In the world of clinical trials, research sites occasionally have a strange feeling of déjà vu—”It’s you again?” That familiar face showing up for another screening visit may not just be coincidence. In fact, it’s often a warning sign of a growing issue in clinical research: professional patients and duplicate subjects in clinical research.
These individuals aren’t just re-enrolling at the same site. Many travel between sites—even across states or countries—enrolling in multiple studies at the same time or in quick succession. Some even attempt to join the same trial more than once at different sites. But the problem doesn’t stop there. A more insidious version of this behavior involves serial enrollment across different sponsors, different therapeutic areas, and different indications. These subjects may be participating in a CNS trial one week and a vaccine trial the next.
This is why a cross-sponsor, cross-therapeutic research subject database—like the one provided by Verified Clinical Trials (VCT)—is not just helpful, it’s critical.
The Problem with Professional Patients
These so-called “professional patients” are not driven by scientific contribution, but by financial gain, free medication, or access to care. Their behavior compromises the safety of clinical trial participants and threatens the integrity of research data.
Here are just a few common patterns:
- A subject screens for the same study at multiple sites to increase their odds of enrollment.
- A subject completes a study with one sponsor and immediately joins another without disclosing recent participation or washout violations.
- A subject misrepresents medical history or medications to qualify for trials across unrelated therapeutic areas.
This results in:
- Protocol violations (e.g., failed washouts, overlapping study enrollment)
- Adverse events that may go unreported or misattributed
- Corrupted data due to unblinded or motivated behavior
- Increased costs due to unnecessary screening, site burden, and early terminations
The Only Real Solution: Cross-Sponsor, Cross-Therapeutic Protection
Sponsor- or CRO-specific solutions simply don’t go far enough. Professional patients don’t stay loyal to one sponsor. That’s why only a centralized, real-time, cross-sponsor, cross-therapeutic registry can stop this problem before it begins—at the time of screening, not after the damage is done.
Verified Clinical Trials is the largest and most comprehensive global registry of its kind, with coverage across thousands of studies, sites, and therapeutic areas. We prevent over 100,000 protocol violations and duplicate enrollments annually and support nearly 40 countries worldwide.
Why This Matters to You
Whether you’re running a dermatology study, a CNS trial, or an obesity protocol involving GLP-1s, your study is at risk. Professional patients don’t discriminate—they’ll enroll wherever there’s an incentive. Protect your data, your budget, and—most importantly—your patients by making Verified Clinical Trials a part of your research infrastructure.
