5. Any clinically significant laboratory finding as determined during the screening procedures that could impact brain function or study procedures as evidenced from clinical laboratory results. Since half of the participants in the study will have a diagnosis of cocaine use disorder (CUD), we expect some clinically significant findings that would reflect their recent cocaine use. As an example, a participant might have a mildly elevated Creatinine Kinase as a result of recent cocaine use. The test would reflect an acute rhabdomyolysis due to recent cocaine use, and it would be clinically significant. Nevertheless, if it is a mild episode as expected with cocaine use, it would not affect brain functioning or increase the risk of the procedures for the participants in the study. Therefore, not all abnormal laboratory findings that have clinical significance will be excluded. If a finding reflects altered brain function (e.g., arrhythmias or renal failure) it will be exclusionary for the study.