1. The number of non users had...
- Not changed
1 of 20
Other questions in this quiz
2. Different questions were used each time an interview took place
3. What was their mean age?
4. 106 participants had...
- stopped using cocaine by the end of the study
- increased their heroin intake by the end of the study
5. 147 participants had...
- reduced their cocaine use
- doubled their cocaine use