the current rule set.
Just to add to Firewarrior's post.
As addictions are diseases, they can be cured as such, through the use of spells like remove disease or by succeeding at Fortitude saves over time. Unlike with other diseases, an addicted character can only make a Fortitude save to overcome his addiction after a day of not taking the drug he is addicted to. The DC of this Fortitude save is equal to the highest addiction DC his drug use has reached (not necessarily the DC that addicted him if he has continued to make use of the drug while addicted). This DC decreases by –2 for everyday the character does not make use of the drug, to a minimum of the drug’s base addiction DC.