Catherine has been unable to obtain crack for several

weeks because she has had no money, and so has not taken any for the past

month. She went through withdrawal symptoms when she was unable to take her

usual dose. She craves the drug all the time and is constantly searching for

ways to get some. Her efforts to obtain crack have seriously interfered with

her ability to work and take care of her children. This has been going on for

couple years. Which of the following