IRP, NIDA, NIH, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA
* Sanofi Pharmaceuticals, Inc., 9 Great Valley Parkway, Malvern, Pennsylvania 19355

Out of 2991 telephone calls and walk-ins recruited for the marijuana study, 48% or 1425 candidates successfully completed the initial telephone drug and psychological history screening. These candidates were scheduled for further interviews. Thirty-nine percent or 559 participants received complete physical exams and extensive clinical laboratory and psychological evaluations. Seventeen percent or 99 participants were admitted to the pre-treatment phase of the study. Following further medical and psychological evaluations, 48% or 48 participants were randomized for experimental dosing. Most of the candidates initially screened were disqualified from participating in the study due to many factors, including: current active disease, clinical laboratory abnormalities, allergies, psychological or behavioral competence, current drug dependence or treatment, or an inability to comply with all study requirements due to legal or family social issues.

These factors represent a significant challenge to the recruitment of human research participants for drugs of abuse studies. The NIDA IRP has, over many years, developed procedures and personnel to address these issues to successfully recruit research participants, taking care to maintain the highest safeguards for the protection of human volunteers.