Addiction is a very popular theme for movies, making it relatively easy to find potential films about which to write. Simply enter into a search engine a binary search in the form "+movies +addiction".
Many films treat addiction in an unrealistic fashion and this assignment might give you an opportunity to think about the difference between how addiction is treated in the fictionalized setting of a film and how you would really treat an addict. One possibility might be to look at a film that glamorizes an addiction, and think about the underlying reality.
One interesting example might be the James Bond film series. In this film, we have a image of a man who is portrayed as a spectacular athlete as well as cool, intelligent, and unflappable, who is also portrayed as addicted to cigarettes and a very heavy drinker. As you go through your worksheet, you might examine whether, for example, someone who smoked and drank as much as Bond did could actually be in outstanding physical shape well into his fifties. Could any of his difficulties with forming normal human relationships be due to his drinking?