This study main objective is investigating impulsivity on cocaine or crack addicts. The investigators main hypothesis is that different measures (such as scales or behavioral tasks, for example) of impulsivity may produce distinct outcomes, and they might also differ among cocaine (sniffed) and crack users. Thus, it would be of great value to compare such measures once these data are often interpreted as the same phenomenon.

Drug dependence is characterized by a sum of cognitive, behavioral and physiological symptoms. Among these symptoms are the lack of control over ones own behavior and substance use even in face of significant issues related to it. Impulsivity (expressed as impulsive choice or fail on behavioral inhibition) is important in crucial phases of drug dependence development. Both behavioral and neurobiological studies have confirmed the association between impulsivity and addictive behaviors. Thus a high impulsivity level might have influence on patients' treatment. Even though, several questions on this matter remain unclear for humans, such as the differences on impulsivity between users of different forms of cocaine (either sniffed or smoked). This kind of difference could establish distinct ways of treatment and then enable developing better treatments for drug users. For this study it will be recruited 60 non-treated dependent patients, among them 30 cocaine users and 30 crack users. These individuals will be selected based on DSM-IV dependence criteria. The instruments used will be scales to measure compulsion and consumption of cocaine/crack, a pharmacological screening for psychotropic drugs and a cognitive evaluation. As impulsivity measures are Barratt Impulsivity Scale (BIS 11), a reward discounting questionnaire and a computer-based behavioral test on "ProgRef v3" software. For data analysis the impulsivity measures will be compared with the behavioral and cognitive instruments through the Pearson's correlation matrix. An ANOVA will be also performed to verify any differences between cocaine and crack dependents on the impulsivity and compulsion tests. When it is appropriate subsequent Newman-Keuls post-hoc test will be performed. Significance level adopted is 0.05.

Inclusion Criteria:

• Male
• 18-50 years old
• Cocaine/ Crack dependence criteria according to DSM-IV
• Have at least high school education level

Exclusion Criteria:

• Present dependence criteria for other drugs, except for Nicotine/tabacco
• Have any other psychiatric conditions