Performance-Validity Testing in Cannabis Research Was Not a THC Detector
A performance-validity measure addresses engagement with testing rather than whether THC was present or caused a cognitive change. The medical-cannabis review described it as an additional part of one assessment battery.
The review explained the intended role
The Brief Neurocognitive Battery study included performance-validity testing to help evaluate effort or engagement. Such measures are intended to assist interpretation of the test record. They are not chemical assays and do not identify a cannabis dose or exposure time.
An interpretable performance can still be affected
Evidence that someone engaged adequately does not establish that all cognitive capacities were normal. A person can participate credibly while experiencing genuine difficulty. Conversely, a problematic validity result requires contextual evaluation rather than automatic attribution to THC or deliberate misconduct.
Keep the evidentiary steps separate
The review’s description does not establish a sensitivity or specificity for detecting cannabis impairment with these validity measures. Nor does a valid performance demonstrate safe driving. The appropriate sequence is to assess whether the results can be interpreted, then examine what the cognitive outcomes show and how the experimental comparison supports attribution. Collapsing these steps turns a tool for evaluating test interpretability into a diagnostic claim the supplied evidence did not validate.
Related analysis: the review’s broader findings and limitations.
Research cited
This analysis draws on the supplied review: Eadie and colleagues (2021). Duration of Neurocognitive Impairment With Medical Cannabis Use: A Scoping Review. Frontiers in Psychiatry.
