Delay Discounting Task: A 5-trial adjusted delay discounting task (28 (link)) was used to measure delay discounting. A subject’s temporal discounting rate is calculated as a “k” value (29 (link)). A higher temporal discounting rate (i.e., a higher “k” value) is associated with greater impulsivity (29 (link)). The logarithm of the k value [log10(k)] is calculated to obtain a more normal distribution across subjects (29 (link)).
Cocaine and Cannabis Use: The number of subjects with UDS positive for cocaine and cannabis are reported for descriptive purposes.
Tobacco use was assessed by the Fagerström Test of Nicotine Dependence (38 (link)). Subjects were classified as current tobacco users if they responded that they had used tobacco products within the past year, or non-current tobacco users if they responded that they had not used tobacco products within the past year.
Behavioral data were analyzed using the JMP statistical software package (JMP, Version 14. SAS Institute Inc., Cary, NC, 1989-2019). A two-sample T-test was performed to test for statistical significance between groups with respect to age, education, tobacco use, head motion (mFD score), and delay discounting task scores.
Cocaine and Cannabis Use: The number of subjects with UDS positive for cocaine and cannabis are reported for descriptive purposes.
Tobacco use was assessed by the Fagerström Test of Nicotine Dependence (38 (link)). Subjects were classified as current tobacco users if they responded that they had used tobacco products within the past year, or non-current tobacco users if they responded that they had not used tobacco products within the past year.
Behavioral data were analyzed using the JMP statistical software package (JMP, Version 14. SAS Institute Inc., Cary, NC, 1989-2019). A two-sample T-test was performed to test for statistical significance between groups with respect to age, education, tobacco use, head motion (mFD score), and delay discounting task scores.
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