Catherine has been unable to obtain crack for several weeks because she has had no money and so has not used the drug 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. Which of the following DSM-IV diagnoses would best fit Catherine's symptoms?

a. substance abuse
b. substance dependence
c. addiction
d. Catherine does not qualify for a DSM-IV diagnosis since she has not used the drug for the past month.