Informed Consent in Vulnerable Populations: The Case of Detained Persons with Attention Deficit Hyperactivity Disorder.

Informed consent (IC) is a critical component in research involving human participants, yet participants' understanding of consent information remains underexplored, particularly in vulnerable populations. This study aimed to assess whether attention deficit hyperactivity disorder (ADHD) was associated with understanding and willingness to sign the IC among detained individuals. This secondary analysis used data from a randomised trial conducted in a Swiss prison (n = 183). Statistical analyses included regression models. There was no significant difference in understanding of the IC between the groups with and without positive screening for ADHD (mean score = 5.2 vs. 4.9 respectively, p = .468). Acceptance of signing the IC was comparable between groups (83.3% ADHD vs. 84.9% non-ADHD, p = .814). Our findings suggest that ADHD did not significantly impair the understanding of the IC or the decision to participate in research among detained individuals. However, the level of understanding was overall low, highlighting the need for tailored approaches to improve understanding in vulnerable populations.